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tcj_30 1987-06

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2. the first available non floppy drive selection as our MDISK drive We must then modify the DPH for drive F If you re using a different drive letter for MDISK modify the DPH for that drive instead DPHMD is the MDISK Disk Parameter Header and contains infor mation that helps define the MDISK disk drive The first byte is the address of the logical to physical translation vec tor MDISK doesn t use translation so we set that byte to zero The next three bytes are scratchpad areas DIRBUF is the ad dress of a 128 byte scratchpad area for directory operations and is shared by all the drives It is not modified MDPARM is the address of the MDISK disk parameter block which defines the characteristics of the MDISK RAM disk The Computer Journal Issue 30 Dama un Listing 2 Drive F is shown DPBASE the BIOS hard disk information is skipped in this listing IF NOT HARD D1 SK 22 22 3 nsert modified code as shown below insert DPHMD as a replacement for the DPH for whichever 3 drive tetter you have selected for MDISK here OPHMO DEFW 2 23 2 End of modified inserted code DEFW etc up through drive P DEFW 0 0 0 0 DIRBUF SPARM CSVP ALYP ENDIF j 7533522223 insert modified code as shown below s s s ssss sss 5 2 5 MDPARM DEFW 128 SPT Sectors track DEFB 4 BSH Block shift OEFB 15 BLM Block mask DEFB 4 CHIPS 2 EXM Extent mask DEFW 128 CHIPS 41
3. Parameter lists are checked and resemble those of Modula2 except commas and semicolons are not used Control structures like Modula2 except each has a ditferent ending word IF ENDIF WHILE WEND FOR NEXT etc No braces or BEGIN END needed for muitiple statements in IF etc Procedure RETURN like that of Modula2 Procedures nest tike those of Modula2 Local varlables can be static or auto Varlabie Initlailzation can be done with a simple predicate in the definition or with an arbitrary number of seperate statements mix of BASIC C Modula2 amp assembly To visualize the interactive aspect of the system imagine starting with Turbo Pascal and expanding the command shell to include the operating system Then add assembly statements to the language Then add commands similar to those of a machine language debugger move display disassemble etc Then add the ability to execute any Pascal statements or assembly statemen ts from the keyboard Then add the keywords STOP and CONT to the language The compiled code for STOP is a call to the command loop runtime regs are saved When in the stopped condition you can look at variables or registers change variables or registers call procedures single step the machine instructions of the program etc When you type CONT the program then continues If you know the address to stop at you can set a breakpoint from the keyboard instead of recompiling to insert the STOP You ca
4. DIRBUF DEFS 128 DIRECTORY ACCESS BUFFER 222 222 insert modified code as shown below 2 22 s22s222 2x22222 2 MBUF gt DEFS 128 Memory buffer for MDISK CSVMD DEFS MD CKS ALYMD DEFS MDS ALY 2222222 End of modified iInserted code s xzzzzzzzzzazzzzzzzzuzxz22zz gt Floppy drive directory check vector storage DEFS 128 DIRECTORY ACCESS BUFFER F and A The ZCPR3 utility PATH 0 current a user oi t r can be used to change your file search Ha ee is Beaty path to accommodate your new system FO Your physical drive A user 0 The path should begin with the current FI5 Your physical drive A user 15 drive and user then move to drive A your logical MDISK drive and if you keep all your utility files in the disk in physical drive A which is now logical drive F then that is where the path should end up Your new path assignment might look like the following which assumes that you only use MDISK user 0 Organize the new path to suit your own system and work habits MDISK LBR contains MDISK COM a utility that will take care of all this for you when it is included in your STARTUP alias 35 Setting Up MDISK Using ALIAS Files disk you will need to copy the utility and working files you will be using from your utility disk to MDISK You can use VALIAS and ACOPY to easily create powerful SETUPxxx utilitie
5. eered gt y foreground The data In the 128 byte hoiding butter aust ce copied Into the write buffer before i s sent to the floppy disk Set by background and cleered by foreground 11 The problem was that the background routine returned to the caller as soon as the disk was inserted It should have waited for the density check Under these conditions the caller thought a single density disk was in the drive when it really was double den sity or vice versa The solution required restructuring of the door check routine When first tested the new double density routines I found some programs losing data from the end of their write files This was due to these programs not closing their output files Rather they simply wrote the last record and then performed a warm boot The final write buffer was never being flushed to the disk This was solved by having the warm boot code check for a deferred write and flushing the buffer if needed This cleared up the problem Related to the no disk problem above is a fundamental problem that does not seem to have a solution The scenario is this Suppose a drive has a single density disk in it and the BDOS knows about this disk If the door is opened and the disk is traded for a double density disk the BIOS knows this and performs all the required actions to read the disk But somewhere inside the BDOS is a data field that cannot be reached The next time the BDOS tries to read the disk i
6. OSM Disk size DEFW MDIRSIZ 1 ORM Dir max DEFB 110000008 ALO Dir bit map for 128 entries DEFB 000000008 ALI Dir bit map DEFW 0 CKS Check size DEFW 1 3 OFF Track offset ist track is system 2222 End of modified inserted code ENE E E SPARM Ampro single sided 48tpi and is discussed in more detail below CSVMD is the address for the scratchpad area used to check for changed disks MDSCKS which we have set to zero earlier is the size of this area ALVMD is the address of the scratchpad area for BDOS disk storage allocation infor mation MDSALYV also set earlier is the size of this area MDPARM contains 15 data bytes of disk information that describe the charac teristics of the disk organization The first byte SPT is the number of 128 byte records per track We use 128 which gives us 16k tracks The next two bytes are the block shift factor BSH and the block mask BLM Because our block size is 2k it turns out that our BSH should be 4 and our BLM should be 15 The next two bytes are the extent mask EXM and the disk size 1 DSM Given a block size of 2k both of these values depend on the number of chip sets that we have installed EXM is determined by the block size and 0 0 0 0 DIRBUF MOPARM CSVMD AL VMD 0 0 0 0 01RBUF SPARM CSVG ALVG the total number of blocks If we install one or two chip sets EXM will be 1 Either 3 or 4 chip sets will require an EXM of 0
7. Redirectable 1 0 Package 1OPS EQU 0 3 size in 128 byte blocks New Code lop EQU OECOOH Redirectable 1 0 Package lOPS EQU 12 3 size ia 128 byte blocks Next we need to change the BIOS jump table to re direct certain jumps to the IOP The jump table is at the start of the BIOS just after the ORG BIOS statement Old Code JMP BOOT Cold start WBOOTE JMP WeOOT Warm start JMP CONST Console status JMP CONIN Console character in JMP CONNOUT Console character out JMP LIST List character out JMP PUNCH Punch character out JMP READER Reader character In JMP HOME Seek to home pos tion JMP SELOSK Select disk JMP SETTRK Set track number JMP SETSEC Set sector number JMP SE TOMA 3 Set DMA address JMP READ Read disk JMP WRITE Write disk JMP LISTST Return tist status JMP SECTRAN Sector translate New Code JMP BOOT Cold start WBOOTE JMP weooT Warm start Je 10P 12 Console status IP 10P 15 3 Console character in IP 10P 18 Console character out IP 10P 21 3 List character out P 1OP 24 3 Punch character out IP 10P 27 Reader character in JMP HOME Seek to home position JMP SELDSK Select disk JMP SETTRK 3 Set track number JP SETSEC Set sector number JMP SETOMA 3 Set OMA address JMP READ Read disk JMP WRITE Wite disk aP LoP 30 Return list status g 3 Sector translate 13 Now find the label HDCODE which is just before the Cold Boot Entry HOCODE EQU End of har
8. The Editors of Computer Language Al Expert Unix Review and Database Programming amp Design recently announ ced ccmpletion of the agenda for Sof tware Development 88 a three day con ference which will take place February 17 19 1988 in San Francisco at the Ramada Renaissance Hotel off Union Square The conference is being organized to provide practical information to professional software developers Six to eight hundred developers are expected to participate As many as sixty speakers will present ninety lectures and workshops over the three days Among those confirmed as speakers are Bill Gates Dick Gabriel Ester Dyson P J Plauger Gary Kildall Jack Purdum Alan Kay Charles Moore John Warnock and Philippe Kahn Topics ranging from Artificial Intelligence and Design Methodologies to Languages Data Base Design and Graphics will be covered In addition to lectures and technical workshops there will be an exhibit by in dustry suppliers Those interested in at tending or exhibiting should contact KoAnn Tingley Conference Coordinator Seminar Division Miller Freeman Publications 500 Howard Street San Francisco CA 94105 Phone 415 995 2426 FAX 415 543 0256 Hyperspace DOS Hyperspace Z System is a CP M 2 2 compatible disk operating system for HD64180 and Z280 compatible systems which includes ZCPR 3 3 ZRDOS 2 0 and sample BIOS for 64180 machines The Hyperspace Z System features a large 57 25
9. 1 track Get sector Setup sector value to compute bank Save for later Makes it almost too easy Skip over the 4 16K tracks that make up the 64k CP M system Move low order track bit to high order Sector value to select addr In bank Get bank number Turn on led Select bank Into lower 32K addresses Each sector Is 128 bytes Multiply by 128 to get sector address 4 8 16 32 64 128 Number of bytes to move 1 sector Point to destination of data Local Stack Area Only 1 level required j 2333r2222 End of modified inserted code 222 22zzzzszz2azzzzzzzzzzazzz222 33 RA a E EEE A SS St a eed ve wsus we ve ve vs we we ee we Ys We wo Ve Ye Ve Vo We we we ws e We we we We We we we Ve Vo we Ve Vo we ve we we Ve we ve we ve ve ve ve ve ve we Listing 4 NOT i XOR A Clear 5380 registers SCSI init OUT NCRICR A ae OUT NCRMR A o gt OUT NCRTCR A 3 OUT NCRSER A Srs ENDIF 3 End of HD initialization XOR A Patch out old CP M message LO CPMMSG A LO HL LOGMSG Display signon message CALL PUTS LD HL ZBOMSG CALL PUTS LO HL ORIVESTDATA Init drive type data LO OE ORIVESTYPES LD BC 8 OEFW LDIR8O jsessssszss Insert modified code as shown below 2 s s s 2sz ssc 2s 22 2 LD A 02 First MDISK bank sys amp dir track OR MD I SKLED Turn on led OUT MDPORT A Select bank LD DE MOENTRY 3 MISK entry LO C 32 Length of entry LO HL 4000H Point to first direc
10. 21 a my ideas for an enhanced ZCOM It seemed however that he was much too busy at the time with other products to give any at tention to ZCOM so I decided that my next project after ZC PR33 would be a program that I tentatively called Dyna Z This would be a dynamic Z System an operating system whose con figuration could be changed on the fly Dyna Z would be useful in several ways One could normally run a system with all the standard ZCPR3 modules except an IOP input output package giving one a good set of ZCPR3 features for normal operations When one wanted to make use of an IOP like Joe Wright s superb NuKey keyboard redefiner program a load alias would first check to see if an IOP space was available in the system If so NuKey would be loaded If not the alias would switch the operating system to one that did include an IOP and then load NukKey One would sacrifice the 1 5K of TPA transient program area the memory available for a program to work in only while one needed the benefits of NuKey On the other hand when one invoked a command such as WordStar 4 or a spreadsheet that required a large TPA an alias for that command would first switch to a Z System with no IOP or RCP increasing the TPA by 3 5K compared to the full Z System One could even drop the FCP 0 5K and or the NDR 0 5K typically When the memory hungry program was finished running the remainder of the alias script would reload the stan dard
11. DSM is the maximum data block number 1 not counting the one 16k system track we re reserving for the operating system and directory This value will vary according to the number of chip sets installed from 87 for one chip set to 471 for all 4 chip sets By earlier setting the CHIPS equate to the number of chip sets you will use these calculations will be made automatically during assembly of the BIOS The Directory Maximum 1 DRM is the total number of directory entries allowed 1 Since we selected 128 as the maximum number of entries DRM will be 127 ALO and AL are really a single 16 bit word representing a bit map showing the data blocks reserved for directory entries Since each directory entry is 32 bits and we need space for 128 entries we need 32 31 oe Yeye us ve ve ve we ve ye ve we amp Listing 3 PHYTAB DEFB DEFB DEFB DEFB DEFB 222322238322 vsus we ve ve DEFB DEFB DEFB DEFB DEFB etc up through drive DEFB DRYRADR DEF W DEFW DEFW IF DEFW END IF DEFW END DEFW DEF W DEFW 232232335333 1 000H SSDD48 Ok 1 011H SSDD48 OH 1 033H SSDD48 OH 2 044H OH OFFH Floppy drive A Floppy drive B 1 022H SSOD48 OH Floppy drive C Floppy drive D Special floppy drive E Insert modified code as shown below s sss2s22eesz2zs2252825 is Irrelevant 0 0FOH 0 0 SELERR FLOPPY DISKE HARD D I SK DRYRS IF NOT HARD D1SK SE
12. Immediately after a cold boot and before any IOP is loaded the IOP memory segment has a dummy IOP in place Use the ZCPR3 SHOW utility to determine the address of your IOP If you are using an AMPRO BIOS modified as shown in this article then that address is ECOOH Using the debugger enter the following commands A0 gt D0T lt ret gt MECOO FIFF 100 AQ gt SAVE 6 DUMMY IOP This will move the 1 5K dummy IOP image residing in Memory between ECOOH and FIFFH down to 100H through 6FFH After exiting the debugger six 256 byte pages are saved to the filename DUMMY IOP If you perform any changes to your BIOS which will change the location of the internal BIOS jump table you will have to create new copies of your NUKEY IOPs and the DUMMY IOP If you attempt to load a previously created IOP after BIOS changes which caused the BIOS to change size the IOP will almost certainly cause the system to hang Customizing NuKey NuKey has three built in features which can be customized by the user For nearly all applications NuKey will run right out of the box and customization will not be necessary But for those times you need them having the ability to change these three parameters can be a life saver The first parameter is called FUNDEL Some terminals tran smit their function keys as fast as their current baud rate will per mit while other terminals deliberately insert a time delay between the function key characters By c
13. Those four sectors must be contiguous For a specific file allocation units do not have to be contiguous but they usually are By its construction the directory must be contiguous Therefore the following algorithm was used to predict when and where the next disk read was to be e When the last record of the current read buffer is read by the calling program increment the sector number and the track number if required then read this sector into the read buffer Notice this algorithm assumes a file will be accessed serially CP M supports random access files and this algorithm may ac tually degrade performance for randomly accessed files This risk is acceptable because programs that perform random access are very rare Notice a predictive read ahead may fetch a sector that is never used Concurrent Processing Concurrent processing in this context means the floppy disk controller and the microprocessor are simultaneously performing useful work The original single density system had almost no concurrent processing A simple foreground background scheme was im plemented to support concurrent processing All applications programs run in the background and floppy disk controller routines run in the foreground All foreground routines are in voked by an interrupt from the floppy disk controller When an interrupt occurs the processor interrogates the floppy disk con troller and determines which foreground task to run If there is u
14. Under NuKey you can have as many different keychanger IOP s as you desire For example my SYS IOP system keychanger translates my keyboard s ERASE key into the string CLS which is the Z System command to clear my screen When I run my word processor I load WP IOP which translates by keyboard s ERASE key into G control G which is the Wordstar compatible erase character function When I use the modem program the MODEM IOP allows me to send my name and password to sign on to a remote computer with the touch of two keys To make things confusing NuKey is more than a keychanger NuKey is a string changer This means that NuKey can not only translate single character keys into a string of one to 500 characters but it can also translate keys which them selves generate from one to 15 characters into another string of one to 500 characters Those of us who have CRT terminals which generate more than one character when the function and cursor keys are pressed can really appreciate this feature of NuKey Almost any character or string of characters generated by a keyboard can be translated into another string of characters by NuKey Another very powerful feature of NuKey is the extend key The extend key can almost be thought of as a special keyboard shift key Using the extend key you can assign a translation to any key on your keyboard but the translation will only take place if
15. disks for some CP M computers which require absolutely no installation and are capable of reconfiguration to change ZCPR3 s memory requirements Bootable disks are available for Kaypro 280 and Morrow MD3 computers Z80 Turbo Modula 2 We are proud to offer the finest high level language programming environment available tor CP M compatible machines Our Turbo Modula 2 package was created by a famous language developer and allows you to create your own programs using the latest technology in computer languages Modula 2 This package includes full screen editor compiler linker menu shell library manager installation program module library the 552 page user s guide and more Everything needed to produce useful programs is included Turbo Modula 2 is fast Sieve benchmark runs almost three times as fast as the same program compiled by Turbo Pascal Turbo Moduia 2 is well documented Turbo s librarian is excellent Micro Cornucopia 35 BGli Backgrounder 2 BGii adds a new dimension to your Z System or CP M 2 2 computer system by creating a non concurrent multitasking extension to your operating system This means that you can actually have two programs active in your machine one or both suspended and one currently executing You may then swap back and forth between tasks as you see fit For example you can suspend your telecommuni cations session with a remote computer to compose a message with y
16. little Z editor has released LLDR a version of LDR with library support This program completely replaces LDR the standard module loader program used to load new ENV Z3T RCP FCP NDR and OP operating system code segments It does everything LDR did but adds one new very important feature It can load the modules from a library ENV and Z3T modules in particular are very short one or two records and it was very inefficient use of disk and directory space to have them sitting around as individual files Now all the system files can be collected together in a single LBR file or several if you prefer LLDR s syntax can be expressed in general form as follows LLOR library La8R i lt list of modules to load gt If the optional library specification is omitted then it performs just like LDR If all the system modules are placed in a file called for example SYS LBR then one might invoke LLDR renamed to LDR as follows LOR SYS SYS ENV DIMVIDEO Z3T DEBUG RCP SYS FCP NUKEY 10P pa Besides the saving in file space and directory entries there is another nice side benefit of using LLDR in this way it is much faster Since only one file SYS LBR has to be opened by the operating system there is only one directory search and loading the entire collection of modules takes little more time than loading a single one did with the old LDR program Thanks Paul for another nice progra
17. many others Continued on page 40 5 A Double Density Floppy Disk Controller Algorithm for the CP M Operating System by Donald C Kirkpatrick Have you been looking longingly at those new 1 2 Megabyte floppy disk drives wishing you could upgrade your system When I started building my CP M system from scratch one thing was certain it would have to read standard 8 exchange format disks But I always knew that some day I would want to upgrade to a double density format When I finally made my move I set two goals increase the storage per disk as much as possible and improve the system throughput with concurrent processing When you decide to make your move to the higher density drives the ideas design considerations and compromises problems and algorithms given here should help ease your transition Believe me the performance increase is well worth the time invested The ideas presented here are of particular interest to those of you who are upgrading your 51 4 systems With two exceptions the newer 5 1 2 Megabyte drives for example the Panasonic JU 475 are electrically identical to the older double sided 8 drives The two exceptions are the number of tracks on the 1 2 Megabyte drives has been increased from 77 to 80 and there is now a motor on control If either of these differences change any result that will be noted at the appropriate time My system has two eight inch single sided disk drives which ca
18. surpassing any disk operating system on the market today Get our catalog for more information there s four pages of discussion regarding ZCPR3 explaining the benefits available to you by using it 2 System Z System is Echelon s complete disk operating system which includes ZCPR3 and ZRDOS It is a complete 100 compatible replacement for CP M 2 2 ZRDOS adds even more utility programs and has the nice feature of no need to warm boot C after changing a disk Hard disk users can take advantage of ZRDOS archive status file handling to make incremental backup fast and easy Because ZRDOS is written to take full advantage of the Z80 it executes faster than ordinary CP M and can improve your system s performance by up to 10 Installing ZCPR3 Z System Echelon offers ZCPR3 Z System in many different torms For 49 you get the complete source code to ZCPR3 and the installation files However this takes some experience with assembly language programming to get running as you must perform the installation yourself For users who are not qualified in assembly language programming Echelon offers our auto install products Z Com is our 100 complete Z System which even a monkey can install because it installs itself We offer a money back guarantee if it doesn t install properly on your system Z Com includes many interesting utility programs like UNERASE MENU VFILER and much more Echelon aiso offers bootable
19. 15 Market Street Cirencester Glos GL7 2PB ENGLAND Needs Northstar Help I have and use an Ampro Little Board two Heath H89s with hard sector and three Northstar Horizons with hard sec tor I would like to see anything on the Horizon as I have little documentation on them Maybe you could provide a good neighbor helper list like Echelon has with addresses of individuals willing to share some expertise on some of the antiques that are still strong For a specific one of the Horizons had a fatal HD crash It is gathering dust because I don t know how 40 to format and initialize an RD7 Northstar hard disk environment G N Editor We have had several requests Jor Northstar help and G N s suggestion regarding a helper reference list SMUG also has a similar list would be part of our helping each other by sharing our knowledge If you are willing to have your name and area of expertise either published in TCJ or available in the office on a on request only basis send us the information and we ll act as a clearinghouse If you have specific questions send us the questions with permission to publish with your name and address for direct reply from our readers HTPL amp Turbo C HTPL is a great idea since I program in MOD2 F83 Forth and 80186 Assembly X16B I got Hawthornes 8086 Assembler nice simple elegant I m looking forward to issue 30 especially more about the Tiny Giant 68000
20. I get the expression parser in place all the high DEVELOPMENT 88 or paea e SOFTWARE TEE N SAN FRANCISCO FEBRUARY 17 19 1988 The most comprehensive seminar ever heid on the practical aspects of software development You can choose from 90 lectures by the foremost software development experts attend three days of technical workshops and view exhibits by industry suppliers This is an event tailored to your needs Don t miss it A MAJOR TECHNICAL CONFERENCE gt To register write to Miller Freeman Publications 500 Howard Street San Francisco CA 94105 415 397 1881 level keywords will fall in almost automatically Since I m only a hobbyist running open loop I welcome any comments about what I m doing wrong or what would be neat to include Those interested in 32000 hacking should also contact Richard Rodman 1923 Anderson Road Falls Church VA 22043 He has started a small newsletter for 32000 hackers which he currently gives free of charge It is to be a forum on the creation of a public domain operating system and a focal point for ex change of 32000 schematics software and information He is starting an inventory of P D software that anyone can get for 8 a disk The first volume contains my cross assembler my Z80 assembler and 32000 source code for transcendentals complex math complex transcendentals a disassembler and a math intensive orbital game program in assembly If anyone
21. LINE CODE INCTT MOVE W COUNTI A5 DO0 TEST OLO BEQ S INCT2 IGNORE IF Z SUBQ W 1 COUNTI A5 0 amp C COUNTER BNE S INCT2 iNO ACTION IF NZ ST FLAGI 1 A5 SET FLAG IF Z MOVE W LOAD1 A5 COUNT1 A5 RELOAD COUNTER INCT2 RTS SUBROUT I NE LEA COUNTERI A5 AO POINT TO STRUCTURE BSR SOF TCOUNT LEA COUNTER2 A5 AQ 2 BSR SOF TCOUNT LEA COUNTERS A5 AO 5 3 BSR SOF TCOUNT RTI A soft counter is defined as a data structure in memory which has a counter that is counted down each time a timer interrupt oc curs There is a reload value to reload the count after it is counted down and a flag that is set when the count has been counted down to zero This is a flexible arrangement that can be used for one shot timers continuous timers or other timer types First clear the flag to indicate that the timer is about to start Then if it is to be continuous set the reload value If the time is to The Computer Journal Issue 30 be a one shot timer then the reload value should be zero To start the timer set the count to a nonzero value The timer will then count down on each time tic until it reaches zero At that time it will set the flag To find out if the time has expired you check the flag at convenient intervals Once the soft timer has been set and is runniing it will continue in the background almost like a har dware timer For long time intervals in the millisecond or second region this is a very low cost way to have many ti
22. PRINTER which taken together offer a significant support facility for Z System and CP M users whose interests are primarily in word processing Systems and 2 have different flavors and different audien ces The group that hangs out on System 1 tends to be less technical in orientation than the group on System 2 System 2 has no applications programs It is devoted entirely to operating system software including 4 megabytes of software to install ZC PR3 or ZCPR33 on virtually any 8 bit computer System 2 also has a named directory called OPSYS devoted to non ZCPR operating systems as well as BDOS replacements other than ZR DOS which is not public domain System 1 has the dBASE files the Turbo Pascal programs and the writer s aids It also tends to attract more vigorous debate than System 2 Should the TCJ subscribers directories whet your appetite you can opt for full membership with access to the entire 144 megabytes on both systems For full membership send a check for 35 payable to Richard Jacobson accompanied by pertinent information name address work and home phone num bers to Richard Jacobson Lillipute Z Node 1709 N North Park Avenue Chicago Illinois 60614 After I receive your membership fee and application and after your initial login I will set you for access to the entire 144 megabytes of software on both systems W 41 Back Issues Available Issue Number 1 e RS 232 Interfac
23. a solid state disk drive com plete with a system track As the driver routines include the modification of the CP M Disk Parameter Block you may wish to review Thomas Hilton s article Disk Parameters in Issue 27 of TCJ for more detailed information on the CP M DPB There are several approaches to sof tware RAM disk drivers We have chosen a very direct approach which is to add the driver routines directly to the AMPRO BIOS This approach takes advantage of existing BIOS routines creates the most compact and integrated code and is not troubled by possible interactions with programs such as keyboard redefinition utilities that relocate themselves into high memory In order to modify the BIOS however you must first have a copy of the BIOS source code which is available directly from AMPRO as you cannot add the new routines directly to the BIOS HEX file or to the operating system The AMPRO BIOS MDISK requires the use of AMPRO BIOS version 3 0 or above which offers much greater capabilities than the earlier BIOS versions Although the AMPRO BIOS is written in 8080 assembly language it actually uses many Z80 in structions These instructions are entered as data words DW in order to fool ASM COM into thinking that they are merely data so that it doesn t attempt to process them Since the BIOS is really Z80 code and since we use Z80 code in the MDISK driver routines we have chosen to present the driver routin
24. come by The system is causing almost as many problems as it is solving Several people are ready to go back to the old system because they have had so many problems Overall they would have little chance of surviving the computer s problem if it wasn t for my friend practically giving his time away to them For me it points up so many negative aspects of where the computer industry is at present Up until two or three years ago the in dustry either used computers within them selves or you had big companies supplying you with a guru computer whiz The suc cess of the PC sellers in convincing users that anyone can use them and especially program them is just now being felt The previous example is a good picture of the so called blind leading the blind For me doing business with companies it presents a special problem Before a company should buy any system their projected problems choices and solutions need to be fully outlined I find most businesses buying then asking later will it do what we need done When the topic of training or using consultants comes up the bottom line is cost and that usually means the lowest bidder Now when we talk about lowest bidders I usually remind people that the shuttle booster rockets are made by the lowest bidder and we all know what happened to the astronauts in that case Industrial com puters can kill too but typically they will just destroy your data and eat up your mone
25. e Extending Turbo Pascal Customize with Procedures and Functions e Unsoldering The Arcane Art e Analog Data Acquisition and Control Connecting Your Computer to the Real World Programming the 8035 SBC The Computer Corner Issue Number 22 e NEW DOS Write Your Own Operating Systern e Variability in the BDS C Standard Library e The SCSI Interface Column e Using Turbo Pascal ISAM Files e The AMPRO Little Board Column e The Computer Corner Issue Number 23 e C Column Flow Control amp Program Structure e The Z Column Getting Started with Directories amp User Areas eae SCSI Interface Introduction to Introductory e NEW DOS The Console Command Processor Editing The CP M Operating System e INDEXER Turbo Pascal Program to Create Index The AMPRO Little Board Column The Computer Corner Issue Number 24 e Selecting and Building a System e The SCSI Interface SCSI Command Protocol e Introduction to Assembly Code for CP M The C Column Software Text Filters e AMPRO 186 Column Installing MS DOS Software The Z Column e NEW DOS The CCP Internal Com mands e ZTIME 1 A Realtime Clock for the AMPRO Z 80 Little Board The Computer Corner Issue Number 25 gt Repairing amp Modifying Printed Circuits e Z Com vs Hacker Version of Z System e Exploring Single Linked Lists in C e Adding Serial Port to Ampro Little Board e Building a SCSI Adapter New DOS CCP
26. e Programming Style User interfacing and interaction e Patching Turbo Pascal Using disassem bled Z80 source code to modify TP e Choosing a Language for Machine Control The advantages of a compiled RPN Forth like language TCJ ORDER FORM Subscriptions 6 issues per year O New O Renewal S Expiration date Name Address l i l l l l l l City l l Peate a ates pg ee The Computer Journal Issue 30 Back Issues _ Six or more _ _ _ Signature Issue Number 29 Better Software Filter Design Writing pipable user friendly programs e MDISK Adding a 1 Meg RAM disk to Ampro L B part one e Using the Hitachi HD64180 Embedded processor design e 68000 Why use a nes OS and the 68000 e Detecting the 8087 Math Chip Tem perature sensitive software e Floppy Disk Track Structure A jook at disk control information amp data capacity e The ZCPR3 Corner Announcing ZC PR33 plus Z COM Customization The Computer Corner US Canada lyear 16 00 2years 28 00 All funds must be in U S dollars on a U S bank Check enclosed O VISA O MasterCard Card Total Enclosed tate ZIP The Computer Journal 190 Sullivan Crossroad Columbia Falls MT 59912 Phone 406 257 9119 Total News Software Development Conference
27. exceeded expectations SUS is intended for our customers who don t have easy access to our Z Node network of remote access systems At least nine times per year we mail a disk of software collected from Z Node Central to you This covers non proprietary programs and files discussed in our Z NEWS newsietter You can subscribe for one year six months or purchase individual SUS disks There s More We couldn t fit all Echelon has to offer on a single page you can see how small this typeface is already We haven t begun to talk about the many additional software packages and publications we offer Send in the coupon below and just check the Requesting Catalog box for more information hem Name Pree 1 ZCPR3 Core installavon Package 49 00 3 disks 2 ZCPR3 Utili es Package 89 00 10 disks 5 Z Com Auto Instal Complete 119 00 5 disks 2 System 6 Z Com Bare Minimum 69 95 1 disks 10 BGu nder 2 75 00 2 disks 12 PUBLIC ZRDOS Ptus by tset 59 50 1 disk 13 Kaypro Z System Bootable Orsk 69 95 3 disks 14 Morrow MO3 Z System 69 95 2 disks Bootable Disk 16 QUICK TASK Realtime 249 00 3 disks Executive 17 DateStamper file pmevdate 49 95 1 disk stamping 18 Software Update Service 85 00 1 yr sub 20 ZAS ZLINK Macro Assembier 69 00 1 disk and Linker 21 ZDM Debugger for 8080 ZB0 50 00 1 disk 064180 CPU s 22 Translators tor Assembier 51 00 1 disk Source code 23 REVAS3 4 Disassembi
28. language to demonstrate the concept The same principles can be used to multitask in almost any language but it will be more complex because more registers have to be saved and reloaded with each context switch You need to find out which registers are used by the language you are using when you write the swap routine The routines to start the system and to switch to the next task are prototypes that you change to fit your special application The examples show how to use the task switching The program presented here is in several parts There are three routines needed in your multitasking system There are two HTPL routines PROGRAM and NEXT and one assembly language routine SWAPTSK These are shown in Listing number 1 The versions here are for a system that has three tasks The main program gets things started NEXT changes to the next task 37 SAMPLE CODE potceen HTPL CODE FOR MULTI TASK i jee2sees SWAP TASK OLD NEW SWAPTSK MOYE L A4 Al NEW POINTER MOVE L A4 A0 OLD POINTER MOVE L A7 A3 RETURN MOVE L A4 A0 J SAVE PARAM PNTR MOVE L A7 A0 SAVE STACK PNTR MOVE L A1 A4 NEW PARAM PNTR MOVE L A1l A7 NEW STACK PNTR JMP A3 RETURN TO CALLER HTPL NONPREEMPTIVE MULTITASK these must be contiguous and in order tong tskOp tskOr tskIp tskir tsk2p tsk2r tsk3p tsk3r long tskpn tskid program 512 allocate 512 Itsklip 512 allocate 508 taski 14 4 Itskir 512 allocate 512 tsk2p 512 allocat
29. learning to hate the PCs completely We 48 THE COMPUTER CORNER A Column by Bill Kibler used a lot of PC programs in the course but not once did I feel those programs were better or faster than those I had used on CP M or the ST s GEMDOS Hopefully by the time you read this Atari will have released the new MEGA ST and a more business like product will be on its way to changing Atari s image I got into one discussion at the SOG just on that problem the idea that Atari only makes game machines Now don t get me wrong the ST is one super great game machine but let s see why To be truly a good game machine you need speed good graphics ability to do animation lots of memory no paging please and low cost In several ways those items are available on plenty of machines but to equal the standard design of the ST a clone would cost almost twice as much When looking at game ability business use in many ways is rather simple or hardly taxing of the system For industrial use the PC s operating system and to some extent the CPU design are not intended for multitasking real time event handling like the 68K is While at the SOG Art and myself had several discussions with FORTH and STD bus users about writing articles for the Computer Journal I have since talked with the person who changed to 68K CPU and he is going to try and explain why they switched One reason why I like the STD bus is just that ability to ch
30. list of files is an LBR file then the rest of the list is taken as a specification of the members of that library to be in cluded in or excluded from the search As with individual files these files can be unsqueezed or uncrunched on the fly As if this were not enough JetFind has about a dozen mode control options that define how it performs the search and what it does with the text identified by the search Here are descriptions of just a few Cc This option just counts and dispiays the number of matches without showing the matching lines of text N The lines containing matching text wil be numbered in the listing to make it easy to find them with an editor Rmn This specifies a display region m and n are each digits from 0 to 9 For each iine containing a match to one of the patterns the previous m lines and following n lines will also be inciuded in the display to provide context Case will pe ignored so that a and A will be considered to matcn 8 Begin displaying the text as soon as the first match has been found y Reverse the test and display only lines that do not match any of the specified patterns T Type the tile extracting it from a Ilbrary and or uncompressing it as required With these and other options not listed above JetFind can be made to perform many tasks besides searching such as typing files extracting files from libraries splitting off parts of files and displaying files in a directo
31. long Sixteen bytes form a table of allocation unit numbers owned by the file The other sixteen bytes contain the name and other housekeeping items Four directory entries fit in to one 128 byte record The standard CP M single density system reserves two allocation units 2K for 64 directory entries In the double den sity format used here the directory size is increased to 128 entries since the disk size is slightly more than double Because I chose an allocation unit size of 4K the directory will fit into one allocation unit The directory entry allocation table contains unit numbers assigned to that file When the highest allocation unit number on the disk is less than 256 each allocation unit number fits into one byte and each directory entry table holds sixteen allocation unit numbers When the highest allocation unit number is greater than 255 it takes two bytes to store one number and each directory entry table holds only eight allocation unit numbers Now you know why the allocation unit size was changed to 4K the maximum allocation unit number will not exceed 255 not so with 1K or 2K units on a 684K disk When a file has less than six teen eight allocation units the directory entry table will have some empty entries Such an unused entry contains a 0 since allocation unit 0 is always dedicated to the directory never a file When a disk is full it will be for one of two reasons either there is no free allocation unit to ass
32. m b o o H e 22 I n D m ee e e m oo q n e n SP ta i a 4 zs meee Ss ae Se a X a o m a n ar a um mau gt ama m aw am w gt am a aa w m e oo 7 a mws s mw o ue e ue o m ee a a UNEEN Wy Programming User Support as SSS Applications Issue Number 30 Double Density Floppy Disk Controller An Algorithm for the CP M Operating System ZCPR3 Implementing IOP Support for the Ampro BIOS 32000 Hacker s Language MDISK Part 2 A One Megabyte RAM Disk for the Ampro L B Non Preemptive Multitasking Software Timers for the 68000 Lillipute Z Node A Remote Access System for TCJ Subscribers The CP M Users Corner ISSN 0748 9331 THE COMPUTER JOURNAL 190 Sullivan Crossroad Columbia Falls Montana 59912 406 257 9119 Editor Publisher Art Carlson Art Director Donna Carison Production Assistant Judie Overbeek Circulation Donna Carlson Contributing Editors Joe Bartel Bob Blum C Thomas Hilton Bill Kibler Frederick B Maxwell Jay Sage Kenneth A Taschner Entire contents copyright 1987 by The Computer Journal Subscription rates 16 one year 6 issues or 28 two years 12 issues in the U S 22 one year in Canada and Mexico and 24 sur face for one year in other coun tries All funds must be in US dollars on a US bank Send subscriptions renewals or address changes to The C
33. most useful tool and safeguard If you re one of the many Z 80 computer owners that lack the hardware necessary to maintain time and date information then Ztime 1 may be for you It is a complete real time battery driven clock board that is installed by inserting it in place of the Z80 chip of your computer s main logic board The Z80 chip is then placed in the socket provided on the Ztime 1 board If you have ever run out of symbol table space during an assembly the folks at SLR Systems can help you They have recen tly released the latest version of their now famous Z80ASM assembler It has extra logic incorporated that will begin using tables on disk if memory fills to capacity Outside of porting CP M Plus to different machines my favorite project is comparing CP M compatible operating systems I have successfully implemented three out of the four packages that I have been able to find I think you will be just as excited by the results as I am I could go on and on my list is far from empty but at this point I think it s time to listen for a while Please let me hear from you E if MDISK Part 2 Software Drivers for Ampro RAM Disk by Terry Hazen amp Jim Cole Introduction In this second part of our series on the MDISK add on megabyte RAM disk for the AMPRO Z80 Little Board we will present the software drivers that are added to the AMPRO BIOS in order to enable the Little Board to use the exten ded RAM as
34. proper bank by outputting a byte to the control port Move the data to or from the RAM disk depending on whether a read or write operation is being performed Then output another byte to The Computer Journal Issue 30 the control port to bring Bank Page 1 back into place Finally return to the calling routine This completes the sequence and returns you back to a nor mal C PM configuration i Creating Your New MDISK System The modified BIOS we have created isn t useful until it has been assembled and combined with the rest of the operating system Start by renaming your modified BIOS to MDBIOS ASM assemble it with ASM and place a copy of it on a fresh system disk Create the system image of your old system as follows assuming that you are creating an all floppy 59k system AO gt ZMOVCPM 59 lt RETURN gt CONSTRUCTING 59K CP M vers 2 2 READY FOR SYSGEN OR SAVE 41 CPM59 COM AO gt SAVE 41 OLO SYS lt RETURN gt Note that the CP M size number in this case 59 must match the MSIZE value in your modified BIOS Now use DDT to create a new system image file MDISK SYS AQ gt DOT OLD SYS DOT VERS 2 2 NEXT PC 2A00 0100 1MDB 10S HEX R3980 NEXT PC 2A00 EE00 60 AO gt SAVE 49 MDISK SYS Use one of the following read offset values according to the size of your system MSIZE k Offset 59 3980H 58 3080H 57 4180H 56 4580H Finally use SYSGEN to install the new system on a fo
35. software items Here are a few I ve spent some time with the latest 8 bit single board com puter being produced by Micro Mint This little barn burner smaller than a mini floppy disk drive sports the HD64180 the newest 8 bit chip being produced by Hitachi I m told that this device is at least as powerful as an 8 MHZ Z80 while offering a much higher level of integration that includes I O ports and other features that normally require many external devices Even thought DRI has placed CP M Plus on the mature list and as such will no longer actively support it I am continuing to port it to different computers My most recent adventure is with the Intercontinental 8 bit S 100 master board on board memory Management and many other performance features make the ICM board a natural for CP M Plus Among the top ranking features of CP M Plus is its capability to automatically time and date stamp files at each ac cess This feature is especially important to me because I have the untidy habit of not religiously tracking my disk files during a heated development session I wait for the project to conclude before trying to make good sense out of my files and then sometimes have trouble recalling the order in which I created them and most importantly which is the most current Until Plu Perfect Systems began to sell DateStamper there was no sof tware available to add this desirable feature to CP M 2 2 I ve used DateStamper and have found it a
36. space savings to the 1 5k IOP reserved memory but you are allowed an unlimited number of 1 5k IOP segments This adds great versatility to your BIOS Recently Joe Wright a prominent member of the Z System community proposed an extension to the basic IOP concept Joe s proposal was to leave the device drivers in the BIOS and to have the IOP act as a front end or pre processor to BIOS device driver calls With this method the Jump Table at the beginning of the BIOS was modified to direct console printer reader and punch calls to the IOP instead of to their respective routines within the BIOS When a call is made to the BIOS for one of these I O routines the BIOS first passes the call on to the IOP The IOP will perform some pre processing and then pass the call on to the originally intended routine in the BIOS This is how Joe Wright s NuKey works NuKey is an IOP which performs console keyboard key re definitions With NuKey you could program your function keys to be translated into a string of 1 to 15 characters Let s say that you use NuKey to translate your CRT s function key F1 to the string DIR lt return gt Let s also say that your CRT sends ESCAPE A when the F1 key is pressed When NuKey is running all console input requests are directed through the NuKey IOP first NuKey is monitoring all characters coming from your keyboard Suddenly NuKey sees ESCAPE A come in Instead of passin
37. stamp your CP M files with creation modification and access times 49 e Echelon Z Svstem Software ZCPR33 full system 49 user guide 15 ZCOM automatically installing full Z System 70 basic package or 119 with all utilities on disk ZRDOS enhanced disk operating system automatic disk logging and backup 59 50 DSD the incredible Dynamic Screen Debugger lets you really see programs run 130 SLR Systems The Ultimate Assembly Language Tools Assemblers Z80ASM 280 SLR180 HD64180 SLRMAC 8080 and SLR085 8085 Linker SLANK Memory based versions 50 Virtual memory versions 195 o NightOw Advanced Telecommunications MEX Plus automated modem operation 60 Terminal Emulators VT100 TVI925 0G100 30 Same day shipping of most products with modem download and support available Shipping and handling 4 per order Specify format Check VISA or MasterCard Sage Microsystems East 1435 Centre St Newton MA 02159 Voice 617 965 3552 9 00 a m 11 15 p m Modem 617 965 7259 24 hr 300 1200 2400 bps password DDT on PC Pursuit First some history In the summer of 1984 Joe Wright was reflecting on the difficulty of converting stock CP M 2 2 systems to ZCPR3 and wondering if an automatic method could not be developed Rick Conn apparently opined that such a thing would not be possible Joe did not ask me we did not know each other at the time but if he had I
38. system Piugs into Z80 socket Distributors Argentina Factorial S A 41 0018 Australia Current Solutions 03 227 5959 e Brazil Computadores Compuleader 41 262 4866 Canada Tri M eca 434 0028 Denmark Danbit 03 66 20 20 Finland Symmetric OY 358 0 585 322 France Egali Plus 1 4502 1800 Germany West IST Elektronik Vertribes GmbH 089 6 5 5 e teraet Alpha Terminais Ltd 03 49 16 95 Spain Hardware amp Software 204 2099 Sweden AB Akta 08 54 20 20 UK Ambar Systems Ltd 0296 435511 USA Cortact Amoro COMPLUTERS INCORPORATED 67 EastEvelyn Avenue Post Office Box 390427 Mountan View CAGAOSS 6115 230e TLX AM The ZCPR3 Corner by Jay Sage After the tremendous effort I put into producing my last column and ZCPR33 before leaving on summer vacation I was really burned out I hardly touched the computer or even thought about programming all summer This was quite remarkable since for months I had practically lived in front of that computer screen and thought I would have severe withdrawal symptoms if I didn t get my usual daily fix I was glad the last issue of TCJ came out a bit behind schedule because three weeks ago I really couldn t think of anything to write about for this column Then the bug struck again as I knew it would eventually My mind exploded with ideas and as in the past I again have far more things to talk about than I will have the energy or tim
39. the extend key was pressed first For example you can use NuKey to allow a control key such as control S to be passed unchanged but be translated to some other character or string only if the extend key was pressed before the control S was pressed This allows you to keep any or all keyboard keys un changed yet still have a complete set of definitions assigned to them The translation to the special definitions will only take place if the extend key is typed first The Details NuKey requires a Z80 compatible microprocessor This in cludes the 64180 and the NSC 800 NuKey also requires that you be running ZCPR3 and that your BIOS supports the implemen tation of IOP s as described in the Echelon publication ZCPR3 and IOPs If you followed my BIOS modifications in the first part of this article then your BIOS does conform to this requirement NuKey also works with Echelon s Z Com auto install Z System package as well as their bootable Z System disks for Kaypro and Morrow and Micromint s SB 180 As distributed NuKey is in COM file form NUKEY COM 16 can create an unlimited number of personally customized IOP s for your every application NUKEY COM is a ZCPR3 utility but does not have to be installed on most systems The owners manual does state that NUKEY COM may lock up some systems If this happens on your system just install NUKEY COM like you do most other ZCPR3 utilities with the Z3INS pr
40. to be loaded is compiled from its source The user is completely free to repair or embellish any part of the system at any time This is a vital feature because there is no such thing as a program that is good enough to be immune to shortcommings that demand correction The Computer Journal Issue 30 Another philosophical point of this system has to do with memory usage Because of a long history of cramped addressable memory it has become a universal custom to use disks as memory emulators We even have RAM disks that use memory to emulate the memory emulator Now that we have 68000 and 32000 processors we can use the novel approch of using memory as memory and using the disks to store things Another point is clutter reduction A long time ago I craved to get my fingers on a relocating assembler and linker but now af ter some seasoning I have found that the OBJ files and other in termediate files produced by compilers and assemblers constitute an obstacle course that impedes progress It forces extra activities to keep track of the files It requires constant editing of global lists It requires extra commands to do the inking etc It requires more editing of batch files It forces more disk changes due to full disks It also slows down the actual compilation My Z80 to 32000 cross assembler compiles an executable file twice as fast as the fastest linker that I have ever used and many times as fast as the linkers that do enough th
41. to support Echelon and the small number of other companies still developing 8 bit software by pur chasing their products They are the only hope for the sustained vitality of our 8 bit world If we don t buy the products they of fer the creative programmers who have not already done so will have no choice but to abandon Z80 programming in favor of the more lucrative IBM compatible market Check the ads in The Computer Journal and support the companies that advertise there Do not make regular use of illegitimate copies of their sof tware buy your own Unfortunately no one is getting rich on 8 bit software I did not keep a record of the time I spent on ZCPR33 so I cannot calculate accurately the effective hourly rate but a rough estimate 20 indicates that babysitting would probably have been a better way to make money In fact my greatest financial reward probably came from the money not spent on babysitters as a result of staying home programming instead of going out While reflecting on these issues I thought I had a brilliant idea put together a transportable computer and actually hire myself out as a babysitter That way I could get paid not only for the commercial products like ZCPR33 but for all the public domain programs as well Unfortunately on more careful con sideration I noted some serious defects in this scheme First of all how many people would hire me to sit night after night until 2 or 4 in the morning And
42. version of Z System One would hardly know that the operating system had been different while WordStar or the spreadsheet was running Thus Dyna Z would not only overcome the major disadvan tage of ZCOM but would also overcome the only intrinsic disad vantage of ZCPR3 the loss of TPA space A minimum Z System would use only 0 75K plus the autoinstall overhead reduced to a mere 0 25K a very small sacrifice for all the benefits that Z System offered And in a real pinch for TPA one could even drop out of Z System temporarily and run standard CP M with its maximum possible TPA Using SUBMIT even this could be done with a script I was delighted this summer when Joe Wright called on the phone to discuss his plans for New ZCOM It was the first I knew that he had taken up the project and I found that he had already made great progress Many of the features I had planned for Dyna Z were already implemented and Joe was eager to incor porate the rest Our partnership was born And it is a perfect par tnership for me Joe is doing all the work I would have been excited enough just to see the Dyna Z features in NZCOM but Joe has done much more than that He has made the process of building a system of your choice about as easy as it could possibly be You simply edit NZBAS LIB a text file describing the system configuration you want and assemble all the individual components CCP DOS RCP FCP etc to Microsoft format REL files NZ
43. who would want a babysitter who wouldn t notice the house burning down until the power went out on his computer screen Basically I think it is fair to say that all of us even those like Joe Wright who depend on it for their livelihood are in the 8 bit programming business because we love it Even for the non professionals like me there are reasons why some financial com pensation is important While we may derive enormous en joyment and excitement from programming our families do not but if it brings in a little extra spending money that the entire family can share they are much more tolerant of the long hours spent in front of the CRT or on the telephone helping users with problems New Commercial Z System Software As a transition from my soap box remarks above I would like to begin the technical discussion with a review of some ex citing developments in commercial Z System software WordStar Release 4 The most exciting development in a long time is the ap pearance from MicroPro of WordStar Release 4 CP M Edition As far as I can remember this is the first new CP M product from a major software house since Turbo Pascal version 3 came out several years ago and it is the only product ever from a major vendor that supports Z System I am thrilled at the official recognition this bestows on Z System For the season s kickoff meeting of the Boston Computer Society s CP M Computers Group we had representatives fr
44. 80 computer presently running CP M 2 2 In minutes you can be running ZCPR3 and ZRDOS on your machine enjoying the vast benefits includes 80 utility programs and ZCPR3 The Manual 169 00 2 Tools 4 disks A bundle of software tools individually priced at 260 total Includes the ZAS Macro Assembler ZDM debuggers REVAS4 disassembler and ITOZ ZTOI source code converters HD64180 support PUBLIC ZRDOS 1 disk 59 50 If you have acquired ZCPR3 for your Z80 compatible system and want to upgrade to full Z System all you need is ZRDOS ZRDOS features elimination of contro C after disk change public directories faster execution than CP M archive status for easy backup and more 1 disk The premier debugger for your 8080 Z80 or HD64180 systems Full screen with windows for RAM code listing registers and stack We feature ZCPR3 versions of this professional debugger Quick Task 3 disks 249 00 280 HD64180 multitasking realtime executive for embedded com puter applications Full source code no run time fees site license for development Comparable to systems from 2000 to 40 000 Request our free Q T Demonstration Program 2 System OEM inquiries invited Visa Mastercard accepted Add 4 00 shipping nandiing in Nortn Amenca actuai Echelon Inc cost elsewhere Specity disk format 885 N San Antonio Road Los Altos CA 94022 415 948 3820 Order line and tech support Telex 4931646 If you are uncomfortable ma
45. AL PORTS 250 K RAM S12 OB Km OPTIONS vad CPU 5 95 360 K 790 K 12 M8 UPTO 198K a EPROM taw NOMRAM BATTERY BACKED RT CLOCK Little Board PC World s smallest PC and CMOS too MOUNTS PC COMPATIOLE 95 ROMS Development Chassis PC Known Good PC bus project development environment for Little Board PC not included CMOS Video Controller 4 mode CMOS video controller for Little SCSI Memory Controller SCSI controller for fixed and removable volatile and non Board PC rom 9495 Bookshelf System Modules PC compatible Little Board PC systems Single and Multi User Little Board 186 systems Little Board Plus CP M systems SCSI disk and tape expansion modules Floppy drive expansion modules mucrosolt Corp Little Board 186 High performance single board MS DOS system Project Board 186 Prototype adapter for 80186 based projects and products from 1 49 Expansion 186 Multi function expansion for Little Board 186 I O Serial Concurrent PC DOS Multi user multi tasking oper ating system for Little Board 186 supports up to four users INCLUDES CP M Little Board World s least expensive single board system Project Board 80 Prototype adapter for Z80 based projects and products Scsi lOP STD bus I O expansion adapter for any SCSI host system SCS Z80 Host Adapter SCSI host adapter for any Z80
46. COM COM then generates a system auto loader program fcr you automatically It will even allow you to clone an existing system accomplishing automatically all the complex processes I described in my last two columns JetFind Now I would like to switch back in time and describe a program that has been around for a while already but has not had the publicity I think it deserves It suddenly struck me the other day just how often and in how many ways I use JetFind yet how few people probably are aware of its existence JetFind by Bridger Mitchell is basically a text finding program It is something like Irv Hoff s publicly released 22 FIND COM which can search through a file for a specified text pattern But it goes orders of magnitude beyond that To begin with I should explain that JetFind operates in either of two modes interactive or command mode In interactive mode the program is invoked alone with no command tail It will then prompt the user sequentially for each piece of infor mation it needs The user can then live inside JetFind performing one search after another until he issues an exit command Alter natively a single search operation can be carried out by including all the necessary information on the command line Now for the capabilities of JetFind First of all JetFind is not limited to searching the text for only a single pattern at a time It can search for multiple patterns and each one can be either a simpl
47. EMBLED AND TESTED ONLY SHIPPED ON AN MS DOS 5 1 4 DISK z x x x Order Now VISA HC 503 254 2005 HAWTHORNE TECHNOLOGY 8836 S E Stark Portland Or 97216 Now that you have a working RAM command line parameters 1 A simplified setup utility SETUP B FILENAME EXT would copy previously set If you are using ZRDOS the utility SFA will set the file attributes otherwise you can use a public domain utility such as DA21 SETUP uses the ACOPY 2 option to copy all the files on FO that have F2 set to MDISK The drive user specification and 2 the filename specification are used to copy any other files specified on the command line The ACOPY S option instructs ACOPY to skip the copy if the destination desired utility files from drive FO and filename ext from drive BO The last command in the ALIAS is to display a directory of MDISK 1 gt A 2 gt ACOPY F ACOPY COM S 3 gt ACOPY F 2S 4 gt ACOPY 1 2 S 5 gt DIR For more information on ALIAS use see Jay Sage s ZSIG Corner column in issue 27 of TCJ Possible MDISK Enhancements The extended RAM on the MDISK board can also be used for purposes other than a RAM disk The control software is what turns these extended banks of RAM into a disk drive emulator With the ap propriate control software the extended RAM could also be used as a printer buf fer multiuser work spaces fast storage for re
48. Error Processing The calling program expects the BIOS to return a flag in dicating if a read or write is successful Because writes occur in the foreground and may be deferred the write routine always returns success The entire burden of an unsuccessful operation and error recovery falls upon the BIOS Most soft errors are caused by the read write head not being correctly located over the track on the floppy disk This type of error can be corrected by stepping off the bad track and re seeking the track This step on off is per formed automatically by the BIOS If after 15 retries the operation is still unsuccessful the BIOS reports the error directly to the system console and prints the status bytes provided by the floppy disk controller This allows the operator to determine the severity of the fault and what corrective action is required Determining the Density The method of automatically determining the density of a _ floppy disk is quite simple The floppy disk controller monitors the disk drive and informs the operating system when a new disk is inserted The operating system then instructs the controller to report back with the first sector ID it can find on the disk in double density mode If the ID read is successful then the disk is double density if the read fails then the disk must be single den sity Keeping Track of Unallocated Writes One key performance increase comes from carefully keeping track of writes to a newl
49. Guide to Serial Com munications by Joe Campbell Published by Howard W Sams ISBN 0 672 22584 0 A large book 655 pages which an swers most of the questions I had about baud rates UARTs CRC XMODEM interrupts and much more My only complaint about this book is that it wasn t here three years ago when I started digging out the facts about serial com munications Now PII read it cover to cover to fill in the gaps in what I picked up elsewhere Classified WANTED Dietary and Nutritional software and or books papers and resource information for use on an IBM PC ina public institution Low cost or public domain software with sour ce code preferred as they have an experience programmer available to modify and customize the programs The Computer Journal Box T 190 Sullivan Columbia Falls MT 59912 phone 406 257 9119 WANTED S 100 Boards and or documentation Contribute the S 100 material which you are no longer using to the TCJ S 100 resource archives Send material to The Computer Journal 190 Sullivan Columbia Falls MT 59912 phone 406 257 9119 WANTED WordStar Version 3 X for generic MS DOS which supports ASCII terminals Now that you ve upgraded to Version 4 0 get rid of your old no longer used version Contact The Com puter Journal 190 Sullivan Columbia Fails MT 59912 phone 406 257 9119 Data Compression Second Edition Techniques Applications Hardware amp Software Co
50. I ve got the K OS 1 but not the board yet I received Turbo C version 1 0 and the Integrated Environment serves the wants of Turbo Pascal Users interface a real improvement Paid 59 dollars for it The surprise was inside the front cover 295 for source code to the Run Time Library Adding the 150 toolbox for Turbo C the compiler environment is a little over 500 the price of Aztec C commercial version Ouch But Turbo C is good for a beginning C programmer like myself R S Miscellaneous Reader Comments I m using a Sanyo MBCS55 series with various add in boards and have a Taiwan clone that s hardly used What I d like to see in TCJ is do it yourself stuff 680X0 32XXX TI DSP RISC etc I m engulfed in MS DOS stuff in all the other magazines but unfortunately much of it is superficial I m interested in S 100 SCSI Z80 upgrades ZSystem TurboDOS Har dware Interfacing RBBS Systems ZNode SYSOP I use Osbornes Xerox 820s a Morrow MD 11 and SB180 w ETS I O expan sion and am currently playing with a National Single board 323372 I like your 8 bit OS articles and your embedded processor articles especially The series on SCSI was particularly helpful I would like to see more coverage of National s 32000 series I d like to see articles on the 68000 8748 Robotics Controllers C and Forth I m using Tandy M100 Sharp PC1600 SB180 ZRDOS and Macintosh Con tinue your ZRDO
51. II From Assembly Language Part 2 The State of the Industry e Lowering Power Consumption in 8 Floppy Disk Drives e BASE Part Three Issue Number 16 Debugging 8087 Code e Using the Apple Game Port BASE Part Four e Using the S 100 Bus and the 68008 CPU Interfacing Tips amp Troubles Build a Jellybean Logic to RS232 Converter 42 Issue Number 17 e Poor Man s Distributed Processing BASE Part Five e FAX 64 Facsimile Pictures on a Micro The Computer Corner Interfacing Tips amp Troubles Memory Mapped I O on the ZX81 Issue Number 18 eae Interface for Apple II Game ort The Hacker s MAC A Letter from Lee Felsenstein e S 100 Graphics Screen Dump e The LS 100 Disk Simulator Kit e BASE Part Six e Interfacing Tips amp Troubles Com municating with Telephone Tone Con trol Part 1 e The Computer Corner Issue Number 19 e Using The Extensibility of Forth Extended CBIOS e A 500 Superbrain Computer BASE Part Seven e Interfacing Tips amp Troubles Com Municating with Telephone Tone Con trol Part 2 e Multitasking and Windows with CP M A Review of MTBASIC e The Computer Corner Issue Number 20 e Designing an 8035 SBC e Using Apple Graphics from CP M Turbo Pascal Controls Apple Graphics e Soldering and Other Strange Tales e Build a S 100 Floppy Disk Controller WD2797 Controller for CP M 68K The Computer Corner Issue Number 21
52. Insert modified code as shown below DELSEND in the BIOS section Other equates as shown in Listing 1 Keep in mind that the values presented here are our own compromise design and not the only possible approach You may desire to modify them for your specific ap plication MDPORT is the port number of our MDISK control port We have chosen to use port 30H If you are using a different port put that port number here CHIPS is the number of 8 chip 256k RAM chip sets that are installed the maximum number is 4 sets giving 1 megabyte total and is used later in MD PARM to calculate the appropriate extent mask EXM and the disk size DSM MDIRSIZ is the maximum number of directory entries allowed We have chosen to allow a maximum of 128 direc tory entries no matter how many chip sets are installed in order to minimize the reserved directory size and maximize the net MDISK storage space Since the MDISK RAM disk is primarily a workspace rather than permanent storage Software version Control port for bank switching Number of chip sets Installed 1 4 each set is 8 256k chips Deleted directory character Zero bank selection MDISK LED ON bit MDISK directory size The Computer Journal issue 30 vs We we ve ve vs Yo wo we we we we Ve Ve we ws we Ve ve vey workspace elbow room seems more im portant than a very large number of potential directory entries MDIRSIZ is used later in
53. Internal Commands e Ampro 186 Networking with SuperDUO e ZSIG Column The Computer Corner Issue Number 26 e Bus Systems Selecting a System Bus e Using the SB180 Real Time Clock e The SCSI Interface Software for the SCSI Adapter e Inside AMPRO Computers NEW DOS The CCP Commands Con tinued e ZSIG Corner e Affordable C Compilers e Concurrent Multitasking A Review of DoubleDOS e The Computer Corner Issue Number 27 e 68000 TinyGiant Hawthorne s Low Cost 16 bit SBC and Operating System e The Art of Source Code Generation Disassembling Z 80 Software Feedback Control System Analysis Using Root Locus Analysis and Feed back Loop Compensation e The C Column A Graphics Primitive Package e The Hitachi HD64180 New Life for 8 bit Systems e ZSIG Corner Command Generators and Aliases e A Tutor Program for Forth Writing a Forth Tutor in Forth e Disk Parameters Modifying The CP M Disk Parameter Block for Foreign Disk Formats The Computer Corner Line The Computer Journal Issue 30 ssue Number 28 Starting Your Own BBS What it takes to run a BBS i Build an A D Converter for the Ampro L B A low cost one chip A D converter o The Hitachi HD64180 Part 2 Setting the wait states amp RAM refresh using the PRT and DMA e Using SCSI for Real Time Control Separating the memory amp I O buses e An Open Letter to STD Bus Manufactur ers Getting an industrial control job done
54. K free memory space even with a full featured ZCPR 3 3 implementation with RAM disk and hard disk support The system may optionally be recon figured to provide 61 25K of free memory for applications The large free memory space is provided by placing the BIOS and ZR DOS modules outside of the normal 64K logical address space and many programs such as dBase II Wordstar 4 0 and Turbo Pascal have been run 44 perfectly under Hyperspace Hyperspace is available including the sample BIOS for 195 and OEM terms are available Contact Echelon Inc 885 North San Antonio Road Los Altos CA 94022 phone 415 948 3820 Programming Interfacing Catalog Group Technology Ltd has announ ced their Fall 1987 catalog of their new and current books and products and it is directed particularly to those who wish to gain or teach hands on experience in in terfacing external devices to microcom puters New hardware items include the DAB 1 Data Acquisition Output Board for the TRS 80 Color Computer which turns the CoCo into an economical controller and data acquisition system which is excellent for learning teaching and implementing real world control applications Some current applications include digitizing and analyzing a torsion beam driving a telescope for automatic selection and tracking of a celestial body controlling the iris of a particle beam accelerator and temperature monitoring and control A new
55. LERR iF SELERR SELERR SELERR Insert this section as a replacement for the driver statement for whichever drive letter you have selected for MDISK Drive F is shown here Note that the label Hard disk here s 7 3 MOISK driver number 050H High nibble Drive F offset from DPBASE 05 3 Low nibble OH 4 3 MDISK type byte OH End of modified Inserted code 2 22 2 sss22222 222Ea e2E2 Q 060H 0 0 Hard disk drive G Hard disk drive P Driver Driver Driver Or iver Driver Oriver Driver Driver Dr iver select error table 0 1 flop 2 E di 3 SCSI 3 not 4 not 5 not 6 not insert modified code as shown below py sk hard disk def ined def ined def ined def ined DEFW MOR VER Driver 7 MISK driver j z333 End of modi fied inserted Code s ssssss222asscssse se2222 PHYEND EQU 2 2222 nsert modified code as shown below s lt s lt s2 lt se222 Entry wee we us we vs wee vs ve MORIVER INC JP DEC JP JP ELMDISK JP MORIVER MDISK driver routines If A FFH then select MDISK OOH then write MDISK OIH then read MDISK A Z SELMO SK A Z MWRITE MREAD SELEND 2 MISK disk read and write routines Go select MDISK Write operation Read operation Nothing else special here we vs vs vs we we us ve Ds ve we ve v x 128 or 4k of directory space This means that we need two 2
56. MDISK 0k RAM supplied including complete manual and software disk only 149 plus 5 shipping and handling California residents add 6 sales tax Checks COD MO accepted 1 wld A i lk TONE ii LARA 21460 Bear Creek Road Los Gatos CA 95030 DUMMY IOP into the DUMMY IOP disk file Also any previously created IOP files such as the ones created with NuKey will most probably crash if you attempt to use them on a BIOS which changed size You will have to use NUKEY COM to create new ones which is a very simple procedure The NuKey IOP Now that you have modified your BIOS to support IOP s you can get on with the task of making your terminal s keyboard a friendly place to work If you are like most computer users you regularly run several keyboard intensive programs such as word processors spreadsheets database managers and even Z System ZCPR3 If your applications are like most applications the keyboard and special function key definitions are different bet ween applications and even when they work you wish they could be the way YOU wanted them You also wish that the definitions would remain the same from program to program Enter NuKey Earlier I mentioned that Joe Wright was a prominent mem ber of the Z System community Joe is much more than that Joe is an experienced Z System Power Programmer When ZC PR3 first came out we were all very impressed Joe Wright s Z System programs are so tightly integrated in
57. MDPARAM to compute the maximum directory size DRM If you want to use MDISK as a battery backed up RAM disk that is used for more per manent storage and you have the need for more than 128 files you might wish to in crease MDIRSIZ In that case you will also have to modify ALO as described below BLKSIZ is the size in bytes of each allocation block Blocks of 2k were chosen as a good compromise Larger blocks waste too much RAM disk space and smailer blocks require more directory space MDSCKS is the directory check scratchpad area size which is used to determine whether the media has been changed We can set this equate to zero as MDISK is a non removable media device hence needs no directory checking MD ALYV is the size of disk storage allocation information scratchpad area ALV This value is equal to the maximum number of data blocks allowed and is computed as DSM 8 1 DSM is the maximum disk size and is computed in MDPARM For simplicity we set this equate to the maximum size needed which is the size required by 4 chip sets or 60 2k blocks MDISK Disk Parameter Information The next MDISK BIOS insert shown in Listing 2 follows the AMPRO label DPBASE which is where the parameters for each drive are listed MDISK looks like a floppy disk to the BIOS so we will operate in the IF NOT HARDS DISK area We re assuming that we re using an all floppy system and using drive F
58. P is a timing diagram or truth table showing the binary states of each selected signal as a function of time There are many other features and LSP is completely compatible with BV Engineering s PCPLOT and PDP for plotting and graphics Contact Peter G Boucher at BV Engineering 2200 Business Way Suite 207 Riverside CA 92501 phone 714 781 0252 Make certain that TCJ follows you to your new address Send both old and new address along with your expiration number that appears on your mailing label to THE COMPUTER JOURNAL 190 Sullivan Crossroad Columbia Falis MT 59912 If you move and don t notify us TCJ is not responsible for copies you miss Please allow six weeks notice Thanks The Computer Journal issue 30 Books of Interest 68000 Assembly Language Programming Second Edition by Leventhal Cramer Published by Osborne McGraw Hill 1986 6 2 x 9 484 pages Hawkins Kane and When learning about a new CPU the first book I buy is Leventhal s assembly language volume because prefer a book which concentrates on the CPU rather than one which spends most of the space on operating system specific interfacing details for some chosen system first I want to learn the CPU after that I ll learn the operating system This book is similar to the Z 80 volume but the design has been improved making it easier to read and there is more discussion and explanation with the programming examples Thi
59. Public Plus and Ampro BIOS 3 8 Messages are handled by Echelon Inc s and Tim Gary s Z Msg Both systems use BYES10 to establish and maintain the remote linkup KMD22 handles the file transfers The hardware and software have undergone substantial evolution over the two and one half years of Lillipute s operation The system went on line for the first time in March 1985 as Z Node 15 one of over 80 Z Nodes around the world dedicated to users of the Z System ZCPR3 ZCPR33 and ZRDOS and CP M It started its life as a single 9 megabyte Kaypro 10 ac cessible at only 300 or 1200 baud An enthusiastic and supportive membership has made it possible to expand to a 144 megabyte two computer 300 1200 2400 baud remote system offering a wide variety of technical advice and public domain software Lillipute Z Node can be reached at 312 649 1730 System 1 or 312 664 1730 System 2 Both systems are accessible by PC Pursuit I encourage TCJ subscribers to call System 1 and System 2 Leave a message to Sysop that s me requesting special TCJ access I will check your name against Art s subscription list If you show up on that list you will be given entry to the public domain software download directories on your next call When you log in for the first time you will be asked for your name and for a password It is best to use your first and last names no middle initial Also make a note of your password for subsequent ca
60. R there is a file pointer that can be moved around using standard control characters or if defined cursor keys In VLU the escape character toggles the cursor between the upper file and lower LBR member fields of file names Many operations can be performed on either set of files Files can be tagged and untagged and two wildcard tagging functions are provided GT group tags all files while W allows a wild card file specification to determine which files get tagged In dividual files or groups of tagged files can be viewed crunched but not squeezed or uncompressed either uncrunched or un squeezed as appropriate The F command will show the size of an individual file or library member at the cursor For library members the size is shown in records as well as kilobytes Ad ditionally tagged individual files can be deleted or renamed and tagged library members can be extracted with or without decom pression The special GB or Group Build function of VLU allows tagged individual files to be built into a new library As I write this article the details of this feature have not been fully worked out but it will be possible for the user to indicate which of the tagged files should be crunched according to an automatic algorithm which will crunch them only if that results in a smaller file and which should be put into the library in their existing form Single individual files will accept the command O to
61. S articles and industrial applications articles If you can get any pocket computer or Z280 articles I ll read them I think a nice project would be a HD64180 replacement for the M100 8085 a drop in the case board with M100 features would be so nice I use software but hardware is my main concern I like articles on the hardware in cluding particular address location of devices if a standard or how to access them if not and any problem areas in in terfacing Please encourage Mr Rose for more S 100 projects How about a SCSI S 100 design I understand that a 1 2Meg 5 o floppy can be controlled via an 8 disk con troller How E A Jay Sage Fan Have a Kaypro 4 84 to which I have ad ded a 20 Mb hard drive Advanced Design Eng and personalized ZCPR3 system My wife and I recently purchased a 6 10 MHz AT compatible clone for use with our Arabian horse breeding business While I am in the process of learning something about MS DOS my first love and greatest interest is in the 8 bit world My interests are those of a hobbyist so please don t forget about those of us out here who fiddle with puters just for fun and personal satisfaction R B PS Tell Jay Sage 1 really appreciate his column An 8 100 User I am a 36 year old Electrical Engineer with an MS and a BS I run the following machines at home Continued on page 46 The Computer Journal issue 30 Lillipute Z Node A Remote Access Sys
62. We can also safely boot normal non MDISK systems since they can t address the extended RAM area where the MDISK directory and files reside When we later re boot our MDISK system the directory and files will still be there as long as the power has remained on Creating Additional Files At Boot Time We can use the same method that we used to create our label file if we wish to also create other useful files at boot time For example if you use PluPerfect s DateStamper utility you can also create the required blank TIME amp DAT file at boot time by adding the appropriate directory data information to MDENTRY and moving it to the second MDISK direc tory location The insert listings in MDISK LBR include a DateStamper equate in the first DELSEND insert that if set to YES will automatically create this file at boot time Log on Message Listing 5 shows the MDISK addition to the AMPRO log on message It is used to notify the operator that the system being booted is an MDISK system Of course you may customize this message if you desire Buffers Listing 6 shows the final BIOS insert It contains MBUF a 128 byte buffer used for MDISK data movement and the values for CSVMD and ALVMD that were set in the first insert Driver Operation The normal driver operating sequen ce is to perform a call or jump in order to pass control to the driver code in the global upper 32k of system memory Then select the
63. addition to the scientific sof tware is SEQS PC Simultaneous Equation Solver for the MS DOS per sonal computers which provides fast ver satile and easy to use capability for solving nonlinear or linear algebraic equations New books on microcomputer inter facing and assembly language program ming supplement older standbys and in clude special emphasis on artificial in telligence expert systems and Forth language Science instructors practicing scien tists microcomputer hobbyists and anyone interested in improving professional affairs will find the catalog a valuable resource The catalog is available at no charge from Group Technology Ltd 6925 Dogwood Road Baltimore MD 21207 2606 phone 301 298 5716 Logic Simulation Program BV Engineering has just released a digital logic simulation program for IBM PC compatibles and the Macintosh com puter After describing a logic circuit and sequence of binary input signals to the program LSP will compute the resulting binary output signals at any or all nodes of the circuit at the specified times LSP contains built in models for com binatorial gates such as AND OR NAND etc sequential devices such as D JK and toggle FLIP FLOPS as well as TRI STATE devices LSP handles all time scheduling and accurately propagates the input and computed output results through the design regardless of the com plexity or nesting of feedback loops The output of LS
64. agazines while they were suppor ting CP M has joined the TCJ crew See his first introductory column in this issue and be sure to respond with the questions and comments we need in order to tailor his column to your needs Being Friendly Ain t Easy In issue 28 Programming Style User Interfacing and Interaction I discussed the need for better user inter facing and this made me aware of how much I have neglected this in my own programs I use the excuse that these are simple programs written for our own in ternal use only and that we know how they work but I ll have to admit that I have problems using programs which I wrote a year ago I keep a folder or notebook for each program with com mented code and notes but there is not enough commenting or notes on the user interface and we shouldn t have to hunt for the notes when we want to use the program GEE GITE IS NOTHING SACRED Now the FULL source code for TURBO Pascal is available for the I8M PC WHAT you are still trying to debug without source code But why Source Code Generators SCG u provide completely commented and labeled ASCII TETAI and UNDERSTOOD aource files which can be edited an SCG s are available for the following products The darndest thing I ever did see Automotive Engineers SAE is working on the development of a standardized automotive communications bus One of the contenders is the Inte Bosch Car Area Net
65. ains more than one record always true on a double density disk it may be necessary to preread the sector to retain valid previously written data in the adjacent records When the record is being written to a newly assigned empty allocation unit there is no data in the adjacent records and no sector preread is required When more than one record fits into a sector it is more efficient to defer the write to disk until the sector is full However when the write is to a directory the write must be com pleted immediately Directory writes always require prereads The BDOS passes the WRITE routine a parameter that helps the BIOS decide if a sector preread is required This write type parameter has the values and meanings e 0 This is a normal write operation This kind of write may require a sector preread and may be deferred e 1 This is a write to a directory record This kind of write may require a sector preread and must never be deferred The Computer Journal Issue 30 e 2 This write is the first write to an allocation unit that has just been assigned to a file Since the allocation unit is empty no sector preread is ever required The write may be deferred How the BIOS uses this information is of vital importance Ignoring this information leads to significant performance degradation using it incorrectly results in lost data and files More will be said about the type 0 and type 2 writes later Fundamental Bloc
66. al Carson of Oklahoma City OK I originally suggested a library shell like ZFILER but working on the contents of a library but Michal pointed out that there is really no need for the visual library utility to be a shell since shell functions like macros performed on poin ted to files will generally not be applicable to library members So he built VLU as a non shell utility that interfaces closely with ZFILER VLU can be invoked in two ways Without any file name specified on the command line it tries to open a library whose name is the same as the file name stored in the Z3ENV system file 2 This system file is where ZFILER keeps the name of the file it is currently pointing to If one has a ZFILER macro called for example V with the simple script VLU invoking this macro The Computer Journal Issue 30 while pointing to a library or to another file with the same name as an LBR file in that directory the library will be opened for work by VLU Alternatively one can specify the name of the file on the command line in which case this name takes precedence over any name in system file2 Once VLU is running the display contains two fields The upper field is like that in ZFILER It displays the names of the files in the currently logged directory The lower field is similar in appearance but shows the names of the member files in an open library file If no library file is currently open this field is blank As in ZFILE
67. al time data recording work space for graphics routines or for many other applications Wouldn t it be nice for example to have your whole operating system buried on MDISK giving you a TPA of 63k or more The RAM disk sof tware is the only application that has been developed at this time as it is an ap plication that is useful to almost everyone but the extended RAM hardware needs only the additional control software to provide these other potentially powerful features In the meantime enjoy using the new speed of your Little Board MDISK RAM disk workspace The MDISK user disk with the source files for the insert listings plus some utilities is available on an AMPRO DSDD format 5 25 disk for 10 postpaid in the U S amp Canada The Computer Journal Issue 30 Non Preemptive Multitasking by Joe Bartel Hawthorne Technology Multitasking where one computer appears to be executing more than one program at the same time is needed in many con trol applications Usually a terminal or some kind of keyboard and display is communicating with the operator while a process is being monitored and or controlled in the background This is dif ferent from common programs being written for a PC where only one thing is happening at a time and one job is finished before the next job starts For every problem there is usually a simple solution and a complex solution There are many multiuser multitasking operating systems on th
68. ally designed custom programs will operate under these conditions but that s why we program right I like CP M and the Z80 but I am facing the problem of the 64K memory limitation While the HD64180 is an im provement I think that I ll have to go to Hawthorne s 68000 system with its large continuously addressable RAM and position independent programs in order to satisfy myself In the meantime I m bashing CP M in order to develop my skills and decide what I want in a system A lot of my CP M development work is being moved to my Morrow S 100 Z80 systems which provide 24 bit extended addressing and additional 64K banks of RAM I just have to dig into the manuals and figure out how to use the banks for programs and systems Even though much of what I do will be rather strange and not fully applicable to other systems I ll publish some of it in order to give you something to think about If you want to hear more about it you ll have to let me know by responding with your comments and telling us what you are doing Z30 or 8080 Digital Research made the smart move of supplying their ASM assembler with their CP M operating system but it was written for the 8080 CPU which was in use then and now we are almost all using systems with the much better Z80 CPU but too many people are still using their old ASM 8080 assembler because it came with the system We re doing our eight bit systems a disservice by contin
69. ange CPU cards while leaving all the rest of the cards intact Now I know that some of the timing parameters were changed but we will leave that for my friend to write about in detail We had a number of discussions on FORTH in the STD bus environment and hopefully will get a few articles about that These people felt they couldn t do it with any other language and if we pester them maybe we will get some articles giving us the insight into why it works so well Overall the SOG was not a high point of my trip I enjoyed seeing the staff again and talking with friends the high point was no masters work The HTPL group has promised me some new items and so I got excited again about bringing up the HTPL on my S 100 system We talked about having our own meeting next year if the SOG doesn t happen dorms maybe unavailable but Dave is looking for alter natives somewhere around Portland and mostly aimed at the 68K user if enough of you write we may have one before the SOG There was considerable talk and I agree that TCJ could become the Z80 STD bus and 68K users magazine For me personally my future is cloudy and un certain I have been trained to help people with the PC line of products but I hate them I had even more reason to dislike them after stopping at a friend s place on the way home He has been helping a local co op health clinic sort out their computer problems They purchased a turn key computer syste
70. at connect disconnect stuff that Modula2 uses The parser would check the types and compile appropriate code just as it does for any statement A file is created by preceding any variable declaration or procedure declaration with the word FILE for example FILE REAL namel 0 FILE PROC name2 REAL x y INT j eceee The file namel is an array of real numbers that starts out with 0 length while name2 becomes a compiled program stored on disk To execute it type name2 param param param The parentheses are optional to make it more like typing a con ventional command line Nothing like ARGC or ARGV will be needed In C terminology FILE is a class along with STATIC AUTO etc The syntax of my language shown in Figure 1 is a The Computer Journal Issue 30 Figure 1 HL32 syntax Any statement can be assembly or high level Free form source any number of statements can appear on a line Keywords are ali caps because of large number of mnemonics User defined identifiers must start with a lower case letter User defined identifiers arbitrary length al characters significant Both assignment ana equality comparison use sign No punctuation is used between statements or after labels Variabie definitions resemble those of C except no commas or semicolons used Conditional compilation like that of C Operator precedence like that of BASIC Complex numbers a built in data type with comp ex transcendentals
71. bes a single sided single density drive with a block size of 2k and a sector size of 128 bytes MDRIVER is the address for our MDISK driver number 7 which is shown in Listing 3 Whenever the MDISK drive is selected the BIOS directs us to driver 7 for further processing MDISK Drivers The MDISK read and write routines MREAD and MWRITE are very Straightforward and function in similar ways They begin by setting a one level local stack to make sure that the stack pointer will not get lost PAGESEL tran slates the track and sector numbers to the bank number our hardware needs and turns on the MDISK drive LED The data is then moved in 128 byte blocks using the OUT MDPORT instruction to select the desired bank and the Z80 LDIR instruc The Computer Journal Issue 30 tion to move the data between the selected locations When we are finished we restore the stack and select the CP M bank ZBANK which also turns off the MDISK drive LED on our way baek to the calling routine MDISK Setup Routines When the system is cold booted or reset we need to initialize the MDISK directory area so that we can use it We also don t want to lose our MDISK direc tory if one is already present so we need to provide a routin that tests for the presence of an MDISK directory and will create one if it doesn t already exist We insert this routine shown in Listing 4 in to the BIOS following the BIOS label NOT7 just after the sign on
72. ble from the caller Better safe than sorry e Step 2 Wait for any disk operation in progress to com plete If a read is needed the read routine will be building a flop py disk controller command string In the case of a retry the string may be executed up to 15 times Even as we speak a retry may be in progress It is just too risky to continue until all previous operations are complete Step 3 Check for the drive door closed and a disk inserted This must be postponed until after step 2 because a command string must be sent to the floppy disk controller There must be a disk in the drive because the read routine needs to know if the read is single or double density If the disk in the drive is single density f The Computer Journal issue 30 Big news for the brave few of you who started this whole thing WORD STAR CP M Edition Release 4 Finally all the if only s Over 100 truly useful improvements including undo macros on screen boldface and underline and multiple ruler lines stored with documents Even something to help you get the most from your laser printer Everything you need to be at the forefront of technology Again System requirements CP M 80 2 1 or higher 54K TPA w Math 51K TPA without Math Disk requirements two 5 1 4 DD drives or two 8 drives or one DD floppy drive and a hard disk i i ns a a a a eee e a To order WordStar CP M Edition Release 4 fill in this coupon a
73. ch is taking input for a program from something other than the keyboard these are also discussed in Lacobie s article These features are available with PC MS DOS but there is no reason why we can t implement them under CP M One of the things which I like about the CP M systems that I am using is that the operating system is entirely on disk some systems have part of the O S in ROM Another feature is that I have the BIOS source code With the O S entirely disk based I can use a number of custom modifications for different applications and the BIOS is easy to modify because I have the source code The CCP and BDOS sections are a little more intimidating but after studying the output from C C Software s CP M 2 2 Source Code Generator and reviewing Hilton s New Dos series I feel ready to tackle the entire operating system if you are serious about the CP M O S you must get C C s SCG for CP M 2 2 I m not going to write a huge do everything system and I don t intend to replace ZCPR3 3 which Pll continue to use for normal operations what I plan is a series of special O Ss for non conventional uses For these special ap plications Ill strip out every part of the CCP BIOS and BDOS which isn t being used and add any features which I want for that application The reason I ll strip the O S is to save space and speed the operation For an ex treme example a data gathering station may not even hav
74. cification explained later can tell JetFind whether or not to ignore case If other characters are allowed in labels they could be listed inside the brackets as well There is not enough space here to give a complete description of JetFind s regular expression syntax Suffice it to say that it can perform just about any search you would ever want to do A second major feature of JetFind is that it is not limited to searching single files you can specify whole collections of files to search You can give a list of ambiguous file specifications both for files to include in the search and files to exclude from the sear ch These files can all come from a single directory or files from many directories can be included For example the file list TEXT D C TEXT A indicates all files in the named directory TEXT yes JetFind is fully ZCPR3 compatible with a file type of D C but not that is The Computer Journal issue 30 the meaning of the prefix files whose name begins with A Note the in the file type The intention here is to search all DOC files By including the for the middle letter files of type DQC squeezed DOC files and DZC crunched DOC files will be included as well JetFind automatically uncompresses both squeezed and crunched files as it Searches Moreover JetFind is not limited to searching individual files It can even search through members of libraries If the first file name in the
75. cribers by Richard Jacobson cccccccccceceneaneneneeeecesene 41 Columns Editorial oi ne eaea E a eee esas lates 3 Readers Feedback sosssesessesrsssrerserseess 5 ZCPR3 Corner by Jay Sage cccccceeeeceeeeeeereees 20 CPIM Corner by Bob Blum 00 cceccccce cece eee et teens 29 INOW aso Sindee se iene Soe eee EE T E donee 44 Books of Interest cccccceeceeeeeeeeeeeeesaeee 45 Computer Corner by Bill Kibler ccccceesee ences 48 D Who we are Echelon is a unique company oriented exclusively toward your CP M compatible computer Echelon offers top quality sottware at extremely iow prices customers are overwhelmed at the amount of software they recieve when buying our products For examole the Z Com product comes with approximately 92 utility programs and our TERM Iii communications package runs to a full megabyte of files This is real value for your software dollar ZCPR 3 3 Echelon is famous for our operating systems products ZCPA3 our CP M enhancement was written by a software professional who wanted to add features normaily found in minicomputer and mainframe operating systems to his home computer He succeeded wonderfully and ZCPR3 has become the environment of choice for power CP M compatible users Add the fine tuning and enhancements of the now available ZCPR 3 3 to the original ZCPR 3 0 and the result is truly flexible modern software technology
76. cture I understand that there is a second volume out with information on additional programs Computer Numerical Control byJoseph Pusztai amp Michael Save Published by Reston Div of P H ISBN 0 8359 0924 7 This book is apparently intended for those involved with numeric machining and includes a lot of information on milling drilling turning calculating cut ter centerline distances etc The infor mation looks complete and this will be part of my permanent library Engineering Foundations of Robotics by Francis N Nagy amp Andras Siegler Published by Prentice Hall International ISBN 0 13 278805 5 A high level book with an overview of robotics stressing the underlying mathematical techniques and principles relating to the kinematic models of robot manipulators Definitely not hobby level it includes topics such as Description of a Wedge by Transformation Matrices Transformations Along the Kinematic Chain Gripper Positioning by Euler Angles for Roll Yaw Roll Geometry and Servo Systems for Robot Control There is a lot which I don t understand but this book is on my required reading list Multiple Processor Systems for Real Time Applications by Burt H Liebowitz amp John H Carson Published by Prentice Hall ISBN 0 13 605114 6 The purpose of this book is clearly stated in the preface which says in part This book presents a pragmatic ap proach to the design and construction of a class of computi
77. d disk code Between this statement and the Cold Boot code add the following code New Code This is the Auxiliary Jump Table for the extended IOP meee wee CONST CONIN CONOUT LIST PUNCH READER LISTST 3333333 Be sure you place this code before the label BOOT because all code after BOOT is overlayed by system storage after a Cold Boot We need to have IOPRET resident all the time The next set of changes are to the ZBOOT routine Otd Code ZBOOT LXI B 3 Set up the ZCPR3 command tine LXI H CMOSET pointers Lx 0 23CL Ow LOIRBO LXI 8 10 Move the automatic command to LXI H AUTOCMD a the ZCPR3 command line LXI 0 Z3CL 3 Ow LDIRBO LXI B 11 Move the initial path descriptor LXi H PATH to the proper location LXI D EXPATH Dw LDIRBO A MYI A OFFH STA Z3WHL Turn the wheel byte on LXI H ENV Move the environment to LXI D Z3ENY the proper location LXI B ENVEND ENV Ow LDIR8O ENDIF ZOPR3 init XRA A STA COISK Indicate disk 0 selected STA HSTACT STA UNACNT STA HSTSIO GOCPM Set host buffer inactive Clear unalioc count Assume side zero rr ret JMP initialize amp jump to CP M LOGMSG 08 CR LF LF New Code ZBOOT LXI 8 3 3 Set up the ZCPR3 command line XI H CMDSET 3 pointers LXI 0 Z3CL ow LDIRBO A ux B 10 3 Move the automatic command to LXI H AUTOCMD the ZCPR3 command IIne LXI 0 Z3CL 3 Dw LDIR80 3 LXI 8 11 Move the Initial path descriptor LXI H PATH
78. d egg barrier but that s not the whole story because there must be a reason to do it Here are some of my reasons for wanting to use the 32000 1 The set of generalized 32 bit registers and floating point registers the 2 general operand instruction set and the un fragmented addresses make programming very easy and allows almost any software to epitomize the KISS principal For example the statement MULL varl var2 does a double precision floating point multiply of var by var2 If the operands are in memory then no registers are used The statement MOVST U moves a string while translating characters and checking for a specified ending delimiter 2 If I ever do some computing instead of building my com puters my primary interest is in scientific computations My 32000 transcendental routines do the Savage in 3 02 sec with an error of 1 6e 9 Because of the compactness of the code it s no bother at all to make complex numbers a built in data type and to include complex transcendentals 3 The linear address space allows all software development tools to be integrated into the operating system in a coherent way allowing much more efficiency on the human side of development activities lt also allows in memory editors large arrays etc When I first happened onto a windfall 32016 board I only wanted to do some math and I wrote a FORTH 83 system to ser ve as a driver I originally wrote the Forth system because I thou
79. d is the responsibility of the BIOS In general any write may be postponed until a more con venient time for instance when the write buffer is full However special directory writes occur which can never be postponed On ce the foreground write operation is invoked the BIOS returns to the calling program to allow maximum concurrency The write algorithm is as follows Step 1 Switch to a local stack There is no way of knowing how much stack space is available from the caller Better safe than sorry Step 2 Wait for any disk operation in progress to com plete If a write is needed the write routine will be building a floppy disk controller command string The previous disk com mand string may still be executing e Step 3 Check for the drive door closed and a disk inserted This must be postponed until after step 2 because a program string must be sent to the floppy disk controller There must be a disk in the drive because the write routine needs to know if the write is single or double density If the disk in the drive is single density 10 e Step 4 Transfer the data to the 128 byte holding buffer e Step 5 Construct the floppy disk controller command string set the write flag then start the foreground write Note the foreground clears the write flag when the write is complete Step 6 Restore the stack and exit to the calling program No need to wait for the operation to complete the foreground program wi
80. d to load the system onto track 0 only Fortunately both programs were small Bibliography The following books and publications have proven to be of exceptional value in providing information about CP M or about a floppy disk controller that is particularly good at concurrent processing the NEC 765 Cortesi David E Inside CP M A Guide for Users and Programmers Holt Rinehart and Winston New York 1982 CP M 2 Alteration Guide Digital Research Pacific Grove California 1979 Hogan Thom Osborn CP M Users OSBORN McGraw Hill Berkeley California 1981 Murtha Stephen M and Mitchell Waite CP M Primer Howard W Sams amp Co Inc Indianapolis Indiana 1980 SA800 Series Diskette Storage Drive Double Density Design Guide Shugart Associates Sunnyvale California 1977 Weiner Richard and Gregory York A Single Double Den sity Floppy Disk Controller Using the PD765 NEC Microcom puters Inc Wellesley Masschusetts 1980 Guide The Computer Journal Issue 30 Implementing ZCPR3 IOP Support for Ampro Featuring NuKey a Keyboard Re definition IOP by Rick Swenton If you are the proud owner of an Ampro Z80 Little Board you are fortunate to have one of the finest complements of har dware and software available for a very modest price Like any well designed piece of hardware performance is dependent on well designed software Ampro in its infinite wisdom chose to implement support for Richard Co
81. d trom page 5 We share his view of what is needed that is to say a Z System running 64180 based card or cards for industrial control Our company has we think done that and more We have built a two card set for the STE IEEE P1000 standard bus The base card has CPU math processor Real Time Clock and bus interface The second card has M or IM DRAM FDC SCSI and Centronics i f The main card is designed for use as a lower cost delivery vehicle for installation in applications The two card set has a mode in which it will run all SB180 sof tware including stuff which does direct I O not even via the BIOS The only non SB180 compatible things are the Cen tronics i f and lack of 8 disk support The only way in which we have failed Mr Nelson is that we are using the wrong bus The STE bus is an asynchronous bus using two part connectors and with a number of advantages over STD However there are more STD users out side England than STE users We have long considered an STD ver sion of our system the changeover would not be too difficult as STD cards are larger and the STD bus simpler than STE Does anyone else out there want to encourage us to do so We would be in terested to hear from potential users or distributors In addition to Z Systems our cards also run a control BASIC with programs ROMable so non Z System people at least have an alternative David G Collier MA J B Designs amp Technology Ltd
82. de Print Rename Save Undo exit Entering C will clear the script editing area E will enter full i screen editing mode F will reformat the script converting it te upper case and placing each command on its own line even if the user entered lines containing multiple commands separated by semicolons The I command is similar except that it indents th 23 ro lines by three extra spaces for each level of IF nesting Thus a script might appear as follows IF EQ I OR NU 1 ECHO SYNTAX IS ELSE IF NU 2 COMMAND FOR ONE FILE SPEC ELSE COMMAND FOR TWO FILE SPECS 1 FI This format makes it very easy to see the relationship between the flow tests and to detect missing FIs Entry of complex conditional aliases is greatly facilitated by the use of the tab key to indent the script as it is entered The I command will reindent the display according to the actual flow levels even if the user made a mistake The spaces tabs used to format the display are not part of the actual alias script However leading spaces entered by the user to invoke extended command processor operation for example will be included in the script and are displayed in addition to those added by the indenter The F command will show the real contents of the script automatically deleting the indentation tabs The L oad command tells SALIAS to clear any existing script and to load an alias file for editing I
83. e the term record when referring to 128 byte data blocks that programs read and write The term sector is reserved to refer to the smallest data unit written or read on a disk CP M uses the name allocation unit to describe the minimum incremental chunk of space allocated to a file A single density exchange format disk is divided into 243 allocation units of 1K each Two allocation units are reserved for the directory The space remaining can be divided into one 241K file or 241 files of 1K if the directory could hold 241 entries The double density system designed here changes the allocation unit size to 4K and the number of allocation units to 171 4K x 171 684K The CP M disk is organized so the operating system starts on track 0 and continues for as much space as required On a single density system two full tracks 8K are normally required to hold the operating system On a double density system one track holds 9 sectors of 1K The operating system growth due to the change to double density does not force the use of a second system track because 2K of the 10K space is uninitialized disk buffer See Table 1 for a summary of data units relevant to the current discussion and Table 2 for a summary of disk drive characteristics The directory immediately follows the system track s Its size changed but the minimum space is one allocation unit All space after the directory is allocated to file storage Each directory entry is 32 bytes
84. e 508 task2 4 4 tsk2r 512 alloacte 512 tsk3o 512 allocate 508 task3 4 4 tsk3r tskip tskpn 1 Itskid tskOp tskpn swaptsk start system return end proc next tskpn tskOp swaptsk save old task tskid dup tskid if 3 gt then 1 tskid tskOp tskpn end tskpn 8 tskpn tskOp tskpn swaptsk end start new task user interface proc task repeat repeat next chkchr until upcase case LAY B LC end false until end action for command A here action for command B here action for command C here we timed sequence task proc task2 while true do next gettime now get current time if now target gt then doaction do timed action target interva l Itarget end set new time target end end generalized task proc task3 any repeating loop goes here end SWAPTSK is used by next to change tasks The first part of the system is PROGRAM where the HTPL program will start executing There needs to be a startup routine that gets each task ready to run It will only execute once when the program starts Its purpose is to initialize the tasks the tables used to switch tasks and start the first task Because HTPL uses two stacks space for the stacks must be allocated The main program allocates space for the parameter stack for each task Next the return stack space is allocated The starting address for the task is plac
85. e IOP support in their BIOS But then the Ampro had been out in the market before the SB 180 In this article I will show you how to modify the Ampro BIOS to support IOP s I will also provide an overview of Echelon s NuKey IOP which is an advanced function key re definition program that allows you to redefine your function and cursor keys on the CRT terminal Changing the BIOS I am using Ampro s BIOS version 3 8 but the changes are fairly generic and also apply to the earlier versions although you may have problems finding some of the locations in the older ver sions Of course to make the changes you will need a copy of the BIOS source code BIOS38 ASM or whatever version you have The BIOS source code is available from AMPRO In the current Ampro ZCPR3 implementation the following areas are initialized by the BIOS addresses are in Hex earlier BIOS versions did not implement all of these FFDO ZCPR3 External Stack FFOO Muitipte Command Line Buffer FEOO Environment Descriptor FDDO ZCPR3 External FCB The Computer Journal Issue 30 FD80 ZCPR3 Message Buffers FDOO Shel Stack FCOO Named Directory Area FAQO Flow Control Package F200 Resident Command Package We will tocate our IOP segment 1 5k below the RCP ECOO Input Output Package So the first change to make is to define the address of the IOP Find the IOP and IOPS equates and change their values as follows ld Code 10P EQU 00000H
86. e Part One e Telecomputing with the Apple II Beginner s Column Getting Started e Build an Epram Nu r2 e File Transfer Programs for CP M e RS 232 Interface Part Two Build Hardware Print Spooler Part 1 Review of Floppy Disk Formats e Sending Morse Code with an Apple II Beginner s Column Basic Concepts and Formulas Issue Number 3 e Add an 8087 Math Chip to Your Dual Processor Board e Build an A D Converter for the Apple II e Modems for Micros e The CP M Operating System Build Hardware Print Spooler Part 2 Issue Number 4 e Optronics Part 1 Detecting Generating and Using Light in Elec tronics e Multi User An Introduction e Making the CP M User Function More Useful e Build Hardware Print Spooler Part 3 e Beginner s Column Power Supply Design Issue Number 8 e Build VIC 20 EPROM Programmer e Multi User CP Net e Build High Resolution S 100 Graphics Board Part 3 e System Integration Part 3 CP M 3 0 e Linear Optimization with Micros Issue Number 14 Hardware Tricks Controlling the Hayes Micromodem II from Assembly Language Part 1 S 1008 to 16 Bit RAM Conversion Time Frequency Domain Analysis BASE Part Two e Interfacing Tips and Troubles Inter facing the Sinclair Computers Part 2 Issue Number 15 e Interfacing the 6522 to the Apple II Interfacing Tips amp Troubles Building a Poor Man s Logic Analyzer e Controlling the Hayes Micromodem
87. e Step 4 Find out if the record is already resident in the write buffer or the read buffer Skip to step 7 if the record is already present Step 5 Build the floppy disk controller command string set the read flag then start the foreground read e Step 6 Wait for the foreground to finish Note the foreground clears the read flag when the read is complete Step 7 Transfer the record to the calling program Step 8 If the requested record is the last record in the read buffer then construct the floppy disk controller command string and start the predictive read ahead to refill the read buffer e Step 9 Restore the stack and return to the caller The floppy disk controller command string depends upon the sector and track the kind of operation and the kind of floppy disk controller you have The string must always be built before the flags are set just in case an interrupt door closed for example happens But the command string must be built after all previous disk operations are complete lest the command in progress be overwritten The Write Algorithm The write request is complicated by the need for prereading a sector when the write is into a preexisting file The BDOS sim plifies this task by informing the BIOS when a write is to an empty allocation unit A sector preread is not required on sequential writes to a previously unallocated unit After the first write keeping track of whether or not a preread may be require
88. e an attached console or disk drive and the O S may be ROM ed In this case it might be easier to start from scratch rather than modifying CP M but there are other in between cases where it will be easier to start with an existing system I call this BIOS Bashing My dictionary defines bash as 7 to strike with a crushing or smashing blow 2 a crushing blow 3 a lively party a wildly good time The definition you choose may depend on the outcome but I consider BIOS Bashing to be the heart of com puting because that s where the real ac tion starts The stripped down O S will free up RAM space for features such as pipes redirection and installable device drivers something else I m stealing from PC MS DOS Where I need special O S features which can be called from a program which runs under conventional CP M or ZCPR3 3 I m even thinking about reading in the special O S block moving it up into the top of high memory running the special section and then using a short bootstrap loader to reload the regular system In this case I may have to write any passed parameters out to a tem porary disk file and read them back in This may sound nuts but why have all that RAM taken up by unused portions of the O S while running special applications which could make good use of the ad ditional RAM We overwrite the CCP while we are not using it why not over write the BIOS and BDOS while we are not using them Only speci
89. e contains 8 entries The Computer Journal Issue 30 Table 2 Orive Characteristics Single Density Record Size Bytes Tracks Sectors Per Track Records Per Sector Records Per Track Record Capacity 128 Bytes Drive Capacity KI lobyte Tracks Reserved for CPM Fite and Directory Capacity Allocation Unit Size Bytes Atlocation Unit Size Records Allocation Units Tracks for Directory and Files Directory Allocation Units Directory Records Olrectory Entries 32 Bytes Directory Capacity Double Density 128 128 77 26 1 26 2002 250 25K 2 243K 1024 8 243 75 2 16 64 2K File Storage Capacity 241K For a double sided disk all the per track and per disk figures are doubled Foreground Tasks All the foreground tasks are interrupt driven The necessary command strings are constructed in background the appropriate flags are set and the background task generates an interrupt by forcing the floppy disk controller to seek to the required track It is of vital importance that the above items be done in this order Chaos would result if the flags were set and an interrupt occurred for some external reason before the command string was built The specific interrupts that cause a switch to foreground processing are Disk drive door being opened the drive becomes not ready e Disk drive door being closed the drive becomes ready Previous read or write has been completed e Previou
90. e market today of which Unix is just one example There are also many small real time kernels available on the market that implement preemptive multitasking without file management If only some of the features of a full multitasking system are needed then a special purpose program can do the job without many of the costs and problems that occur with a full generalized solution By having a model of a nonpreemptive multitask system to follow it is easier to conceptualize a solution and plan a program for a specific application How Preemptive Multitasking Works In a normal or preemptive multitask system there is a scheduler module that takes over and takes control of the system away from one task and gives it to another task The task swap can be in response to an interrupt from an external device or the result of a condition set by another task The most common event is requesting I O which causes the task to wait until the request is filled A task may also be swapped because the time allotted to it has expired and it is time for the next task to run awhile Programs start to get complicated when a task can be in terrupted at any point instead of running to completion First any shared routines have to be reentrant That means it must be possible for a second task to start executing the routine before the first task has finished its execution of the routine Any data areas that are shared by two or more tasks must have locks and semaphores
91. e text string or a regular expression a UNIX concept Let s take a simple case first Suppose you want to find all lines that contain either Smith or Jones In interactive mode you would enter the patterns one at a time in response to the prompt Just hitting carriage return would end pattern input In command mode you would enter for the search pattern the following ex pression SMITH JONES The special character represents or From command mode of course one cannot distinguish upper and lower case To do that you must use interactive mode Now let s consider a more complex search that would make use of a regular expression Suppose we want to find all labels in an assembly language program We could use the following regular expression A Z A Z0 9 The first term in brackets means a character from the set of letters ranging from A to Z The second term in brackets is the set in cluding the digits from 0 to 9 also i e an alphanumeric character The asterisk means that the previous character specification may occur any number of times including zero times a would require at least one occurrence Finally the colon on the end represents the character If labels have to be at the left margin we could use the regular expression A Z A Z0 9 A caret at the beginning of an expression indicates the beginning of a line A mode control spe
92. e to get down on paper before this article has to be sent in Echelon and I I practically fainted when I saw the byline on my last column and I wonder if both Echelon and my real employer did too The byline read Jay Sage Echelon Inc I guess Art Carlson misin terpreted my statement that I had joined the Echelon team In no way am I an employee or official representative of Echelon In real life I am still a physicist at MIT doing research on special analog devices and circuits for image processing and neural like computing Digital computing is still essentially a hobby The members of The Echelon Team are independent programmers who cooperate with Echelon and each other to ad vance 8 bit CP M compatible computing Other members of that team to mention only a few are Bridger Mitchell author of DateStamper BackGrounder and JetFind Joe Wright author of the auto install Z System and the BIOSs of most of the recent popular 8 bit computers Ampro SB 180 On and Al Hawley sysop of Z Node 2 the only one to sign up for a node before I did and author of the REVAS disassembler and the new ZAS Supporting 8 Bit Software Developers Though team members have no personal stake in Echelon as employees or owners they do benefit to some extent from royalty payments for their software that is sold Nevertheless before tur ning to the technical material for this issue I would like to make an unabashed plea to all of you
93. e will be zero The first should be set to OECOOH as shown below Old Cade IF ZOR RESERYE EQU OFDOOH 3 OFDOOH If ZCPR3 ENOIF iF NOT ZCPR3 RESERVE EQU 00000H 3 OOOO0OH If no ZCPR3 ENO IF New Code IF ZCPRS RESERVE EQU OECOOH 3 OECOOH If ZCPRS ENDIF IF NOT ZOR RESERYE EQU 00000H 3 00000H if no ZCPR3 ENDIF That completes the BIOS changes You can assemble the BIOS source and check for errors IOP Theory The original concept of an IOP was to remove ail console printer reader and punch device drivers from the BIOS and place them in the IOP In this way separate IOP s could be created for special applications which would otherwise require modifications to the BIOS For example you could have an IOP which has data sent to the console port and the modem port at the same time so that two users could be attached to the computer You could make changes to your BIOS to do this but I am sure you would not want these two devices in parallel all the time You would then need two separate BIOS s on two separate boot disks However with the IOP approach the console and modem drivers are in the IOP You could create a standard IOP and a custom IOP with the console and modem in parallel Each could be loaded on demand thereby transforming standard I O to a custom one and back again A side benefit is the decrease in size of the BIOS after the The Computer Journal Issue 30 device drivers are removed You do lose the
94. ed at the top of the return stack that has been allocated To start the process going the program calls SWAP TSK with a pointer to TSKOP where its own parameter stack pointer and its return pointer will be saved The other pointer is to where it will find the parameter stack pointer and return stack 38 pointer for the first task When the return statement is executed then the first task starts The second part of the system is the routine that transfers control from one task to the next task This routine which we call simply NEXT looks like an ordinary procedure call to the task giving up control The difference is that it doesn t use any arguments and it doesn t return any results The NEXT routine uses SWAPTSK twice once to get into the scheduler and once to get out of it If the task stack is used for the scheduler routine then it would be possible to rewrite this to use SWAPTSK only once If there are routines that use variables and are used by more than one task then the values of the variables should also be swapped It is important to realize that this is a generic prototype routine that needs to be customized for the specific set of tasks for which it will be used The final and smallest part is SWAPTSK swap task a routine that needs to be added to the runtime library HTPLRTL or linked in as an include file The SWAPTSK is in assembler because it is much easier to do that way The first job of the SWAPTSK routine is to save
95. ent system like that in Turbo Pascal When ZAS encounters errors in assembly it stores enough information about the first error in the environment that an editor can automatically locate the line with the error Thus one can make an alias that bounces between the assembler and the editor in very convenient fashion As an added bonus the Echelon version of ZAS includes as the one from Mitek always did the option to generate in line assembly code for Turbo Pascal If you have an older version of ZAS ZLINK you should definitely order the upgrade priced at just 20 for the software alone or 30 with an updated manual If for some reason you do not want to do that you should at least destroy any copies of the older versions that you have lying around New ZCOM Now I would like to move forward in time and talk about a product that is in the works though with the delay between when I write these columns and when they reach readers it may be on sale by the time you read this This product is New ZCOM or NZCOM Joe Wright s utterly spectacular follow on to ZCOM This product will make manually installed Z Systems obsolete because manually installed systems will now offer less performan ce than NZCOM systems The Computer Journal Issue 30 SAGE MICROSYSTEMS EAST Selling amp Supporting The Best in 8 Bit Software e Plu Perfect Systems Backgrounder II switch between two or three running tasks under CP M 75 DateStamper
96. er KX Exit from SALIAS after saving the file KN Assign a new name to the script KQ Quit without saving the script KR Read in another alias script and append it to the commands currently in the edit buffer This is very convenient for combining scripts from multiple aliases KF Reformat the alias listing each command on its own line removing any flow control indentation and converting to upper case 24 KL Indent the alias display to show flow control nesting KU Undo changes that have been made to the script KP Print the script KM Toggle the mode of the alias between normal and recursive The editing commands follow the familiar WordStar pattern Even QS move to beginning of line QD move to end of line and QY delete to end of line are recognized The special form QZ will zap clear the entire script so you can start over R and C move to the first and last lines of the script respec tively QF allows searching for strings and QA allows search and replace L will repeat the last search or search and replace V toggles between insert and overtype modes SALIAS is available in two versions The longer version has imbedded help information that can be called up using J In the shorter version the help information has been omitted and J instead is used to toggle the cursor between the beginning and the end of the current line I should mention a few other featu
97. er 90 00 1 disk 24 Speciali hems 20 through 23 169 00 4 disks 25 DSD 80 Ful Screen 129 95 1 disk 27 The Libranes SYSLIB Z3L18 99 00 8 disks and VLIB 28 Graphics and Windows Libranes 49 00 1 disk 29 Special hems 27 28 and 82 149 00 9 disks 30 ZBO Turbo Modula 2 Language 89 95 1 disk System 40 Input Output Recorder 1OP VOR 39 95 1 disk 41 Background Printer IOP BPrinter 39 95 1 disk 44 NuKey Key Redetiner IOP 39 95 1 disk 45 hems 40 through 44 89 95 3 disks 60 DISCAT Disk cataloging system 39 99 1 disk 61 TERM3 Communications 99 00 6 disks 64 2 Msg Message Handling System 99 00 1 disk lity 49 95 1 disk 81 ZCPR3 The Manual bound 350 pages 19 95 82 ZCPR3 The Libraries 310 pages 29 95 83 Z NEWS Newsietier 1 yr subscnpton 24 00 84 ZCPR3 and OPs 50 pages 9 95 85 ZADOS Programmer s Manual 35 pages 8 95 88 Z System User s Guide 80 page tutorial 14 95 includes ZCPR3 The Manual i ORDER FORM ITEM PRICE Echelon Ine Payment to be made by 885 N San Antonio Road Los Altos CA 94022 USA eea i 415 948 3820 order line and tech support O Money Order Telex 4931646 O UPSCOD NAME O Mastercard Visa Subtota ADDRESS AET Sales Tax California residents add 7 sales tax Shipping Handling TELEPHONE DISK FORMAT Add 4 00 shipping handling in North J REQUESTING CATALOG America actual cost elsewhere Total The Computer Journal issue 30 Editor s Page Ind
98. es The automotive industry is going for electronics in a big way and the Society of current help wanted ads are Com munications Networking Database Management Factory Automation Motion Control Interfacing With Com munications Real Time Control of Fac tory Workstations Emmbedded Processors Real Time Distributed Con trol Network Using Digital Closed Loop Control Techniques Signal Filtering Prior Experience with 8051 Microprocessors Real Time O S Design and Implementation Compiler Design Microprocessor Based Industrial and Vehicular Instrumentation Controls ASSEMBLY Language Programming Several people have tola me that they can t fill their job openings for people who can program in assembly language for real time embedded controllers but that there are lots of graduates who know about spreadsheets the IBM PC and a High Level Language they have no job openings for these people An RBBS for TCJ Subscribers After I announced the end of the TCJ BBS because of the problems with our long rural phone line Richard Jacobson offered to open an area of his Remote Ac cess System Z Node 15 to TCJ sub scribers His description of the system is in this issue and we will be monitoring your use and messages to decide what files need to be placed in the TCJ section A New CP M Author Well really not new to CP M users but rather new to TCJ Bob Blum who formerly edited a CP M column for two other m
99. es in this article entirely in Z80 code for clarity The com plete insert listings in 8080 code are available as MDISK LBR on the TCJ disk If you have the BIOS source code 30 disk handy you might want to bring it up on your word processor at this point and follow along MSIZE One result of adding additional code to the BIOS is that it slightly increases the size of the BIOS In order to compensate we must reduce the size of the TPA by decreasing the value of the BIOS equate MSIZE by one This amounts to a decrease of 1k in TPA size For example if you are presently using an all floppy 60k BIOS you would need to change MSIZE from 60 to 59 when you add the MDISK drivers giving you a 59k MDISK system You will also need to use ZMOV CPM to generate a new operating system of the new size for use with your new BIOS The Basic MDISK Equates The MDISK equates are all grouped together and centrally located for easy modification They are inserted into the BIOS following the existing equate Listing 1 DELSEND EQU DOLSPT EQU 28 40 MDISK equates s MOISKSVERS EQU 50 MOPORT EQU 030H CHIPS EQU 4 DELCHR EQU OE5H ZBANK EQU 000000008 MDISKLED EQU 100000008 MDIRSIZ EQU 128 BLKS Z EQU 2048 3 MDISK allocation block size MOSCKS EQU 0 No directory checking required MDSALV EQU 60 3 Max 472 2k disk blocks jeupmonaees End of modified inserted code 2 22ss ss sssssssezEsE55
100. ey have sold plenty of 68K boards and operating systems They are not getting rich but then they never planned on it I had the feeling that everyone felt the success of the HTPL and HT68K were going just about as expected and this next year should see some major changes in their favor One person I was talking to had a STD bus system running an 8086 but the overall performance was rather poor so they have switched to a 68K CPU board This change in design makes me feel the reason for the low feelings at the SOG were feeling that the PC Clones had just about destroyed the computer industry I think many peoplehave resigned them selves to using the inferior product to do jobs more ideally suited to other systems A few people who don t really need to stick to the Intel product line have changed over to the 68K line and are much more optimistic about their future I know personally I have little desire to deal with the PC Clone market and feel that it has been invaded by suede shoe used car salesmen If you have been following my columns for the last year you will know that I was in a master s program No more it has been completed This means two things I can complete all those projects I put aside and you have been waiting for me to complete and I now know enough NOT to become a computer teacher in the school system I did get what I wanted out of the program which was learning how to teach computer sciences as well as
101. f such an alias already exists it will be read in Otherwise it will be created M allows one to specify either a normal alias or a VALIAS style recursive alias one that clears the entire multiple command line buffer before it is run In an earlier TCJ column J described how one would use this kind of alias for certain kinds of recursion The P rint command will send the screen display of the alias script to the printer R will let one change the name assigned to the script being edited so that a script can be read in from one alias and written out to a new alias S saves the current script ina file with the current name Undo will ignore any editing that has been performed on the alias and let the user start over with a fresh copy of what was read in from the file originally X will ter minate operation of SALIAS without any prompting SALIAS has an alternative mode of operation entirely from within the interactive edit mode All of the functions that can be performed by commands in command mode and some others as well can be performed using control character sequences directly from edit mode These commands are as follows In all cases the first character for example K is a control character The second character can be a control character or a regular character in either upper or lower case KS Save the alias under the current file name KD Done editing save the file and then clear the edit buff
102. fied it was rather easy to solve Now when the background wants to communicate with the floppy disk controller it first turns off interrupts then poils the main status register of the floppy disk controller The contents of the register indicate whether the controller is busy or idle If busy the background re enables interrupts and waits If idle the background completes the task at hand and then enables interrup ts This guarantees that the foreground and background never talk to the controller at the same time Another problem discovered in testing concerned exception handling The problem occurred when an attempt was made to read on a disk drive that did not have a disk in it The oid single density system reported the error to the console and waited for a disk to be inserted the double density system was to do the same Table 3 Foreground Background Fiags Flag saueesazces Read Write Pending Retry Recal Ibrate Density Copy Meaning When Set all flags are set when true Read data to buffer from disk Set by background cleared by foreground Write data from buffer to disk Set by dack ground cleared by foreground Data in the write buffer has not yet been fiushed to the disk Set and cleared by background Unsuccessful read or write operation detected Retry In progress Set and cleared by foreground Recallbrate of disk drive In progress Set and cleared by foreground Density check In progress Set and
103. g those two characters to the BIOS CONIN routine NuKey sends the string DIR lt return gt to the BIOS and your screen displays a disk directory because you pressed the F function key For any IOP to pass the intercepted call back to the BIOS there has to be an internal jump table placed somewhere in the BIOS The IOP will know the starting address of this table and just add multiples of three to this address to get where it wants to go During the cold boot the BIOS must initialize the IOP area with a DUMMY IOP This is needed because the Jump Table at the start of the BIOS was modified to pass some calls to the IOP There had better be something there in the IOP area to han dle these calls At cold boot we load a primitive IOP which sim ply passes all calls back to the BIOS through the internal jump table we placed in the BIOS If we were to load any IOP into its reserved memory it would overlay the DUMMY IOP Then the newly loaded IOP would handle all BIOS requests for I O If at some time we no longer wish to have this IOP active the only way to de activate it is to load another IOP over it If we do not want any IOP to be active we load the DUMMY IOP into the IOP reserved memory With the DUMMY IOP loaded the BIOS acts like a standard one To create a DUMMY IOP file boot your system and do not load any IOP so that the BIOS generated DUMMY IOP is resident in the IOP memory area Invoke DDT or equivalent and enter the follow
104. ght it was too hard to write a normal compiler The first time I ran the Byte sieve it took 43 seconds After doing all the reasonable things that I could to speed it up it still took 9 6 seconds I started letting many keywords compile native code and then I realized I knew how to write a compiler if I could just get rid of the Forth syntax All it needed was an expression parser and some BASIC like keywords that would compile the run time code I first used a recursive descent parser and the Sieve time 26 dropped to about 4 seconds That parser was too dumb I couldn t easily remove the unnecessary pushes and pops or take advantage of some of the 32000 instructions For example a smart parser would translate IF inti lt int2 into CMPD inti int2 BGE xxx xxx disp to else clause which doesn t even use any registers I wrote a more flexible par ser that produces code that cannot be improved with hand assem bly assuming fairly simple statements like those in the Sieve program The compiled BASIC version of the sieve program oc cupies about 114 bytes and runs in 1 74 seconds 32016 7 16 Mhz I couldn t measure the compile time This rendition of the Sieve uses a call to the BASIC STRINGS function to fill the array because in this system strings and byte arrays are synonymous At about this point my experimental system reached a dead end because it was not self generating and the commercial cross assembler
105. had too many problems Before continuing I had to write a new cross assembler Before I could do this I had to write a new Z80 assembler because all the Z80 assemblers that I had were too slow I m replacing the Forth system from the ground up starting with a native 32000 assembler as the core This assembler is to grow into an operating system and high level language com piler but no matter what it becomes it will always also be an assembler so that it can compile itself in one quick pass at any stage of its development The philosophy of usage of this system is different from that of most commercial compilers It is not for the development of commercial products that are to be distributed in opaque form It is for the user who wants to develop his own programs expecially in applications where there is no such thing as the final version of the program These might include scientific computations or laboratory research experiments It is also for the user who would like to develop the system itself into a different kind of operating system or language compiler It is expected that the compiler will always be in the computer and that the programs will always exist in source form Programs will view the system as something like a module in Modula2 and will call system resources with normal function or procedure calls Programs can be stored and loaded in compiled form as long as the system is not changed If the system is changed then any program
106. hanging the value of FUNDEL NuKey can accommodate inter character delays from 0 to 254 milliseconds The default setting is 35 milliseconds The second parameter is called CTLDEL This parameter is used to tell NuKey how many false console status deceptions to provide This feature is used to fake out certain application programs Let s say you define a particular function key to senda The Computer Journal Issue 30 complete command string and filename to your word processor As soon as the word processor loads it flushes keyboard input and some of your commands or some characters from the filename will disappear Setting the CTLDEL parameter to some number other than zero will cause NuKey to respond false toa console status request after sending a carriage return so that the word processor will think that it has successfully flushed the keyboard buffer and no characters from the re defined function key will be lost The default setting is 8 deceptions The range is from 0 to 254 The third and final parameter is called KEYDEL Some ap plications programs flush the keyboard after every character Just as the above CTLDEL function provides for false console status after a carriage return KEYDEL provides for false console status between individual characters The default setting is 2 deceptions and can be changed from 0 to 254 I personally have experimented with these values but can honestl
107. he data in the application program s buffers This means that if you view add or delete NuKey definitions while you are running an application program you may have to make your application program re write the screen after you are The Computer Journal Issue 30 done with NuKey Saving Definitions to Disk There are two ways to save NuKey definitions to disk You can invoke NUKEY COM by just typing NUKEY lt return gt This will bring up NuKey in the menu mode Simply follow the menu choices The alternate method is to invoke NUKEY COM and pass the parameters from the command line Type NUKEY S NUKEY IOP lt return gt to save the current NuKey definitions in to the file called NUKEY IOP As with any ZCPR3 utility the command NUKEY will display a short help screen Restoring Definitions From Disk The ZCPR3 loader program LDR COM is used to load previously saved IOP files into memory Just type LDR NUKEY IOP lt return gt Deactivating NuKey Completely As I stated in the first part of this article in order to deac tivate an IOP anew IOP must be loaded on top of the old one If you do not want any IOP to be running you need to load a dummy IOP This dummy IOP is just a series of JUMP in structions which are loaded into the IOP memory segment They make the IOP look just like it did right after cold boot when your BIOS initialized the IOP area You can create a DUMMY IOP file using a debugger like DDT
108. he keys press the DEFine key If the EXTend function will be used with this key press the EX Tend key next Then press the key you wish to re define Now enter the character or characters that you wish this key to generate The DEL RUB or backspace keys can be used to correct your typing mistakes while entering the characters If you want a carriage return at the end of the character string you must enter it explicitly It will appear as M on the screen Press the DEFine key again to end the definition To delete an old definition press the DEFine key If the EX Tend function was used with this key press the EXTend key next Now enter the character whose definition you wish to delete The DEL or RUB keys will delete that definition To display the currently assigned definitions press the DEFine key twice A list of definitions will appear on the screen The assigning of new definitions deleting of old definitions and viewing of current definitions can be performed at any time even while you are running an application such as a word processor or spreadsheet There is a minor drawback to this and I personally feel it is very minor In order to see the definitions you have to display them on the screen The application program does not know that NuKey is writing information to the screen and NuKey may be writing over some data being displayed by your application NuKey is only writing over the data displayed on the screen and not over t
109. he reload value are set to the log in terval The flag is checked very often When the flag is found set a log record is generated and recorded After the logging is done the timer flag is cleared and the wait for the next time proceeds A series of sequential events can be controlled by a single timer if a state variable is used or a series of times can be used When the flag for the first timer is set the action for that flag is done Then the flag for that event is cleared and the timer for the next event in the sequence is started Eventually the time for the first event is started and the cycle starts all over again In this case each timer is acting like a one shot that triggers the next one shot in the series This has been a short discussion of how to time various even ts with only a single hardware timer The techniques will work on any processor but are especially well adapted to the 68xxx family With this type of programming it is possible to trade the faster speed of the 68000 for less complex less expensive hardware Also by having a simple generic timer routine that can be inserted like a hardware block it is possible to create larger more complex programs without greatly increasing the time needed to debug the routines involved By having the action part of the routine separated from the timer part it is also easier to get less overall variation in timing and almost eliminate time drift 39 Reader s Feedback Continue
110. heck for the copy flag If so copy 128 bytes from the holding buffer to the write buffer Step 9 If the write flag is set start the write operation Step 10 Return to background mode Problems To Be Avoided All sorts of problems can arise if the read buffer and the write buffer ever contain the same sector This would have the same effect as two files on the disk using the same sector Un predictable and unrepeatable results would follow Therefore great pains are taken to assure this never happens If you are not careful there are several scenarios where this could occur For example on a predictive read ahead the write buffer could con tain the next sector beyond the current read buffer sector All these potential problems are solved by assigning higher priority to the write buffer Every read must check the write buffer first to be sure the sectors are not the same Every write must check the read buffer and if it contains the desired sector transfer its contents to the write buffer then mark the read buffer empty The major problem encountered during the system testing phase turned out to be an unanticipated critical section problem The old single density system never had a critical section because concurrent processing was not attempted The critical section in this implementation occurred when both the foreground task and background task attempted to interface with the floppy disk con troller Once the problem was identi
111. ign to a file requiring more space or there is no free directory entry to store the file s name and its list of allocation units Choose your directory size carefully your disk is full if you run out of directory entries even if there is free space on the disk The CP M operating system is logically partitioned into three separate functional modules the Console Command The Computer Journal Issue 30 Processor CCP the Basic Disk Operating System BDOS and the Basic Input Output System BIOS One of the strengths of CP M is that all the hardware specific input output drivers are located in the BIOS These three modules communicate through a standard set of subroutine calls Since this is a hardware specific upgrade project only the BIOS need be modified Prudent BIOS modifications result in complete upward compatibility Of the 17 BIOS subroutine calls only seven relating to disk operations need be described here only two of the seven require any significant changes Parameters are passed to these subroutines through the processor registers Any results are also returned through the registers e SELDSK Specifies which disk is referenced in all future disk subroutine calls This routine need not be altered to upgrade to double density e HOME Move the head of the disk specified in the last SELDSK call to track 0 This routine need not be altered to upgrade to double density e SETTRK Specifies which track is refere
112. ing commands AO0 D00T lt ret gt MECOO FIFF 100 This moves the DUMMY IOP from ECOO to 100 c Get out of DOT with contro C AO gt SAVE 6 DUMMY IOP Save 6 pages to the disk file DUMMY 10P The above sequence created a copy of the BIOS generated DUMMY IOP which resided in the IOP reserved memory area in to a disk file It should be noted here that if you make any changes to your BIOS which cause it to change size or change the location of the internal jump table you will have to create a new copy of the The Computer Journal Issue 30 A fast 1 megabyte RAM disk for your AMPRO Z80 Little Board Fast RAM workspace greatly speeds up disk intensive operations like wordprocessing database access and program development 575 gt 5 25 printed circuit board plugs into your AMPRO Z80 socket Add standard 256K RAM chips for up to 1 megabyte of extended RAM MOISK driver sottware enables the extended RAM to be used as a solid state disk drive compiete with system track for instant warm boots Driver software supplied as boot time utility for use with standard AMPRO systems using current BIOS version 3 8 Source code tor BIOS driver inserts also inctuded for custom instaliations e Includes extended RAM test utility e Requires 5vdc at 60 amp via standard disk drive power connector Little Board must be modified to replace the 64k RAM chips with sockets and to add one jumper Complete instructions included
113. ings to be usable It takes the same amount of time that the CP M LOAD utility takes to translate an equivalent HEX file to a COM file Thus my assemblers and my 32HL system do not generate any intermediate files they use IN CLUDE to accomplish linking at the source level My Z80 assem bler retains the option to make a HEX file and retains the option to perform two passes My cross assembler eliminates the capability to perform two passes or to make a HEX file My 32HL system further eliminates the capability to make a PRN file I m hoping my proposed debugging scheme won t need the PRN file I have found myself getting into the habit of not saving the COM file because it takes longer to type the commands to save the COM file on two floppies than it takes to assemble a new one later Modula2 fixes some of the bad syntax of Pascal and allows some ways around the roadblocks but the excruciatingly huge number of files to keep track of renders the thing unusable to me one programmer per project It s a good emulation of the cassette days when you had to keep track of files without a direc tory One of my ideas for the file system is to let the directory be compatible with the symbol table so that the expression parser can access disk files the same as other variables The statement A BI C would not care if B is an array in memory or if it is a disk file No opening or closing syntax is needed no functions are needed and none of th
114. is a trade off between more sof tware and more hardware to accomplish a given task Using more software means the unit cost will be lower but it also means there may be more developement costs involved Software needs less board space than hardware does and it uses much less power The purpose of a standard software item is to provide the same con venience that an LSI part like a UART or PIA does You can use them and you don t have to design the parts each time Also by reusing the same parts you can get more done with less effort and fewer bugs If the time interval is very short less than a millisecond then it is hard to use software instead of another hardware timer If the time interval is longer than 100 msec and the resolution is 10 msec then there is no reason to use hardware With a software timer you can have as many timed intervals as you want but you only pay for one hardware timer The internal timer on the 68681 used in the HT68k is an example of this When doing timing I like to divide the servicing of the timer interrupt from the actual action that is performed The goal is to spend as little time as possible inside the interrupt service routine This lessens the chance of losing an interrupt and makes more time available for the time critical services like serial input devices To do this I use flags to indicate that an operation is to be performed A non interrupt loop tests the flags and does the operations indicated IN
115. ite amp Cortesi and look forward to learning Z80 assembler Turbo Pascal and BDS C so it fascinates me to read about how you operate ditto Dave Thompson s editorial comments in Micro C even if I m not there yet Frankly I know my little Z80 CP M world is on its way out so I want to preserve as much of the literature surrounding it as possible for when I do get around to learning it all I don t especially look forward to more User Friendly for think I ve got lots to learn just from my little 8 bit system and that s really what it s all about isn t it Anyway I do love going thru all this stuff that s really much over my head But what you say about us providing our own Technical Support by sharing our knowledge really appeals to me it s one big factor that attracted me a long time college professor of English into computer owning I don t really dare say into computing So I have no gripe with Perfect Writer I don t really aspire to own the latest or fanciest but I do look forward to completing the initial course of study I ve embarked on and your free wheeling editorials really help share the flavor of what it s all about Also it s a secure feeling knowing I have all this reference material including Dr Dobbs amp Computer Language for my future The Computer Journal tssue 30 perusal and learning So probably Pm n
116. k blocks so we will set the highest two bits in ALO to 1 The final two words are the check size CKS and the system track offset which is the number of reserved system tracks Since we do no directory checking CKS is zero We have reserved one system track so OFF is set to L Physical Driver Table The next BIOS insert also shown in Listing 2 follows the AMPRO label PHYTAB and contains the MDISK driver number the default MDISK drive offset and the MDISK type byte AM PRO allows for up to 7 drivers and is already using drivers 1 to 3 We have selected driver 7 for our MDISK driver in order to keep us out of the way of possible expansions The next byte contains the physical offset from DPBASE in the DPH table in the high 4 bits and the physical device ad dress in the low 4 bits Since we re using drive F as our MDISK drive letter our offset is 5 since A 0 If you re using a different MDISK drive this offset must be changed and instead of modifying the listing for drive F you must modify the listing for the drive letter you have chosen We have no physical device ad dress so the low bits are 0 giving us an offset of 050H The type byte contains information about the density number of sides the sector numbering the track count the block size and the sector size When you work all that out according to the infor mation comments in the AMPRO BIOS you get a type byte of 4 which descri
117. kage that the old MicroPro used to charge an extra 500 for No longer will the hobbyists have to ferret out all the patch points for the program though I am sure there will be plenty of areas nevertheless to keep us entertained ZAS ZLINK Another exciting development is release 3 of ZAS ZLINK Echelon s assembler linker and librarian package As many of you may know most serious programmers Echelon team members included have had little but scorn for ZAS in the past It was a strange and unreliable assembler But Echelon has now really made good on ZAS They did it right this time They did not go back to the original author and try once again to get him to fix it instead they brought in the highly competent Al Hawley Though I am sure it is still not perfect what program is it has correctly assembled all correct code that I have fed to it And gone are its former irritating and unique idiosyncrasies like square brackets instead of parentheses in arithmetic expressions ZAS will now handle just about any code written in some semblance of standard assembly language It sup ports a rich set of pseudo ops making it tolerant of common variants ZAS and ZLINK are also at long last honest Z System tools as befits an Echelon product They recognize named directory references for all files and they communicate with the Z3 en vironment and message buffers With an appropriate editor it is possible to build a code developm
118. king Deblocking Considerations Disk Sector and Buffer Size My CP M system had been used for several years and ex perience had shown the resource most often in short supply was disk space I decided floppy disk space would be maximized but that reduced the space available to application programs Ed The program space is reduced because of the space taken by the larger disk buffers Not to worry if an application program required more memory the old smaller single density version could be used The larger the physical sectors on the disk the greater the storage capacity because there are fewer inter sector gaps to waste space The sector size was chosen to be 1024 bytes This size resulted in nine sectors per track 76 tracks per disk for files and the directory and produced the maximum possible capacity 684K for a single sided double density floppy disk The operating system disk buffers and the sector had to be the same size because any disk read or write always transferred an entire sector Number of Disk Buffers In general increasing the number of disk buffers increases throughput However in this system the buffer size is so large that too many buffers would have unreasonably increased the operating system size I observed that most programs would read from one file while writing to a second file for example assem blers If there were only one disk buffer thrashing could be a problem It seemed that two 1024 byte buffer
119. king these changes yourself just send me a bootable disk of the system you are currently running Please indicate your system configuration hard disk floppy disks BIOS options desired I will return the disk with the new BIOS for IOP support and the DUMMY IOP file Please indicate whether the disk is 48 or 96 tpi Rick Swenton 19 Allen Street Bristol CT 06010 Editor s Note In view of Rick s very generous offer it would only be fair to include some money for his time and postage Now that my two main systems the Ampro Little Board and the Heath H89 are running NuKey IOP I don t know how I have lived without it for so long Joe Wright s NuKey IOP program really makes your keyboard a pure joy to use Until now Ampro Computer users could not take advantage of the IOP applications that other users were enjoying for some time Now you can make those changes yourself raise your level of understanding and install a great keychanger on your system at the same time i Exploring the fascinating world of Z System encourages all kinds of learning activities by its users The original BIOS authors and systems integrators of the late 70 s and early 80 s never imagined in their wildest dreams that a home computer hobbyist would be modifying and enhancing the BIOS himself This kind of activity will probably not take place in the 16 bit world for a long time if at all Only in our 8 bit CP M compatible world 18 could we have a
120. ll do everything The calling program may be able to use this time effectively If the write is to a double density disk the record written may be in the write buffer the read buffer or out on the disk Step 4 Find out if the sector that contains the record to be written is already in memory Apply the unallocated unit algorithm to update the unallocated unit write type flag If the sector containing the record to be written is in the write buffer transfer the record and go to step 8 Step 5 Since the write buffer does not contain the record if a write is pending start the foreground write and wait for it to complete Build the floppy disk controller command string Step 6 If the record is in the read buffer transfer the read buffer to the write buffer mark the read buffer empty transfer the record to the write buffer Go to step 8 Step 7 The sector containing the record to be written is not in memory Determine if a sector preread is necessary by checking the unallocated unit write type flag If no preread is necessary go to step 8 Otherwise transfer the record to the 128 byte holding buffer and set the read and copy flags Step 8 If this is a directory write set the write flag reset the write pending flag and start the foreground write If this is not a directory write set the write pending flag Note the foreground clears the write flag when the write is complete Step 9 If the read or write flag is
121. ll the information at our finger tips to do whatever we want whenever we want Only in our 8 bit CP M compatible world do we have support companies like Echelon expert programmers like Richard Conn and Joe Wright and the volunteer efforts of the Z System user community most especially the ZSIG organizers Jay Sage Bruce Morgen Richard Jacobson and many many others I wish to thank Joe Wright for his assistance in the im plementation of the Ampro BIOS IOP support The following items are available from Echelon Inc 885 N San Antonio Road Los Altos CA 94022 415 948 3820 ZCPR3 The Manual is the reference manual for ZCPR3 and its utilities 351 pages typeset bound book 24 00 Z System Users Guide is a how to step by step tutorial and an excellent complement to The Manual above Loose leaf 95 pages 14 95 ZCPR3 and IOPs is the standard reference manual for im plementing IOPs and operating the associated utilities 50 page loose leaf manual 9 95 Three IOP programs are available NuKey is an advanced function key generator 39 95 Input Output Recorder I OR redirects input output to from console printer disk file ZRDOS Plus required 39 95 Print Spooler B Printer background single file print spooler ZRDOS Plus required 39 95 ALL THREE IOP Programs above are available for 89 95 ZRDOS Plus an improved replacement BDOS is 59 50 ad ditional Prices are subject to change Source
122. lls You must log in separately for each system and leave a message for SYSOP requesting TCJ access The Computer Journal Issue 30 TCJ subscribers will have access to four named directories YOUNEED ZSIG SB180 and TCJ The YOUNEED directory holds the minimum utility toolset required to take full advantage of Lillipute Z Node ZSIG contains all the programs approved by the ZSIG software librarian Jay Sage and his software commit tee SB180 has programs documentation and bug fixes relating to the SB180 an HD64180 based computer sold by MicroMint It will also contain all updates for Malcom Kemp s brilliant new operating system for the SB180 called XBIOS TCJ tiie ZCPR3 named directory not the magazine will contain files uploaded by Art Carlson including listings from TCJ articles With your assistance Art Carlson and I will be able to determine what direction to take with the TCJ named direc tory We will need your feedback to accomplish the task An enormous amount of software is available on Lillipute Turbo Pascal material takes up about 4 megabytes Several megabytes are occupied by the modem programs Mex and Imp along with their overlays Far more space is devoted to ZCPR3 ZCPR33 and supporting documentation than to any other single group of files One of the new sections is devoted to Modula 2 with almost a megabyte devoted to Wirth s successor to Pascal Two of the most popular sections are WORDPRO and
123. m SALIAS Screen Alias Editor When I released VALIAS visual alias editor a couple of years ago I wrote in the documentation that someone should please extend it to full screen operation it only supported inser tion and deletion of complete lines Paul Pomerleau s BALIAS allowed full WordStar like editing of alias scripts but it treated the entire multiple command script as a single line I much preferred the structured presentation of VALIAS with each command on its own line I suggested that VALIAS should be ex tended to automatically indent the lines to show the nesting of flow control commands It has been a long wait but finally the wait is over Rob Friefeld from the Los Angeles area contact him on Al Hawley Z Node 2 has released SALIAS screen alias editor and what a beauty it is You will no longer find VALIAS on any of my disks With SALIAS alias scripts are displayed and edited rather a if they were WordStar text files Each individual command i displayed on its own line except that long lines can be continued on the next line by entering a line continuation character control p followed by at the beginning of the continuation line i SALIAS works in two basic modes One is the commanc mode like that in VALIAS In command mode the status line at the bottom of the screen displays the following prompt CMD Clear Edit Format indent Load Mo
124. m containing medical sof tware The people who had control of the money at the time did not buy under any contractual agreements They basically got a system software a few hours of training operators manuals and a com plex mess They later discovered plenty of problems and hired my friend to help them out They have since discovered how little they got for their money and how much more it may cost to keep the system running The original plan was to use the consultant for help but he is now charging 50 dollars an hour which they can not afford they also need to update the software package at close to 1000 and can t do that till they send someone to a training program which costs 400 What this whole problem points out is the typical problems businesses are facing when they try to computerize The first problem was allowing people who know nothing about computers to buy them These people didn t use a contract that clearly stated what the system will do what is included in the purchase and what kind of support and for how long The hidden cost might not have been listed but experienced purchasers have learned to include at least one free update in their contracts The agent or consultant was not checked for his track record in fact this was the first and only such installation this person has done The consultant really didn t have either the experience or Continued on page 47 The Computer Journal Issue 30
125. mers The single hardware timer on the ht68k can be used in this manner to provide a variety of timed intervals A common method of using the timer flags is to have a single very large loop for the main program The loop is a series of tests of the various flags that have been defined If a flag is set the ac tion routine that it was timing is done and the flag is cleared For physical events the accuracy will be good enough in most cases As more timers are added then the accuracy of the timing for each event may be less then when there are few timers One ap proach to this part of the problem is to have the most time critical event flags at the start of the flag test loop Instead of testing the next flag a routine that takes a long time to execute can go back to the top of the test loop This would insure that only one long routine gets executed each time through the scan loop The same loop can also respond to flags set as the result of other kinds of in terrupts or events An example of using a software timer is in a communication program When a reply is expected the count value can be set to the maximum amount allowed the flag cleared and the reload value set to zero The flag is tested and if any interval causes it to time out then the flag will be set This can be used to abort a call if there has been no activity for a certain time period An example of using a periodic counter is a logging or repor ting system The counter and t
126. message is displayed We need a way to tell whether we already have a disk directory so we will create a label file when we boot the operating system We will call our label file MDISKXX RAM where XX is the MDISK software version number 50 in this case By using a leading dash in the filename we accomplish several things This way the label file usually en ds up in the upper left corner of the direc tory listing if your directory utility gives you a sorted listing We also make it com patible with many disk catalog utilities and with the very useful ZCPR3 named directory utility LDSK which can create a named directory NDR file from all selec ted user areas that have label filenames beginning with a dash LDSK will ignore the extension RAM and create the named directory MDISK50 To do our entry test the MDTEST routine first looks at the first MDISK directory entry for the label file MDISKS0 RAM If it is found we will assume that a directory already exists and that we can tell the operator so and con tinue with the boot sequence without doing any more setup work If it is not there we assume we will have to create a new directory which will wipe out any existing directory information To protect our directory from ac cidental deletion on cold boots it is im portant not to accidentally erase the label file so we will make it a read only file To p
127. n One would have predicted the fragmentation would be 2K x 31 or 62K additional but the final result was 67K 256K 189K This difference was caused by the large number of small files less than 1K on the disk Speed The file handling capabilities of the system were greatly enhanced Two benchmarks were run a strictly disk to disk copy test timing and an assembler test timing The results are outlined in the table below Single Double Density Density Predictive Read Anead Off On Copy 4 30 2 38 2 20 Assembly 1 45 1 00 0 55 Min Sec 12 The assembler test was the assembly of this BIOS portion of the operating system The file copy was the duplication of a disk on one drive to a blank disk in the second drive There were 31 files on the disk and the total space filled on the disk was 189K These figures show the new double density system was about twice as fast with 10 of the improvement due to the predictive read ahead Compatibility The new dual density system is now being used regularly M80 L80 WordStar SuperCalc ZSID and DESPOOL run successfully and no compatibility problems oc cur Two programs had to be re written but it was known beforehand this would have to be done These two were the disk format program and the system loader program The format program had to be modified to format double density disks The system loader program which formerly loaded the operating system onto tracks 0 and 1 was modifie
128. n be used as either single density or double density When work began the single density system had a single 128 byte disk buffer with no overlapping processing the total storage capacity direc tory plus files being 243K bytes per floppy disk When work was completed the total increase in throughput was approximately 100 with 90 due to the larger disk buffers and concurrent processing and 10 due to a predictive read ahead scheme The total disk space available to files and the directory was increased to 684K This performance increase did not come for free however The total operating system size increased by 3K from 7K to 10K with 2K of the increase due to new read and write disk buffers Introduction to CP M s Disk Organization The CP M operating system is a single user system designed to be run on an 8080 or any of its descendants The CP M system is described in detail by many books and publications so only the important file system specifics are presented here For further in formation consult one of the publications listed in the bibliography CP M performs all disk input output in 128 byte logical units called records Occasionally when describing a single den sity floppy disk system the terms sector and record have been used interchangeably because the physical disk sector size is also 128 bytes On a double density system the sector size is never 128 bytes and the two names are not interchangeable I will always us
129. n enter the breakpoint address symbolically if the program has a label at the appropriate place When in the stopped condition you can also execute the ROM monitor do commands reenter 32HL and continue the stopped program Any global variables or procedures that are created during the compilation of a source file or a keyboard line are available for use by subsequen tly compiled source files or keyboard lines This thing is more in teractive than Forth because at the keyboard we can execute FOR j 0 TO 23 lt statements gt NEXT j but in Forth you can t do that unless you use a colon definition to make that line a new keyword then execute the keyword then forget the keyword On the implementation side all pre defined words including DOS commands and library procedures are to be in the main state machine Another state machine that handles operands will con tain the library functions User defined words go into a heap area and an array of pointers is used to find the symbols with a binary search At the end of a procedure the symbol table is truncated back to the point where the procedure started Therefore the binary search is performed on clumps instead of the whole table at once The source text buffering uses a method that allows the parser and state machine to run blind without checking for the end of the buffer Because the intended usage of this thing demands rapid compilation there will be no optimization and no 27
130. nced in all future disk reads and writes The standard Digital Research BDOS issues spurious SETTRK commands to track 0 and but never follows with any reads or writes For this reason it is better to actually seek the read write head to the track required only when the read write command finally arrives This routine need not be altered to upgrade to double density e SETREC Specifies which record is referenced in all future disk reads and writes Note this is the logical record num ber On a single density system this is also the physical sector On a double density system this number must be converted by the BIOS to the physical sector and offset into the sector While track numbers start with 0 sector numbers start with 1 This routine need not be altered to upgrade to double density e SETDMA Specifies the memory source destination address for all future reads and writes Note the length is always 128 bytes This routine need not be altered to double density e READ Performs the read of the record specified in the previous calls to SELDSK SETTRK and SETREC into the memory destination specified in the last call to SETDMA e WRITE Perform the write of the record specified in the previous calls to SELDSK SETTRK and SETREC from the memory source specified in the last call to SETDMA When a record and sector are both 128 bytes no special con sideration need be taken just write the record to the disk When a sector cOnt
131. nd send your check or money order to MicroPro Order Update Department P O Box 7079 San Rafael CA 94901 7079 Or call toll free 800 227 5609 Ext 762 Allow 3 4 weeks for delivery Name Osborne format 5 1 4 disks CP M Release 4 89 00 Address Kaypro format 541 4 disks Tyee 5 Generic8 disks_ n o aor oan City____ State Zip SSS Apple format 5 1 4 disks available October 87 Shipping Handling 5 00 Company Name WordstarSerialNo _________orincludetitlepage Total Telephone re ee eee of your WordStar Reference Manual Only these states require sales tax CA GA IL MA NJ NY OH TX and VA WordStar and MicroPro are registered trademarks of MicroPro International Corporation CP M is a registered trademark of Digital Research Inc All other product names and trademark information are listed for purposes of description only 2 1987 MicroPro The Computer Journal Issue 30 9 Step 4 Build the floppy disk command string set the read flag and start the foreground task Step 5 Wait for the foreground to complete Note the foreground clears the read flag when the read is complete Step 6 Transfer the record from the 128 byte temporary holding buffer to the DMA destination If your DMA hardware allows the read could transfer directly to the final destination my DMA controller can t Step 7 Restore the stack and return to the caller But if the disk in the drive is double density
132. ng add entry to list check an ordered list remove an element from a queue factorial of a number reentrant and recursive scaled indexes This Fall intend to sit down with this book and Hawthorne s 68000 Tiny Giant and learn all about 68000 assembly language Suggested Reading The following books which are in our queue for review appear worthwhile More complete reviews will follow but this preliminary listing is to let you know that they are available in case you have immediate needs for them Your reviews and or comments on Specialized technical books are welcome along with suggestions on useful books which should be inculded in future reviews We intend to limit our reviews to advanced or specialized limited distribution works and not to duplicate what is being already covered in the mass market magazines File Formats For Popular PC Software by Jeff Walden Published by Wiley Press ISBN 0 471 83671 0 Listed as A Programmer s Reference this book is part of Wiley s IBM PC Series It includes information on the disk file structure for Lotus 1 2 3 Symphony Ability dBase Data Interchange Format DIF MultiMate MultiPlan and the SYLK File Format IBM Plans Super Calc3 and the Super Data Interchange VisiCalc WordStar v2 2 3 31 and Wor dStar 2000 l r I found the DIF very helpful when converting a mail list received on 9 track tape and I wish it had information on the Condor file stru
133. ng system we call the locally distributed multiple processor system MPS These systems consist of closely located independent CPU memory pairs linked together by a communication subsystem Another book for my required reading list 45 Writing MS DOS Device Drivers by Robert S Lai The Waite Group Published by Addison Wesley ISBN 0 201 13185 4 A high level book with a lot of very good information about a very important subject The book is well written and well organized contains useful working programs as examples disk available for 10 and the necessary information on BIOS interrupts t Memory Resident Programming on the IBM PC by Thomas A Wadlow Published by Addison Wesley ISBN 0 201 18595 4 Covers how to write your own TSR Terminate and Stay Resident programs and includes a very good section on the IBM ROM BIOS Services I ve always wanted my own special TSR monitor debugger and this book shows how According to the back cover a disk is available from Addison Wesley Looks like a good combination with the device driver book above How to Write a Useable User Manual by Edmond H Weiss Published by ISI Press ISBN 0 89495 052 5 Writing is an art and writing user manuals is a very special art If you want to write a decent manual you have to know more than just how to program and this book has the needed information on the often neglected aspects of writing a user manual C Programmer s
134. nn s ZCPR3 replacement Con sole Command Processor CCP When they created their Basic Input Output System BIOS they built in the required routines to initialize the special reserved memory locations needed in a ZCPR3 system At the time the BIOS was written and subsequen tly revised ZCPR3 I O Packages IOP were not widely used This was because IOPs were not really understood by the masses and IOP software was not readily available Many users did not feel that they needed the features that an IOP provided such as console capture to disk redirection of console printer modem I O or operating devices in tandem Richard Conn s original con cept of an IOP was to remove the I O routines from the BIOS and place them into the IOP segment In this way many different IOP s could exist and be loaded on demand Each would provide you with custom specialized I O tasks Because IOP s were not very popular Ampro chose not to allocate space for an IOP in the reserved memory set up by the BIOS at cold boot time Things chance very fast in the 8 bit world Suddenly IOP s are becoming very popular Echelon the official source of ZC PR3 and a full line of Z System products now has three full featured IOP s available If you use Ampro s standard BIOS you can not run any of them without modifying the BIOS Users of the Micromint SB 180 were running around left and right using IOP s and rubbing my nose in it Micromint had chosen to provid
135. nsiderations by Gilbert Held Published by John Wiley amp Sons ISBN 0 471 91280 8 Data compression is very important for data communications and this book provides information on how to select the optimum method for different ap plications Reader s Feedback Continued from page 40 e PCXT 8MHz clone with EGA Wonder RLL disk controller and 2 Meg board e S 100 bus Z80 system with 8 drives e Single board wire wrapped Z80 system with 8 drives S 100 bus 64180 system with 128K RAM 8 drives and 24 Meg 14 Win chester I want to see someone write a non pre emptive task switching CP M system so you can have the editor and compiler in RAM always and just switch between them as needed I d write it but I don t have the time Anyway I m glad you folks are still publishing for the CP M audience But don t get dreary about it like S 100 Jour nal B D Editor What we publish will depend on what we hear from our readers Send us a list of the subject matter for 4 or 5 articles which you would like to see published or better yet send us your article to publish Knowledge is for sharing but Sharing means that you have to par ticipate E The Computer Journal Issue 30 Computer Corner Continued from page 48 skill needed to actually perform the tasks requested of him The end result of the whole affair is a lot of people feeling taken for money that was very hard to
136. o these techniques are a much lower cost solution than using a real time kernel The Computer Journal Issue 30 The CP M Corner by Bob Blum Starting a new column for a magazine that I have never written for is a little unnerving For over four years I edited columns of this type for other magazines and as you might expect in that length of time I became very comfortable doing them The primary reason for my peace of mind though was not familiarity with the work but the responsiveness of the readers I have always depended heavily on them to provide me with their feedback on how I am doing and most importantly to tell me what type of material was most valuable to them These ideas many times became the subjects of columns As you can see my job wasn t very difficult all I had to do was listen To get this column started on the right foot I need your help The more quickly I get to know you and your interests the faster I can begin to cover the subjects most important to you Drop mea note describing your interests or maybe you have a nagging problem that seems to be insolvable I may not be able to solve it myself but I m sure one of the other readers can Have you run into a particularly good program lately Tell me about it No mat ter whether it came from the public domain or you purchased it commercially personal recommendation is always the best reason to investigate a software package for potential review And while
137. ogram When you invoke NUKEY select M from the Main Menu to create a new IOP When you are asked for a filename press RETURN and the default file NUKEY IOP will be created NUKEY IOP is a ZCPR3 segment loaded with the LDR utility Just type LDR NUKEY IOP Now you need to select your DEFine and EXTend keys Defining Your Keys When you are asked to select your DEFine key you should select a key which is not frequently used Remember that whatever key you select will no longer be available for use under any other program except NuKey A good choice for this charac ter is the back slash or the tilde I prefer the tilde because on my keyboard it requires the shift key to be pressed at the same time This minimizes accidental pressing of the DEFine key Next you are asked to select the EXTend key Here again you should select a key which is not frequently used However whatever key you select will remain available to your other sof tware After you select your DEFine and EXTend keys NuKey is ready to run All virgin copies of NUKEY IOP or whatever you name them created with NUKEY COM will ask you to select these two keys the very first time the IOP is run After they are selected they are stored within the IOP and are never asked for again If you need to change them you must create a new virgin copy of the IOP and start from scratch To assign new definitions to t
138. om MicroPro to introduce the new product As excited as I was about Release 4 I was sure that this would be the end of the line so I was quite surprised when the representatives talked about a release 5 for CP M as well as for MS DOS MicroPro speaks of itself now as the New MicroPro and indeed they sounded like a new MicroPro They are extremely solicitous of user suggestions Their upgrade policy is very generous they ll happily accept the serial number from any older WordStar or NewWord and the upgrade price of 89 for in dividuals and 79 for clubs is very attractive Echelon s special of fer at 195 for those who did not own WordStar or NewWord The Computer Journal Issue 30 before is also quite reasonable for such a high quality product I personally have not made much use of WordStar in the past preferring my roll my own do it my way PMATE text editor but I have already placed my order for WS4 if for no other reason than to show my support to MicroPro and to encourage them to stick with us 8 bitters Frankly am also quite eager to explore WS4 s new Z features Since my copy has not arrived yet I cannot give you a first hand report but what I have been hearing from others is ex tremely positive It apparently knows about the command search path and named directories of ZCPR3 and can run as a true shell The documentation included with WordStar 4 is extraordinary the equivalent at least of the customization pac
139. omputer Journal 190 Sullivan Crossroad Columbia Falls Montana 59912 or The Computer Journal PO Box 1697 Kalispell MT 59903 Address all editorial and adver tising inquiries to The Computer Journal 190 Sullivan Crossroad Columbia Falls MT 59912 phone 406 257 9119 The COMPUTER JOURNAL Features Issue Number 30 Double Density Floppy Disk Controller An algorithm for an improved CP M operating system floppy disk controller BIOS by Donald C Kirkpatrick 0 00 0 cc cccccccccsccccuccuuveeuveces 6 ZCPR3 IOP for the Ampro L B Implementing ZCPR3 IOP support for the Ampro and featuring NuKey a keyboard re definition IOP by Rick SWenton ccc ccc cscs eeeeccnesceveceanuveceunens 13 32000 Hacker s Language A discussion of how a working programmer is designing his own language with vast improvements over what is available MDISK Part 2 The software drivers for the 1 Megabyte Ampro Little Board RAM Disk by Terry Hazen and Jim Cole cccccceeceeeuneeeseeuteees 30 Non Preemptive Multitasking How multitasking works and why you might choose non preemptive instead of preemptive multitasking BY JOG Bartol ierra asadar iar aii a eae aes 37 Software Timers for the 68000 Writing and using software timers for process control projects is often more cost effective than adding hardware timers BY Joa Bartel s esre aea ie eE a ans 39 Lilliput Z Node A Remote Access System for TCJ subs
140. open a library with that name if it exists and the command C to close the currently open library They can also be renamed using the R command There are several miscellaneous commands will toggle between a built in help display and the file name display X is used to exit from VLU J is used to jump to a file is used to retag files that were tagged before some group operation was per formed and Q refreshes the screen display Future versions of VLU will include some features not yet in the present one A printing capability will be added to com plement the view functions Presently VLU cannot add files to an already existing library though it allows the user to specify the number of elements to accommodate in the library directory so that another tool such as LPUT can be used to add more files later VLU has an L command to iog into a new directory By opening a library in one directory and then changing to another one can extract files to a directory other than the one containing the library At present however the L command does not recognize a file mask as ZFILER does to restrict the files included in the display Even in its initial release form VLU is a very welcome addition to the toolbox of Z utilities and I extend thanks from all of us to Michal Carson Subject for Next Time As I promised last time this column has taken a less technical tack though I feel that it ha
141. ot a typical reader but certainly an avid one Again many thanks B T PS Just read Bill Kibler s article men tioning school teachers at least I can type but all the rest of his charac terization fits Also let me add that do have the two Bell Labs UNIX manuals and really aspire to be able to comprehend if not necessarily to actually write large systems based on this O S B T Apple User I am currently using a PCPI Applicard modified for 8MHz operation and run ning on an Apple Ile Peripherals include a 3Mb ramdisk 10 Mb Winchester Ap plied Engineering 3 6 Mhz accelerator card for 65C02 on motherboard An chor Lighting 2400 modem two 87 DS DD drives and an Appe Imagewriter I printer I have also recently purchased a Kaypro 10 83 but have not done much hacking with it other than to order an Advent Turbo ROM I am convinced that the Apple PCPI combination offers the optimum tradeoff of performance vs cost of system expansion A wide variety of peripherals are available for the Apple bus and tend to be orders of magnitude cheaper than comparable products for single board computers and or Kaypro s I have done a fair amount of contract programming for the Apple CP M en vironment device drivers mostly Early in 1987 I developed a piece of software for scheduling the operation and signal routing of 24 VCRs in an industrial set ting The development language was Tur bo Modula 2 and I probably was
142. our full screen editor Or suspend your spreadsheet to look up information in your database This is very handy in an office environment where constant interruption of your work is to be expected It s a significant enhancement to Z System and an enormous enhancement to CP M BGii adds much more than this swap capability There s a background print spooler keyboard macro key generator built in calculator screen dump the capability of cutting and pasting text between programs and a host of other features For best results we recommend BGii be used only on systems with hard disk or RAMdisk JetFind A string search utility is indispensible for people who have built up a large collection of documents Think of how difficult it could be to find the document to Mr Smith in your collection of 500 files Unless you have a string search utility the only option is to examine them manually one by one JetFind is a powertul string search utility which works under any CP M compatible operating system It can search for strings in Z sets you free text files of all sorts straight ASCII WordStar library LBR file members squeezed files and crunched files JetFind is very smart and very fast faster than any other string searcher on the market or in the public domain we know we tested them Software Update Service We were suprised when sales of our Software Update Service SUS subscriptions far
143. r any we have overlooked Apple II II IIc IIe Macintosch DOS 3 3 ProDOS Apple Computer Company CP M DDT ASM STAT PIP Digital Research MBASIC Microsoft Wordstar MicroPro Inter national Corp IBM PC XT and AT IBM Corporation Z 80 Zilog MT BASIC Softaid Inc Turbo Pascal Borland International Where these terms and others are used in The Computer Journal they are acknowledged to be the property of the respective companies even if not specifically mentioned in each occuren ce TCJ is User Supported Advertiser s Index AMPRO Computers C User s Group C C Software Classified Computer Journal Echelon Inc Hawthorne Technology Kenmore Computer Tech MicroPro Sage Microsystems East Software 88 If You Don t Contribute Anything Then Don t Expect Anything 47 Well summer is coming to an end and with it was the seasonal jaunt to Bend Oregon for Micro Cornucopia s SOG Semi Official Get together This year most of The Computer Journal s staff was present and we all had considerable fun talking and planning those next articles The entire affair had a different feeling to it this year not so festive but a bit more serious After the dinner on Saturday night everybody got into talking and planning I went to bed at 3 a m but some never made it at all The friends at Hawthorne were there Joe gave two talks and Marla gave one both very well received Th
144. r the routine until the using task is finished Because a task knows it will be swapped out the routine that gives up control can save any information that needs to be saved the swap routine needs to save only the minimum For many applications the use of nonpreemptive multitasking means that an existing single user single task operating system can be used for character I O and for disk file management In our case this means the use of K OS ONE but the techniques will also work with CP M and MS DOS A single task operating system is usually much less expensive less com plex and smaller than a multiuser system A single user system is also much more available In any multitask system it is important not to waste time that could be used by other tasks There are two main areas where time gets wasted One is waiting in a loop for a character from the con sole or for an I O device to become ready In this case the TESTIO command should be used to check for an available character and give up the machine to the next task if there is no character available Another waste of time is a timing loop To avoid this the system time command should be used and if it is not yet time to act then give up the system to the next task Implementation Now that you are sold on the advantages of using a non preemptive multitask scheme how is it done As simple as possible that s how Since everyone with K OS ONE has an HT PL compiler I will use that
145. re is a character available the character and a true in dicator are returned If there is no character available then a false is returned This causes the loop to continue until a character is available which it returns on the stack This allows processing to occur in the background while waiting for the operator to input a character After the input character is processed then the wait loop can be entered to wait for the next character In most cases there is no need to wait to output characters The BIOS on the HT 68k has a 256 character output queue If this doesn t become full then there is no wait for output because the operating system merely places characters in the output queue If there are several tasks running and a lot of characters need to be sent out then a small number should be sent each time the task sending the characters is active This allows the other tasks to run while K OS ONE sends the characters from the output queue un der interrupt control If a larger buffer is needed then the BIOS Continued on page 28 The Computer Journal Issue 30 Software Timers for the 68000 By Joe Bartel Hawthorne Technology In most process control projects and many interactive programs there is a need to sequence and time operations These are some techniques have developed over the years and have converted into 68000 assembler code A similar method will work with almost any other processor m mFor most projects there
146. res of SALIAS There is an additional status line at the top of the screen It shows the name and version number of the program the type of alias nor mal or recursive the number of characters free and the current name for the alias The free character value is calculated by subtracting the number of characters presently in the script from the number of characters allowed in the multiple command line buffer This computation is not infallible There are some parameter ex pressions such as D that take up less room when expanded so it is possible that SALIAS will refuse to let you save an alias that it thinks it is too long when in fact it is not More likely however is that you will save an alias that has few enough characters for SALIAS to accept it but will become too long when the parameters are expanded And even if this does not happen you can run into trouble when the alias itself appears in a multiple command line expression and not yet executed commands have to be appended to the alias script These subtleties aside having the display of free characters is helpful To summarize in my opinion SALIAS makes all previous alias editors obsolete You should be sure to pick it up from your local neighborhood Z Node If you do not have one then join NAOG ZSIG and order a disk from them VLU Visual Library Utility VLU is a utility we have all been wishing for a screen oriented library management utility Its author is Mich
147. revent our label file from being inverten tly copied by utilities like AC or ACOPY that have the option to copy files if they don t have the ARCHIVE bit in the filename set we will also make it an AR CHIVED file In Listing 4 you will see that this involves adding 080H to the proper filename character in each case The Computer Journal Issue 30 Listing 3 Continued MREAD PAGESEL we LO ADD LO CALL LDIR LO OUT LO EX LO LO LOIR XOR RET 55265 53 g LO og e85 555555555 1X 00 1X SP SP MSTACK PAGESEL A ZBANK MOPORT A HL DMAADR DE HL HL MOBUF BC 128 A ERFLAG A SP 1X 1X 00 1X SP SP MSTACK BC 128 DE MOBUF HL DMAADR PAGESEL DE HL A ZBANK MDPORT A A ERFLAG A SP 1X HL SEKTRK A SEKSEC wee ee we we we we we wee we ve we we we we Nee we We we we we we we ve Se we Ve wi we We we We ve We ws We Ve Ve we We we Ve we Load IX with O Add SP and IX to save SP in IX local stack area Select the correct bank of memory Move it return to CP M bank Point to destination of data Point to source of data 128 bytes of data to move Move it Zero to accum No errors Restore SP to entry value Done Load iX with 0 Add SP and IX to save SP in IX Local stack area Similar to read except backwards use of buffers Move it Move it Zero to accum No errors Restore to entry value Done 1 2 32k page
148. rmatted disk If you run ZRDOS you can install it at this point Before you boot your new system run CONFIG COM to copy your current system configuration information from your current system disk to your new MDISK system disk Your Working MDISK System If all has gone well you should now have a new system disk that will boot an operating system with MDISK as drive F You can now run SYSGEN to copy the operating system to drive F and the AMPRO SWAP utility to swap drives The Computer Journal issue 30 Listing 4 Continued MOENTRY DEFB 00 User 0 DEFB MDISK File name DEFB MO SK YERS 10 0 Version number OEFB MDISKS VERS MOD 10 0 gt OEFB R 080H A M O080H Extension with R O ARC flags OEFB 00 00 00 Bit map DEF8 00 00 00 DEFB 00 00 DEFB 00 00 00 00 DEFB 00 00 00 00 3 DEFB 00 00 00 00 CPMBOOT Normal CP M boot sequence 5 End of modiftied inserted code Sssesssssssssssssszsssssessz s Listing 5 SCS1 1D FOUND DB x ENDIF IF HARD DISK AND ARBITRATION DB CR LF Arbitration Enabled ENDIF IF HARD DISK AND NOT ARBITRATION D8 CR LF Arbitration Disabled ENDIF j 332333222 Insert modified code as shown below Sisescssssssssssasasszs OEFB CR LF MDISK vers H DEFB MDI SK VERS 10 0 DEFB MDISKSVERS MOD 10 0 DEFB Enabled z2 2 2 End of modified Inserted code s ss2sssa sss2s s s ss22222 we we we Listing 6
149. ry or library We re not finished yet JetFind also supports full input out put redirection The output text that is shown on the screen can additionally be saved to a file either in a new file or appended to an existing file The set of patterns to search for can also come from a file Thus we could have the command JETFIND WN lt ASM LABEL EXP ZF Z80 gt LABELS LST This would search through all the ZFILER source code ZF Z80 for the regular expressions contained in the file LABEL EXP in directory ASM The search would require whole word matches W and include line numbers with the matching lines C N The output would be displayed on the screen and written to a new file called LABELS LST in the current directory One final comment JetFind does its work at incredible speed Bridger Mitchell is an absolute master at wringing perfor mance out of the operating system using all kinds of tricks to speed up file operations Hence the Jet in the name JetFind is available from Echelon or Echelon dealers for just 49 New ZSIG Programs Now I would like to turn to some exciting new ZSIG programs that have been released or are under development at this time LLDR Library Loader Paul Pomerleau already well known to the community as the author of such widely used programs as VERROR visual error handler BALIAS an alias editor AFIND alias finder The Computer Journal Issue 30 and the commercial LZED
150. s VALIAS accepts multiple commands and creates an ALIAS which will execute those com mands when run with a part of the VALIAS display shown below assumes that the desired utility file already exists SETUP files have had the file attribute F2 68000 SINGLE BOARD COMPUTER 395 00 32 bit Features 8bit Price Hardware features 8MHZ 68000 CPU 1770 Floppy Controller 2 Serial Perts 68681 General Puroose Timer Centronics Printer Port 128K RAM expandable to 512K on board Expansion Bus 5 75 x 8 0 Inches Software Included Mounts to Side of Drive K OS ONE the 68000 Operating 5v 2A 12 for RS 232 System source code included Power Connector same as Command Processor w source disk drive Data and File Compatible with MS DOS Add a terminal disk drive A 68000 Assembler and power and you will have An HTPL Compiler a powerful 68000 system A Line Editor 395 00 r x t x x x x x x x k r x K OS ONE 68000 OPERATING SYSTEM For your existing 68000 hardware you can get the K OS ONE Operating System package for only 50 00 K OS ONE is a powerful pliable single user operating system with source code provided for operating system and command processor It allows you to read and write MS DOS format diskettes with your 68000 system The package also contains an Assembler an HTPL high level language Compiler a Line Editor and manual 50 00 x x x k x x 2 ASS
151. s one dedicated to reading and one dedicated to writing provided the best trade off between thrashing and space One way to increase performance is to maximize the overlap ping of the input output with program execution For a write if the file already exists a preread of a sector will be required if the sector containing the record is not already in memory Rather than wait for this preread a third holding buffer of 128 bytes stores the write record while the sector preread occurs This per mits the system to copy a record into the holding buffer start the preread and return to the calling program When the interrupt signals the completion of the sector preread the holding buffer is copied into the write buffer The holding buffer protects the data The calling program may start to change it before the preread is completed Predictive Read Ahead When a program requests a disk read the system cannot return to the calling program until the read is completed Thus if the data is not in a disk buffer the program must wait until the disk access is complete If it is possible to predict what sector will be required next then the read could be started before the calling program requests it This allows disk accesses and processing to overlap and raises the throughput The problem is how to predict the next required sector CP M s file allocation structure does not force contiguous file allocation An allocation unit contains four sectors
152. s covered important and valuable material For next time however I expect to return to a more detailed technical discussion In the past few weeks I took up the task of rewriting and expanding ZEX the ZCPR3 in The Computer Journal Issue 30 memory batch execution utility This has been my first detailed look at a program of this type a resident system extension RSX a program that takes over and replaces functions of the operating system in this case the BIOS I have learned a great deal and have made what I think are some spectacular im provements to the way ZEX works and additions to what it can do Next time I will share with you what I have been doing and what I have learned E Z Systems Computer Festival December 5 1987 The Connecicut CP M Users Group will present its first Z Systems Computer Festival at Mather Hall Trinity College in Hartford Connecticut from 1 to 6 p m on December 5 Featured speaker will be noted author Jay Sage who will speak on the uses and future of the ZCPR operating system for CP M computers There will also be workshops on Z System Public Domain and Free Software and demonstrations of state of the art CP M computer hardware and software Admission is free and open to the public For further information contact Lee Bradley President Connecticut CP M Users Group 203 666 3139 CALENDAR CLOCK 69 xr NOW wit D H FIL ATE STAMPI N c Works with any Z 80 based compu
153. s for more information on ZCPR3 IOP s ECHELON INC 885 N San Antonio Road Los Altos CA 94022 415 948 3820 Echelon publishes a booklet called ZCPR3 and IOPs by Richard Conn 9 95 It is a 50 page loose leaf bound manual which explains BIOS implementation of IOP support This manual is a MUST for anyone seriously considering writing their own IOP s or customizing their BIOS It is also a MUST for anyone serious about understanding OP s Source for BIOS ASM for the Little Board Ampro Computers 67 East Evelyn Ave Mountain View CA 94041 415 962 0230 Ampro Computers offers a product identified as 1AS which is called Z80 BIOS and UTILITIES Source Code I have a fairly old price list from 1985 which shows this product s cost as 79 00 It includes the BIOS ASM file as well as the assembly language listings of all the Ampro Little Board Utilities Registered Trademarks ZCPR3 I OR B Printer Z System NuKey Echelon Little Board Ampro Computers CP M DDT Digital Research Z80 Zilog H89 H19 H29 Heath Zenith W The Computer Journal Issue 30 Reliable Cost Effective Solutions for Computerization from 329 329 1 59 Qty 100 252 Qty 100 252 Qty 100 124 A Motherboard and 4 Expansion Cards in the Space of a Half Height 5 1 4 Disk Drive J Warts 5 VOLT ONLY OPERATION aa 12 y GENERATED ON BOARD 1 SCSI BUS OPTION LARD DASK ETC ZT RSRIRC SERI
154. s second edition includes information on the 68010 and 68020 The contents are as follows Section I Fundamental Concepts Introduction to Assembly Language Programming Assemblers MC68000 Machine Architec ture Section II Introductory Problems Beginning Programs Simple Program Loops Character Coded Data Code Conversion Arithmetic Problems Tables and Lists f Section III Advanced Topics Parameter Passing Techniques Subroutines Advanced MC68020 Ad dressing and Instructions Connecting to Peripherals Exception Processing In terrupts and Other Exceptions Section IV Software Development Problem Definition Program Design Documentation Debugging Testing Section V MC68000 Instruction Set Descriptions of Individual MC68000 Instructions Section VI Appendices Alphabetic Listings of Instructions Numeric Listings of Instructions If I were limited to one book on the 68000 this one would be my choice because I can sit down with it and an assembler and work my way thru the many examples As they say on page 53 The only way to learn assembly language is to work with it A very small sample of The Computer Journal Issue 30 the example problems are byte disassem bly table lookup word assembly nor malize a binary number replace leading zeros with blanks pattern match hexadecimal to ASCII decimal to seven segment BCD to binary binary number to ASCII stri
155. s seek operation has been completed When an interrupt occurs the floppy disk controller is in terrogated and the reason is determined The appropriate subroutine is then called to handle the interrupt After every interrupt all status flags are checked for any pending tasks that need to be initiated The steps the foreground program executes are Step 1 Get the floppy disk controller status bytes to determine the reason for the interrupt If the reason is the suc cessful completion of a read or write command clear the retry flag and the read or write flag as appropriate If the reason is the unsuccessful completion of a read or write command set the retry flag Step 2 If a drive has just become ready set the recalibrate flag start the recalibrate operation and go to step 10 Step 3 If a drive has just become not ready mark any buf fers containing that drive s data as empty and go to step 10 e Step 4 Check for the recalibrate flag If so reset the recalibrate flag set density check flag start density check and go to step 10 Step 5 Check for the density check flag If so clear the flag save the density check result and go to step 10 Step 6 Check for the retry flag If so step the drive send the command to the floppy disk controller again and go to step 10 The Computer Journal Issue 30 e Step 7 Check for the read flag If so start the read operation and go to step 10 Step 8 C
156. seful work for the floppy disk controller to perform the com mand string is sent to the controller and the task starts While the controller completes the task the background program continues execution Since several foreground tasks might be invoked by one in terrupt there is a prioritized foreground queue of fixed length Since the maximum number of items in the queue three is known a priori it is not possible for the queue to overflow The three tasks are preread sector copy holding buffer to write buffer and write sector Other tasks in the queue but not at the same time include recalibrate drive check density retry last read write and read sector The queue server is very simple it only checks a set of flags to decide which tasks to invoke Foreground background communication is accomplished via a set of flags located in memory see Table 3 My system uses a Z80 and fortunately the Z80 has atomic bit set and reset instruc tions without these instructions the critical section problems would have to be solved differently When a background task needs a disk operation performed it just sets the appropriate flags and uses the floppy disk controller to generate an interrupt The foreground finds the flags set and performs each operation As an operation is complete the floppy disk controller generates another interrupt and the foreground routine clears the flag thus informing the background that the operation is complete
157. set start the foreground task by initiating a seek to the desired track e Step 10 Restore stack and exit to caller Table A Summary of Some Basic CPM Data Units unit Description The basic disk input output unit that al CPM programs use Always 128 bytes the size was determined by the creators of CPM Record The amount of data that Is always transferred between memory and the floppy disk The size Is determined by hardware considerations On a single density system the size is usually 128 bytes On a double density system the size can be anything from 256 bytes to 16K bytes always a power of 2 Allocation The minimum amount of data that can be assigned or unit given to a file The size is determined by the disk capacity and the size of the directory On a single density system usually IK On a double density system usually a multiple of 2K Directory Entry The space consumed by one entry in the directory Always 32 bytes If a file has more allocation units than will fit in one directory entry table then another directory entry is assigned to that file Four directory entries tit in one record assigned to the directory Directory Always a sixteen byte field inside a directory Entry entry it contains the allocation units assigned Allocation to the file that owns the directory entry If the Table maximum allocation unit number is less than 256 the table contains 16 entries greater than 255 and the tabl
158. t uses the wrong sector and track numbers It thinks there are 26 records per track when there really are 72 records per track This problem appears to have no solution other than to perform a software reset Control C warm boot of the system The bottom line is if CP M thinks it knows what density disk is in the drive then CP M had better be right Results and Conclusions Operating System Size The total space consumed by the operating system grew from 7K to IOK an increase of 3K or a 43 increase The bulk of the increase was due to the addition of the two 1024 byte disk buffers Floppy Disk Storage Capacity The space available for file storage on one floppy grew from 241K to 680k or 182 This disk format is a non standard format but interchangeability is not an issue If a floppy disk needs to be interchanged with another CP M system the single density format is used The single den sity format is an internationally recognized standard that every eight inch disk system must support Fragmentation The nature of the CP M directory system results in fragmentation or wasted space Because the size of the allocation unit increased from 1K to 4K increased fragmentation would be expected This conclusion was substantiated by actual measurements A single density disk containing 31 files required 189K of space When this disk was converted to a double density disk the space allocated increased to 256K due entirely to fragmentatio
159. tem for TCJ Subscribers by Richard Jacobson SSS a a TT a tS TR I TRI IETS Lillipute Z Node is the new Remote Access System RAS for The Computer Journal This arrangement had its birth a little over a month ago when Art Carlson told me he could no longer run the TCJ RAS in Kalispell Montana because of difficulties with the rural phone lines At the time I was on vacation in An chor Bay California population three hundred and fifty and couldn t really tell if the crackle was coming from Art s end or mine It occurred to me that Lillipute Z Node has been blessed with a fine central location in Chicago So I suggested to Art that we open a TCJ directory on Lillipute and give TCJ subscribers access to the new area plus three others already open to NAOG ZSIG members Art thought it was a great idea With a little bit of luck the TCJ area should be up and running by the time you read this and TCJ subscribers will have access to four directories on each of the two computers that run Lillipute Z Node Lillipute Z Node is a dial up computer system a 144 megabyte database for sophisticated users of the Z System and CP M It runs on two Ampro Little Board Plus computers Each Ampro is housed in an Integrand cabinet along with a 96 TPI floppy disk drive a 48 TPI floppy disk drive and a 72 meg full height hard drive The computers are hooked up to a pair of U S Robotics Courier 2400 modems The operating system consists of ZCPR33 ZRDOS
160. ter Currently being used in Ampro Kaypro 2 4 amp 10 Morrow Northstar Osborne Xerox Zorba and many other computers Piggybacks in Z80 socket Uses National MM58167 clock chip as featured in May 82 Byte Battery backup keeps time with CPU power off e Optional software is available for file date stamping screen time displays etc e Specify computer type when ordering e Packages available Fully assembled and tested 99 Complete kit 69 Bare board and software 29 UPS ground shipping 3 MASTERCARD VISA PERSONAL CHECKS MONEY ORDERS C 0 D s ACCEPTED N Y STATE RESIDENTS ADD 8 SALES TAX aioe wee KENMORE COMPUTER TECHNOLOGIES P O Box 635 Kenmore New York 14217 716 877 0617 25 32000 Hacker s Language by Neil R Koozer Here s a follow up to my previous comments alluding to my 32HL system 32000 Hacker s Language Before getting down to the details of what I m up to we must consider why we want to use one of the fatter processors If we re after speed we may gain enough by fixing our Z80 software For example my Z80 to 32000 cross assembler performs 51 fifty one times as fast as the commercial version from 2500AD But how fast can the 32016 do the same task if I use high quality 32000 programming The an swer is the same speed as the Z80 if we assume equal clock speeds and disallow in memory source code My previously stated goal was to break the chicken an
161. text substitution facility like define in C I ve always been mystified by the fact that some high level languages don t have certain high level features that are included in the most primative of assemblers Until just recently BASIC did not allow symbols for branch or call addresses and C does not have symbolic constants that assemblers and other languages have Text substitution is a perverse way to simulate symbolic constants because of the huge time penalty I was also shocked when i learned that C did not check the parameter list of the fun ction definition when compiling a call to a function In my first kludgy experiment in compilation of functions I would not have dreamed of neglecting this kind of checking Of course you would have to draw and quarter me to make me do run time checking Here s a summary of the current state of 32HL It s a com plete native assembler and assembles itself in one pass It calls Z80 CP M to get source text from a CP M file It has its own com mand loop and executes statements assembly or otherwise that are typed at the keyboard It has character string and numeric I O routines that are callable by client programs I now have the disassembler integrated and STOP CONT implemented but not breakpoints or the high level words The transcendentals and complex transcendentals are written and waiting to be installed I m now blacksmithing the expression parser to fit the new en vironment When
162. the first individual to use it for such a large project due to the kindness of Dave McCord and Echelon Inc in providing me with an advance copy If you are interested this might be a good subject for an article Keep up the good work S H Editor I keep looking at my Apple II for interfacing because it is so easy and cheap to get the interface cards How many others are still using Apple Ils and are you interested in an article on using them for interfacing to controllers CP M User I really like your magazine I have an Ampro Little Board Plus with a 20 Mb hard drive and Z System ZCRP3 3 ZR DOS Naturally I would like to see more High Performance Enhanced CP M articles and also software upgrades if there ever are any coverage of Z280 and HD64180 systems These are powerful machines and with Z System they do things that IBM still cannot do If you are planning to go PC just send my check back I am not that desperate yet L C Editor The great news regarding CP M software upgrades is that MicorPro has released the CP M Version of WordStar which we are using to write and edit this issue It s a tremendous improvement and all CP M users should support their effort An Open Reply to Jerry Nelson It was very refreshing to read Jerry Nelson s open letter in TCJ issue 28 His view of the world as a person who simply wants to get a job done comes as a breath of cold clean air to us and I hope
163. the state of an HTPL routine In this context only the parameter stack pointer and the return stack pointers need to be saved The routine takes two parameters First is a pointer to a place to save the old task parameter pointer and return pointer Second is a pointer to a place to get the parameter stack and return pointer for the new task The SWAPTSK routine returns to the routine that called it This leaves the return address of the routine that called NEXT as the return address on the old return stack Because all the tasks are written together in a single HTPL program all the other registers are either the same or do not need to be saved because all computations are done on the stack Using the Muititasker Each task in the multitasking system needs to call NEXT at regular intervals to let the other tasks have some time to run Most programs have a major wait loop where they get a character or wait for time to pass If there is no wait loop then any place in the main loop of a routine will do It is also important to be aware of approximately how much time is used for each routine Try to keep the time between calls to NEXT short and uniform In many cases it is neccessary to fine tune the tasks that are running by changing where NEXT is called to get a smoother running system The check character procedure chckchr is an example of how a procedure that returns a variable number of arguments is used repeat next chckchr until If the
164. to prevent two tasks from trying to update the shared data at the same time and corrupting the data Because the task swapping routine doesn t know anything about the task that is running it must save all the registers and status Most generalized multitasking systems have the ability to start new tasks and to delete old tasks This requires sophisticated memory management to allocate and reclaim memory and makes the control tables more complex because they can change in size For many control multitask applications there is a fixed number of tasks and fixed memory allocation The number of tasks is decided when the program is written and doesn t change when it runs The Value of Non Preemptive Multitasking A nonpreemptive multitask system is one where the tasks cooperate with each other A task runs for a while long enough The Computer Journal Issue 30 to accomplish something useful but not too long and then it voluntarily gives up control of the system to the next ready task Each task is also expected to be careful and not trash areas used by the other tasks in the system If a task cannot be swapped with another task without per mission then many things become much simpler First you don t need the elaborate safeguards to prevent an update from being in terrupted because the task will not be giving up control during the update process Second you don t have to make shared routines reenterant because no other task will ente
165. to the Z environ ment and command full control of the Z features that he renews our excitement all over again NuKey is no exception The Basics NuKey is a keychanger IOP A keychanger sometimes called a keyboard redefinition program can be described as a key tran slator When the keychanger is running it places itself between 15 the keyboard data and the data s destination usually the system BIOS Without the keychanger the keyboard data is processed by the BIOS With the keychanger the keychanger intercepts the keyboard data and examines it It looks to see if it should pass this data along to the BIOS without modifying it or to translate the data into some pre determined different data Normally the characters such as the letters of the alphabet numerals and pun ctuation will not be altered But you may decide to have the keychanger translate your keyboard s special function keys into strings of characters to perform system commands For example your Fi through F6 keys could be programmed to perform the functions DIR lt ret gt LDIR lt ret gt VFILER lt ret gt VMENU lt ret gt NULU lt ret gt and EDIT lt ret gt respectively Notice that the carriage return shown as lt ret gt was also programmed into the string sent out by the function keys You could have also programmed your F1 through F4 keys to generate the control functions E X S and D for Wordstar com patible cursor movement
166. to the proper location LXI D EXPATH gt DW LOIR8O Mv A OFFH STA Z3WHL Turn the whee byte on LXI H ENV Move the environment to Lx D Z3ENV the proper location LXI B ENVEND ENV Ow LDIR8O ug H tOPENT Move the dusmy IOP ul D 10P 3 to the proper location ul B IOPLEN 2 3 also copy the 2 bytes after IOPEND De LDIRBO LXI H IOPRET Change the CBOOT vector to point woe SHLD BIOS 1 to the IOPRET table 14 ENDIF ZCPR3 init XRA A STA cDISK indicate disk 0 selected STA HSTACT STA UNACNT STA HSTSID JMP GOCPM Set host buffer Inactive Clear unalloc count Assume side zero initialize amp jump to CP M wee we we we we ee This Is the dummy IOP loaded on cold boot OPENT IP 10PEND return not laplemented aP 1OPEND 3 return not isplemented IP I10OPENO return not impiemented mP IOPEND 3 return not laplemented Ie IOPRET CONST IP IOPRET 3 3 CONIN IP I1OPRET 6 CONOUT IP IOPRET 9 LIST P IOPRET 12 PUNCH IP IOPRET 15 3 READER IP IOPRET 18 3 LISTST P 1OPEND 3 return not implemented JP IOPEND 3 Feturn not impiomontod IP IOPEND return not leplemented eP IOPOD return not laplemented Ie 1OPEND return not Iapiemented 08 Z310P 08 ous OPLEN EQU 10PENT 1OPEND EQU 10P 10PLEN XRA A this byte is at IOPEND RET LOGMSG DB CR LF LF One more minor change is to be made On the last page of the listing find the two labels RESERVE The second on
167. tory entry MOTEST LO A DE Get first byte CP HL Compare with MOISK entry JP NZ MONSETUP 3 No match fail INC DE INC HL DEC C JP Z MOSE TUP All bytes match JP MDTEST Continue test MOSETUP LD HL MOSUMSG 3 Inform user MOSUDONE LO A ZBANK Go to normal CP M OUT MDPORT A 3 pages MOSUMSGP CALL PUTS Send to screen JP CPMBOOT 3 Go to normal boot sequence MONSETUP LO DE 4000H 3 Move MDISK directory entry into LD HL MDENTRY MOISK directory area LD BC 32 3 Entry is 32 bytes tong LDIR 3 And move it LD A DELCHR Get blank directory character LD DE A 3 Store first character LD H D LD L E INC DE LD BC BLKS1Z 4 32 4 allocation blocks long LDIR 3 Move it LD HL MONSUMSG Tell operator MOISK initial JP MDSUDONE j directory is al set up MDSUMSG DEFB t MOISK directory exists CR LF 0O MONSUMSG DEFB MDISK directory cleared CR LF 0 34 To create our label file directory en try we move the directory data contained in MDENTRY to the first MDISK direc tory location When that has been com pleted the rest of the directory area is filled with the blank directory character OESH The operator is then notified that the directory has been cleared and we con tinue with the boot sequence We can now reset the system at any time as long as we don t turn the power off without danger of losing our MDISK directory data and files providing that we retain our label file in the MDISK direc tory
168. uing to use the 8080 code I admit to using it for short quick amp dirty programs because we are comfor table with it and it s past time to switch over to Z80 assemblers One of the reasons for staying with ASM is that it came free when assemblers were high priced but there are now excellent low priced Z80 assemblers such as SLR s Z80ASM plus their new linker which uses bank switched or disk based overlays and Echelon s revised ZAS These superior products are so much better than ASM that anyone doing any serious work should switch over TCJ will stress the use of Z80 code and hope that any ASM diehards out there will follow along The few 8080 and 8085 users out there will have to convert the code Can anybody suggest a public domain converter W The Computer Journal Issue 30 Feedback Reader s The Computer Joumal PO Box 1697 Kallepeil MT 59903 An Avid Reader I never write letters to magazines in any form but your editorial 29 struck a responsive chord and I thought you d be interested in the reasons why at least one of your readers bought the whole back run of TCJ as of Micro C when I first descovered it a few years ago dito Micro Systems and it relates to your editorial First I never program because I can t I can t make my Kaypro IV do anything because I don t know how I don t know any language really am just now struggling thru some basic books on CP M Wa
169. ustrial Electronics As I have previously stated I firmly believe that the employment and business opportunities of the future are in using microcomputers and embedded microprocessors in areas other than per sonal and business computers Several people have told me that 90 of the CPUs and MPUs are going into commer cial products other than computers Another report states that they expect to sell 250 million microcontrollers this year and 750 million by 1990 I see a lot of help wanted ads for people experienced in industrial type ap plications but few ads for people to work on personal or business computers For example Nyland Associates Route 2 Box 352 Nebo NC 28761 phone 704 652 1801 publishes The Nayland Letter The employment newsletter for the C software engineering and programming com munity and in a recent issue they state The greatest demand seems to be in the areas of microprocessor control systems PC to mainframe connect technology local area networking as well as other areas of computer technology Those engineers expected to receive premium compensation will be working with real time control and monitoring systems drivers compiler systems robotics diagnostics artificial intelligence manufacturing office automation systems voice and data communication systems firmware graphics desktop publishing and superconductivity Con tact Mark Tokay at Nayland for infor mation on their servic
170. ut once have established the basic interface I ll be able to use it as a starting point for other programs What we develop will not be exactly what you want and will not be suitable for widely distributed commercial programs It is custom designed to fill our needs and will be constantly revised as our needs change and as we refine the in terface structure I ll publish what we are doing along with some of our ideas and discuss some of the trade offs that should be considered as a starting point for your comments and improvements The HELL With Being Compatible I Want What I Want While I use commercial products for handling database and word processing and the usual languages assemblers and compilers almost everything else involves custom programs written for our internal use only I don t sell these programs and they are not intended for wide distribution which gives me a lot of freedom because my programs don t have to run on anyone else s system One of the things which I want to im plement on my Z80 system is the use of UNIX style pipes to pass the output from one program to the input of another program as discussed in Lacobie s article Better Software Filter Design Writing Pipeable User Friendly Programs in issue 29 I d also like to add output redirec tion which is sending output from a program to a device other than the default which is usually the console and input redirection whi
171. wants to see my old FORTH BASIC system or my half done 32HL system I can send those for 8 each on CP M SSSD 8 or on IBM 360k format the IBM format for mailing only no IBM code W Neil R Koozer Kellogg Star Route Box 125 Oakland Oregon 97462 503 459 3709 Multitasking Continued from page 38 can be edited and reassembled with a larger queue At 9600 baud 960 characters can be sent each second At low baud rates fewer can be sent Send small groups of characters so that the rate of sending will not exceed the rate of the hardware causing a wait from the system A second common control action is for the program to do specific actions at regular time intervals These actions might be taking a reading or creating some kind of a log record The get time command gets the elapsed time from when the system star ted The number has no meaning per se but elapsed time can be measured by comparing the results of two different calls Another way is to use a software timer with a flag and check the flag to see if the correct amount of time has elapsed The routines presented here can be used as a Starting point for multitasking process applications They can help simplify what might otherwise have been a complex or unsovable problem Even though the examples given use HTPL and K OS ONE it is possible to use the same techniques with other operating systems or for dedicated systems that don t have an operating system in stalled Als
172. work but the SAE Vehicular Net works for Multiplexing and Data Com munications and the Truck and Bus Con trol and Communications Network sub TURBO Paacal IBM PC w ecseeee 67250 Pournelle BYTE TURBO Pascal Z2 80 cecceceeses 45 00 CP M 2 2 caccccccccoccsecccnsess 45 00 CP M 3 cccccccvccccccccvcccscees 15200 A fast aseembler is included freel I have seen the original source and youre is much better Anonymous QOG VI The following are general purpose disagsseublers __ Masterful Dieassembler 2 80 45 00 ___ UNREL relocatable files 8080 45 00 committees are both working on VLSA MC check Shipping Handling 1 50 8 specifications the markets opened by satel I mae the use of high speed data buses in vehicles will increase the need for people All products are fully guaranteed Disk format 8 Fa with real time control and munications experience Some of the experience requirements in com CP M and TURBO Pascal are trademarks of Digital Research amp Borland Int L om The Computer Journal Issue 30 3 It is easy to say that software should facilitate use by the novice without getting in the way of the expert but deciding exactly what steps need to be taken in r der to accomplish this is more difficult than it first appears even for short trivial programs I m spending much more time designing the interface than I am on the program itself b
173. would have told him the same thing impossible You know the old marines saying the dif ficult we do immediately the impossible takes a little longer Well Joe didn t even take very long to do the impossible In a matter of weeks he had a fully working version ZCOM had two drawbacks compared to a manually installed Z System First it required an extra 0 5K of overhead Secondly and ultimately more seriously it was not flexible One had to ac cept a standard configuration There was no choice of command processor options number of named directories size of RCP and so on Thus ZCOM was the Z System of choice only when a manual system could not be made either for lack of skill or lack of BIOS source code Since the new computer I bought at work in 1984 a WaveMate Bullet to my chagrin did not come with source for the BIOS I tried briefly to figure out how to get ZCPR3 installed without BIOS modifications I came up with an approach that might have worked but before I got very far with its develop ment Echelon announced Z3 DOT COM and shortly thereafter ZCOM I bought them right away After a short time I figured out how they worked and was amazed at Joe s cleverness Then I began to implement the modifications I described in my last two columns including ways to switch between different auto install systems from within alias scripts and while inside shells Later after I became acquainted with Joe I told him about
174. y Summing this all up before my battery dies I am writing this 15 miles from any power on my Z171 is that few people un derstand the need for education In studying how school systems work I can now see how little we as a nation consider education in anything we do School children are typically taught less than they really need every day in America and then our businesses continue on by asking untrained workers to do jobs requiring high skill levels For me to make a living in training our country and our business leaders will first need to become trained before they start appreciating training Over the years I have seen how important training is and yet our businesses are down playing it more and more all the time The Computer Journal issue 30 Well at least there is one place you can still get good training on how to do things and that is The Computer Journal Hopefully next time around I will start with some training on how to bring up 68K HTPL So till next month keep on computing that is if the batteries hold out long enough W Registered Trademarks It is easy to get in the habit of using company trademarks as generic terms but these registered trademarks are the property of the respective com panies It is important to acknowledge these trademarks as their property to avoid their losing the rights and the term becoming public property The following frequently used marks are acknowledged and we apologize fo
175. y allocated unit If this is done correctly unnecessary sector prereads will be eliminated Remember the write type parameter passed by the BDOS to the write routine A 4K allocation unit contains 32 records It is only on the first write to the first record of this unit that the BDOS will flag the write as a type 2 write first write to new unit All other 31 writes will be flagged as type O writes It is entirely the responsibility of the BIOS to remember this is still a newly allocated unit Remember blocking deblocking is the job of the BIOS if writes are not deferred then sector prereads could very well be required This is the algorithm used Save the write type parameter sent when the allocation unit number changes On subsequent writes to the same unit if the record number is one greater than the previous record leave the saved parameter alone When the next write record number is not exactly one greater but is in the same allocation unit the saved write type parameter is reset to type 0 This way if the first write is unallocated it will stay so as long as possible The test for an unallocated write is a 2 in the saved write type parameter rather than the currently passed value The Read Algorithm The processing of a read request is fairly straightforward when compared to a write request The steps in the algorithm are as follows gt Step 1 Switch to a local stack There is no way of knowing how much stack space is availa
176. y say that the default values worked just fine on my Heath H19 and H29 terminals In Conclusion Many Ampro Little Board computer owners have ap proached me with their dilemma of the BIOS not supporting IOP segments Some have purchased one or more of the three Echelon IOP products only to find out that they can not be run on their systems With the information provided in this article a person experienced in assembly language programming and BIOS in tegration MOVCPM SYSGEN DDT etc should have no trouble implementing IOP support for their Ampro BIOS The required source code to the BIOS is is available from Ampro Computers for a modest charge Users Group Over 115 volumes of Public Domain C source code including editors compilers communication packages text formatters UNIX like tools etc available in over 100 formats 10 NEW CUG Directory of Public Domain C source code 200 pages of file by file descriptions and index Write or call for more details f The C Users Group Box97 McPherson KS 67460 316 241 1065 17 ey Z Best Sellers Z80 Turbo Modula 2 1 disk 89 95 The best high level language development system for your Z80 compatible computer Created by a famous language developer High pertormance with many advanced features includes editor compiler linker 552 page manual and more Z COM 5 disks 119 00 Easy auto installation complete Z System for virtually any Z
177. you re in a giving mood don t forget to send along those special programs or subroutines that you worked so hard to develop When space permits I will run the source code of the shorter ones as a part of this column but will offer all of them on disk more on that subject in the next column If you still aren t moved to write do it as a favor to me just to impress my editor After all I m the new kid on the block and need all the help I can get Don t Fence Me In There are of course some guidelines that I must follow when deciding what material to work with The border of my columnistic territory is the world of CP M compatible 8 bit machines Rather than limiting the editorial content of this column to just the highly technical issues surrounding CP M I hope to give equal time to new products as well Many companies mainly the smaller one and two programmer shops continue to produce an amazing assortment of new software packages But again the direction I take will be based on your guidance So let me hear from you In the Queue I always have a seemingly endless list of projects in one state of completion or another Mine is a problem of priority not one of too little to do Nonetheless as they are finished I will make The Computer Journal Issue 30 the source code if any available on disk and space permitting run the listings here as well The projects that I am currently involved with include both hardware and

tcj_30 1987-06

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