87-01150-10rB Sysgen SC5500 Tape Controller Interface
Contents
1. Name Address Function CONTROL 292 hex Control signals Bit map PET PED Te DMAENO PCDMA3 enable active high ENTPWRCNTR Tape write counter enable active high FILEMARKEN File mark enable active high WRITE Write enable active high DMAEN PCDMA enable active high TPRDGATE Tape read gate active high TPRDSQEN Tape read sequencer enable active high ENTPINTF Tape interface enable active high MODE 293 hex Mode register interrupt enable Bit map PEBREEDT INTEN Interrupt enable active high TPDIAG Diagnostic mode active high DUAL SINGLE Active how sets single step mode active high sets dual step mode MODE Reserved for future application switching DMARQ selection to PC CSELSSCLK Single step clock enable active low enables single step clock disable TPCLK CNTSEL Drive select active low selects l0 mb drive active high selects 20 45 mb drive RESERVED RESERVED Denotes active low level 1 4 Single step mode permits only one DMA operation dual step mode permits two concurrent operations COPYRIGHT C SYSGEN INC 1985 Tape Controller Board Table 1 2 Read Registers Name Address RDTPINTF 290 hex UTH LTH CIN USF RDTPST 293 hex Bit map BREDDER TPWDA TPERRFLG TPRDXFDONE FILEMARK CARCHANGE INT DRQ DRQO XDenotes active low level COPYRIGHT C SYSGEN INC 1985 Function Read tape interface Upper tape hole Lower tape hole Cartr2. CALL _initemd call routine ADD Sp 2 remove parameter from stack result returned in AX _WAITCMD This call waits for an ERROR to occur or for the command in progress to terminate before returning control to the caller If an ERROR is returned the user should send a Request Sense command to determine the nature of the error Request Sense is described under Command Description in this chapter 2 4 7 COPYRIGHT C SYSGEN INC 1985 Software Interface C Language Protocol The C language NEAR CALL protocol is as follows status waitcmd where status is an integer for ERROR and anything else for OK ASSEMBLY Language Protocol ASSEMBLY language NEAR CALL protocol has the following stack arrangement Return Address Stack point Only CS DS ES SS and BP registers are unmodified Example of Assembly language usage CALL _ waitemd call routine result returned in AX _GETDAT If no ERROR condition is detected _GETDAT starts the DMA data input from tape to computer memory then returns control to the caller without waiting for the data transfer to complete The user can call _ POLLCMD to check for completion however he must terminate _GETDAT properly with _ WAITCMD whether or not he calls _POLLCMD This command returns an ERROR only when the controller is unable to continue operation In this case the user should abort the command protocol Any error in the operation will be reported by _ WAITCMD or _POL
3. DMA operation CALLING PROTOCOL All calls included in this section are Intel 8088 microprocessor NEAR CALLS For users of the LATTICE C Large Memory Model a special set of FAR CALL entry points is provided in Table 2 2 see the following section Alternate Entry Points Note that on entry to all the subroutines DS must be set to the C data segment DGROUP _INITCMD INITCMD starts the command execution and returns control to the caller immediately without waiting for a command to terminate It must be followed by a call to GETDAT _PUTDAT or _WAITCMD An _INITCMD call will only return an ERROR if the controller does not respond properly to the command initiation In this case the command protocol should be aborted since the controller cannot continue C Language Protocol The C language NEAR CALL protocol is as follows Status _ initcmd cmd_ code where cmd_ code integer specifying the command to execute status integer 1 for ERROR anything else for OK COPYRIGHT C SYSGEN INC 1985 2 3 Software Interface Specific command codes arc described under Command Description in this chapter ASSEMBLY Language Protocol The ASSEMBLY language NEAR CALL protocol has the following stack arrangement Return Address Stack point Stack point 2 Only CS DS ES SS and BP registers are unmodified Example of Assembly language usage PUSH word ptr cmd code spush parameter onto stack
4. When it receives an ERASE TAPE DATA command the SC5500 removes all data from the tape by writing an END OF DATA MARK at the beginning of the tape The data is not actually erased but the controller has no means of recovering it 2 14 COPYRIGHT C SYSGEN INC 1985 Software Inter face RETENSION TAPE 24H The tape controller retensions the tape by repositioning it to the beginning running it once to the end and then reversing it to the beginning again This operation restores even tension over the entire length of the tape Retensioning is recommended when a tape is first installed in the tape drive WRITE TAPE DATA 40H This command causes the SC5500 to write data from computer memory to tape in increments of 512 byte blocks Writing continues as long as the PUTDAT subroutine is called in succession Writing terminates when an ERROR occurs or the _ WAITCMD subroutine is called Note that PUTDAT and _ POLLCMD arc the only permissable calls prior to termination of this write modc WRITE TAPE FILE MARK 60H After receiving a WRITE TAPE FILE MARK the tape controller writes a special End of File EOF mark on the tape An EOF mark can be used to separate logically related blocks of data such as text files This enables the user to skip files with the READ TAPE FILE MARK command See the READ TAPE FILE MARK description below The user should be sure to write an EOF mark after the last block of data otherwise the last few blo
5. the jumper COPYRIGHT C SYSGEN INC 1985 1 9 Tape Controller Board Table 1 4 Jumper Functions Jumper Function W Selects PC address 290 W2 Selects PC address 2A0 W3 Selects PC address 2B0 W4 Selects PC address 2C0 W5 Selects IRQ3 See Figure l 2 to select IRQ5 Figure 1 2 Selecting IRQS Cut A trace w 1 RQ3 ZA Wa W3 TRQ5 1 10 COPYRIGHT C SYSGEN INC 1985 PROGRAMMABLE ARRAY LOGIC Tape Controller Board Table 1 5 describes the action of the Programmable Aray Logic PAL By using the combinations shown in the table you can transfer data in dual mode single mode or diagnostic mode The diagnostic mode is for internal testing only Signal WRITE ON OFF Don t care Don t care SINGLEX DUAL Don t care Don t care DUAL SINGLE Denotes default PAL COPYRIGHT C SYSGEN INC 1985 Table 1 5 PAL Action DMAENO ON ON OFF OFF DMAEN OFF OFF ON ON Transfer to PC PC PCDRQ3 PCDRQ3 PCDRQ I PCDRQ I also transfers the tape interrupt to PCINT Chapter 2 Software Interface Module EEE AAAS IAA ERA E LEER AE PEL EE L EEES The Software Interface Module described in this chapter is a highly intelligent PCDOS MSDOS relocatable object module that the user can incorporate in his system or application program to command the SYSGEN SC5500 Tape Controller The interface consists of six access subroutines that are calla
6. 2 18 Reguest Tape Block 1D aaa 2 19 COPYRIGHT C SYSGEN INC 1985 v Tape Controller Board Figure 1 1 SC5500 Tape Controller Boards SC5500 External Tape Controller Board 19 COPYRIGHT C SYSGEN INC 1985 Tape Controller Board Interface with the tape drive is by means of the SC5500 50 pin internal or external connector The internal version of this connector interfaces the control board with a tape drive mounted inside the host computer housing Pin assignments for the 50 pin connector are given in Appendix B Signal definition is dictated by the tape drive specifications REGISTERS AND NTROL LSES The SC5500 write and read registers transfer information between the host computer and the tape controller Control pulses triggered by the host computer reset tape error generate the single step clock and initiate read transfer from tape to computer Tables 1 1 and 1 2 define the write and read registers respectively Table 1 3 defines the computer triggered control pulses Table 1 1 Write Registers Name Address Function WITPINTF 290 hex Tape interface Bit map DEDE TRO Track O TR Track I TR2 Track 2 TR3 Track 3 GO Go REV Reverse EEN Erase enable WEN Write enable Denotes active low level Single step mode permits only one DMA Operation dual step mode permits two concurrent operations COPYRIGHT C SYSGEN INC 1985 1 3 Tape Controller Board Table 1 1 Write Registers Continued
7. C SYSGEN INC 1985 QIC 36 9 60 MB 600A 3MP Data Cartridge 600 ft 90 ips 3 mb min 8000 10000 GCR QIC 24 312 bytes 1 0 Amp Conforms to IBM PC XT and AT standards Conforms to IBM PC XT and AT short slot standards 50 pin 3M 3596 male connector internal or external Appendix B Interface Pin Assignments Fe NE r 7 g Table B 1 gives the SC5500 50 pin connector pin assignments for a QIC 36 cartridge tape drive interface For information about the DCAS cassette tape drive interface contact SYSGEN Incorporated oe oe All odd numbered pins are GND except 15 17 19 and 21 Table B 1 50 Pin Connector Pin Assignments Pin number Signal Pin number Signal ma GO JT 28 UTH_ JT 4 REV JT 30 LTH_ JT 6 TR3_ JT 32 Not connected JT 8 TR2_ JT 34 CIN_ JT 10 TRI_ JT 36 USF_ JT 12 TRO_ JT 38 Not connected JT 14 RST_ JT 40 WDA JT 15 JT 42 WDA JT 16 Not connected JT 17 JT 44 Not connected JT 20 Not connected JT 46 Not connected JT 22 DSO_ JT 48 WEN_ JT 24 HC TE EEN_ JT 26 RDP COPYRIGHT C SYSGEN INC 1985 B Appendix C SC5500 Error Codes Table C 1 lists the error codes returned by Request Sense Error Undefined command Escessive rewrite Tape write protected Tape not inserted Tape full Mission block detected COPYRIGHT C SYSGEN INC 1985 Code hex 20 40 4 42 43 44 Table C 1 SC5500 Error Codes Description An undefined command code was spec
8. used to determine how many blocks were processed before a given ERROR occurred Note that during a POSITION TO END OF DATA command the Block Count reflects the number of file marks encountered not the number of data blocks REQUEST STATISTICS BYTES C1H When the tape controller receives this command it sends eight bytes of statistics data to the buffer and then clears the count The statistics data accumulates until the next command is received The statistical bytes are arranged as follows Buffer 4 MSB Overrun Count LSB Overrun Count Buffer 5 MSB Underrun Count Buffer 6 LSB Underrun Count Buffer 7 Reread Count is the total number of read retries in tape read operations 2 18 COPYRIGHT C SYSGEN INC 1985 Software Interface Rewrite Count is the total number of data block rewrites in response to an ECC error in the read after write process during tape write operations Overrun Count is the total number of times transmission of data from the tape was halted because the controller did not receive a request for data from the host softwarc Underrun Count is the total number of times the tape was stopped and backed up over a blank space because the host software failed to transmit data for a prolonged period of time REQUEST TAPE BLOCK ID C2H When the tape controller receives this command it sends to the buffer four bytes of Tape Block ID and the first four bytes of Block Data
9. LCMD The type of error can be determined by initiating a Request Sense command COPYRIGHT C SYSGEN INC 1985 2 5 Software Interface C Language Protocol _ GETDAT has the following C language NEAR CALL protocol status _ getdat boff bseg nbytes where boff unsigned integer with the offset portion of the data buffer address bseg unsigned integer with the segment portion of the data buffer address nbytes long integer byte count must be a multiple of 512 status integer for ERROR anything else for OK A zero value for bseg has the special meaning that the data buffer is in the segment specified by the DS register default data segment in C ASSEMBLY Language Protocol The ASSEMBLY language NEAR CALL protocol has the following stack arrangement Buffer Offset MICA Stack point Stack point 2 Stack point 4 Stack point 6 Stack point 8 Only CS DS ES SS and BP registers are unmodified 2 6 COPYRIGHT C SYSGEN INC 1985 Example of Assembly language usage PUSH PUSH MOV PUSH MOV PUSH CALL ADD Note word ptr nbytes 2 word ptr nbytes 0 ax seg buffer ax ax offset buffer ax _getdat sp 8 Software Interface smsw of byte count sIsw of byte count ssegment of data buffer soffset of data buffer scall routine sremove parameters from stack result returned in AX If the cmd_ code specified to the previous INITCMD is either a Reque
10. SYSGEN SC5500 TAPE CONTROLLER INTERFACE Applications Manual SYSGEN Inc 47853 Warm Springs Blvd Fremont CA 94539 Phone 415 490 6770 Telex 4990843 87 01150 01 Rev B November 1985 Copyright notice Manual Copyright C 1985 SYSGEN Inc All Rights Reserved Printed in U S A SYSGENIM is a trademark of SYSGEN Inc IBM is a registered trademark of International Business Machines Corporation SYSGEN Inc reserves the right to make changes or improvements to the equipment software and documentation described herein at any time and without notice Every possible effort was made to ensure accuracy in this manual However SYSGEN Inc cannot accept responsibility for any manual errors or consequences resulting from such errors Unless you receive written permission from SYSGEN Inc you may not reproduce or transmit any part of this document in any form by any electronic or mechanical means including photocopying and recording or by any information storage and retrieval system How to Use This Manual EEE ERA ERE ELE ELE E This manual describes the features and operation of the SYSGEN SC5500 Tape Controller Interface for IBM PC XT AT and compatible computers The interface consists of the SC5500 Tape Controller board and the Software Interface Module containing the SC5500 control commands The interface module gives the user complete command of tape operations from his system or application program T
11. ables PCDRQ3 for a write operation and DMAENI high enables PCDRQI for a read operation COPYRIGHT C SYSGEN INC 1985 a Tape Controller Board Read transfer done is indicated by an active low latched signal on the tape read transfer done line TPRDXFDONE of the status register and also by an active high signal on the interrupt enable line INTEN of the mode register To use the interrupt line to indicate the read done you must enable INTEN active high Any error condition during read is also indicated on the interrupt line Reset pulse RSTERR triggered by the host computer will clear this interrupt WRITE OPERATION The write operation is accomplished in the following steps Refer to Tables 1 1 and 1 2 l Set the mode register MODE active high 2 Set the tape interface register WTTPINTF active low 3 Set the control register CONTROL active low a Enable the DMA DMAENO and DMAENI active high b Enable the tape interface ENTPINTF active high c Enable the write signal WRITE active high d Enable the tape write counter signal ENTPWRCNTR active high In single step mode single operation DMAENO high enables PC DMA signal PCDRQ3 for a read write or read after write operation In dual step mode two concurrent operations DMAENO high enables PCDRQ3 for a write operation and DMAENI high enables PCDRQ for a read operation The write done is indicated by an active high signal on the inter
12. age NEAR CALL protocol has the following stack arrangement Buffer Offset Offset l Stack Stack Stack Stack Stack point point point point point Only CS DS ES SS and BP registers are unmodified Example of Assembly language usage Software Interface PUSH word ptr nbytes 2 PUSH word ptr nbytesl0 MOV ax seg buffer PUSH ax MOV ax offset buffer PUSH ax CALL _ putdat ADD sp 8 COPYRIGHT C SYSGEN INC 1985 smsw of byte count sIsw of byte count ssegment of data buffer soffset of data buffer scall routine sremove parameters from stack result returned in AX 2 9 Software Interface _ POLLCMD _ POLLCMD checks for completion of DMA transfer and termination of nondata transfer commands Unlike _ WAITCMD it returns control to the caller immediately to facilitate concurrent operation This call is for inspection only _ WAITCMD must be called to terminate the command properly _ WAITCMD must be called even if an ERROR is indicated by the polling C Language Protocol The C language NEAR CALL protocol is as follows Status pollemd where status is an integer 1 for ERROR 0 for not done and anything else for done ASSEMBLY Language Protocol The ASSEMBLY language NEAR CALL protocol has the following stack arrangement Stack point Only CS DS ES SS and BP registers are unmodified Example of Assembly language usage CALL __pollcmd call routine resul
13. ble with ASSEMBLY language LATTICE C and other high level languages compatible with LATTICE C Note MicrosoftR C Version 2 XX is fully compatible but not Version 3 XX Users of Version 3 should consult their user s manual to find out how to achieve compatability SUBROUTINES The Software Interface Module subroutines are summarized in Table 2 1 This table gives the sequence of execution for data and nondata commands The subroutines can be linked directly into the user s application program or incorporated into a standard DOS device driver COPYRIGHT C SYSGEN INC 1985 dl Software Interface Table 2 1 Interface Module Subroutines Subroutine Function _ DORESET Initialize controller hardware _ INITCMD Start a tape command _ GETDAT Start data transfer tape to computer memory _PUTDAT Start data transfer computer memory to tape _ POLLCMD Check for completion of DMA transfer _WAITCMD Wait for command to terminate Command execution is in two or three phases as follows Nondata transfer commands ex Rewind l _ INTTCMD 2 _WAITCMD Data input commands ex Read Tape Data l _INITCMD 2 _GETDAT 3 _ WAITCMD Data output commands ex Write Tape Data 1 _INITCMD 2 _ PUTDAT 3 _ WAITCMD 2 2 COPYRIGHT C SYSGEN INC 1985 Software Interface The subroutines _DORESET and _ POLLCMD are supplemental _DORESET initializes the controller hardware and _ POLLCMD checks for completion of the
14. cks might be unreadable READ DATA BLOCK 80H On receipt of a READ DATA BLOCK command the SC5500 reads data from the tape into computer memory in increments of 512 byte blocks Reading continues as long as the _GETDAT subroutine is called in succession Reading terminates when an ERROR occurs or the _ WAITCMD subroutine is called Note that _ GETDAT and _POLLCMD are the only permissible calls prior to termination of this Read Mode COPYRIGHT C SYSGEN INC 1985 2 15 Software Interface An EOF ERROR is sometimes generated immediately after the controller reads the last data block before a file mark However the last data block is always transferred in its entirety before the ERROR is signaled READ TAPE DATA commands received after the controller has reached EOF will generate more EOF ERROR conditions The only way to pass over a file mark is to send a READ TAPE FILE MARK command READ TAPE FILE MARK A0H A READ TAPE FILE MARK permits the tape controller to skip from file to file After receiving this command the controller skips over data blocks until it reaches the next EOF mark Then it passes over the file mark to the first block of data it encounters beginning of the next file POSITION TO EOT DATA A3H This command sends the tape controller to the last recorded block on the tape which must be an EOT File Mark Additional data may be written on the tape when the controller is at EOT This command must be s
15. ecial protocol requirements which are discussed under Calling Protocol in this chapter Table 2 3 SC5500 Commands Command DESELECT TAPE DRIVE SELECT TAPE DRIVE REWIND TAPE TO BOT ERASE TAPE DATA RETENSION TAPE WRITE TAPE DATA WRITE TAPE FILE MARK READ TAPE DATA READ TAPE FILE MARK POSITION TO EOT DATA REQUEST SENSE BYTES REQUEST STATISTICS BYTES REQUEST TAPE BLOCK ID COPYRIGHT C SYSGEN INC 1985 Address hex OOH 01H 21H 22H 24H 40H 60H 80H AQH A3H COH CIH C2H 2 13 Software Interface DESELECT TAPE DRIVE 00H After receiving this command the SC5500 Tape Controller removes the tape drive selection signal On most tape drives the drive selection light switches off When the drive has been deselected the tape controller cannot sense tape removal But it proceeds as if the tape were changed when the drive is reselected with SELECT TAPE DRIVE SELECT TAPE DRIVE 01H This command causes the SC5500 Tape Controller to activate the drive selection signal On most tape drives the drive selection indicator light switches on The tape drive must be selected before any tape operation can be performed REWIND TAPE TO BOT 21H Upon receiving this command the SC5500 Tape Controller positions the tape to the beginning BOT When a tape is inserted in the tape drive a REWIND TAPE TO BOT command must be received before any tape read or write operation can be performed ERASE TAPE DATA 22H
16. ent before a WRITE TAPE DATA or WRITE TAPE FILE MARK unless the previous command was a WRITE TAPE DATA or WRITE TAPE FILE MARK The number of File Marks encountered can be obtained from the Block Count returned by a REQUEST SENSE BYTE command To obtain the File Mark count the user must clear the Block Count to zero with a REWIND or REQUEST SENSE command before sending the POSITION TO EOT DATA command 2 16 COPYRIGHT C SYSGEN INC 1985 Software Interface REQUEST SENSE BYTES C0H The REQUEST SENSE BYTES command must be sent immediately after an ERROR occurs Upon receiving this command the SC5500 sends eight bytes of sense data to the buffer The sense data contains the error code and other information as described below Error codes are listed in Appendix D Immediately after receiving the REQUEST SENSE BYTES command the tape controller clears the error code and sets the cumulative block count to zero A REQUEST SENSE BYTES command can also be sent when no ERROR has occurred While the error code will be zero the other fields will contain valid status information The sense bytes are arranged as follows Status Bits are arranged as follows ODO Doca where Bit 7 is TAPE CHANGED no read write possible before rewind and Bits 6 to O are reserved COPYRIGHT C SYSGEN INC 1985 o 2 17 Software Interface Block Count is a cumulative count of blocks that were successfully read or written This count can be
17. from the last successfully processed tape block These eight bytes are arranged as follows LSB Block Address Buffer 3 COPYRIGHT C SYSGEN INC 1985 _ 2 19 Software Inter face The Track Address is O for the first track 1 for the second track and so on The Control Nibble is O for a Data Block and l for a File Mark or End of Data Mark The 20 bit Block Address is O for the first block on the tape 1 for the second block and so on Each block on the tape data or control block has a unique block address For control blocks File or End of Data Mark Data Byte O specifies the total number of tracks on the tape drive Data negle lisa 3 for a File Mark and a 2 for an End of Data Mark Detailed descriptions of these bytes can be found in any QIC 24 reference document 2 20 COPYRIGHT C SYSGEN INC 1985 Appendix A SC5500 Specifications Peza Eo ff SET t re The specifications given in this appendix are for operation of an industry standard QIC 36 cartridge tape drive with the SC5500 Tape Controller For information about a DCAS cassette tape drive interface contact SYSGEN Incorporated Tape Interface Tape Track Capacity Tape Used Tape Length Tape Speed Transfer Rate at Streaming Recording Density bpi Recording Density ftpi Recording Method Recording Format Tape Block Size Power Drawn from 5V Temperature Dimensions Tape Interface Connector COPYRIGHT
18. he SC5500 Tape Controller interfaces with an industry standard QIC 36 cartridge or DCAS cassette streaming tape drive The interface described in this manual is the cartridge tape drive For information about the cassette interface please contact SYSGEN Incorporated Chapter 1 discusses the features and operation of the SC5500 Tape Controller board including functions of the read write registers and the tape controller pulses jumper selections and the action of the Programmable Array Logic PAL Summary tables are included for easy reference Chapter 2 describes the SYSGEN Software Interface Module including subroutine entry points command protocols for NEAR CALLS in both ASSEMBLY and C language and control commands An alternate set of FAR CALL entry points is provided for users of the LATTICE C Large Memory Model The chapter includes reference tables on the subroutine entry points and the control commands SC5500 Tape Controller specifications pin assignments for the SC5500 50 pin tape drive interface connector and error codes are provided in the appendixes COPYRIGHT C SYSGEN INC 1985 111 Compliance with FCC Regulations This equipment generates and uses radio frequency energy and if not installed and used properly i e in strict accordance with the Owner s Manual may cause harmful interference to radio communications It has been tested and found to comply with the limits for a Class A computing device pursuant to Subpar
19. idge in Unsafe Read tape status Writing tape write data active high Tape error flag active low latched signal Tape read transfer done active low latched signal Filemark block active high latched signal Cartridge change active high Interrupt active low Internal DMA request l active high Internal DMA request 0 active high 1 5 Tape Controller Board Table 1 3 Control Pulses Address Name hex Mode Function RSTERR 29 Write Resets tape error RDSTRXF 29 Read Starts read transfer from tape to computer TPSSCLK _ 292 Read Generates single step clock when the clock enable CSELSSCLK is low Denotes active low level READ OPERATION The read operation is accomplished in the following steps Refer to Tables 1 1 through 1 3 l Set the mode register MODE active high 2 Set the tape interface register WTTPINTF active low 3 Set the control register CONTROL active low a Enable the DMA DMAENO and DMAENI active high l b Enable the tape read gate TPRDGATE active high c Enable the tape read sequencer TPRDSQEN active high d Enable the read transfer pulse RDSTRXF active low to start the read operation 1 6 COPYRIGHT C SYSGEN INC 1985 Tape Controller Board In single step mode single operation DMAENO high enables PC DMA signal PCDRQ3 for a read write or read after write operation In dual step mode two concurrent operations DMAENO high en
20. ified More than 16 retries failed in attempt to write a single data block A write operation was attempted on a read only tape Cartridge not installed Read or write operation failed because the end of tape was reached before the operation completed Operation failed because next block is missing according to sequence number of blocks being read This error can occur even in a tape positioning command Error Codes Table C 1 SC5500 Error Codes Continued Code Error hex Missing BOT EOT 45 hole detected End of data 46 EOF Mark detected 48 Parity error during 49 command Tape change dtected 4A Controller failure GB Timeout error 4C Unrecognized 4F control block C 2 Description Controller failed to detect expected BOT and EOT hole Normal end of tape reached tape is positioned for appending Next block on tape is a file mark which can be passed only with a Read Tape File Mark command Use Request Sense to determine number of data blocks actually transferred SCSI bus parity error was detected during execution of the command The operation can t be performed unitl rewind erase retention is done Controller rejected command and is in unknown state Call DORESET then rewind tape Controller found abnormal length of blank tape or did not respond within expected time in the latter case the tape changed flag will be set Note that an entirely blank tape immediately following a file mar
21. k will usually return error 46h not 4Ch Control block other than a Tape File Mark or EOT Data Mark was read Tape may have been written by a different type of controller COPYRIGHT C SYSGEN INC 1985
22. rupt enable line INTEN of the mode register 1 8 COPYRIGHT C SYSGEN INC 1985 Tape Controller Board HARD FILE MARK The hard file mark is written by enabling the FILEMARKEN signal on the Control register active high and writing the data FF hexadecimal The data FF is subsequently converted into a unique Group Code Recording GCR 00101 00101 During read operation in dual mode the GCR is decoded as a hard file mark and FILEMARKEN is enabled on the status line active high In dual mode the GCR is transferred via Channel 3 and the 1 D is transferred via Channel 0 DIAGNOSTIC OPERATION In the diagnostic mode the LSI chip gives the data AA hexidecimal for read operation only The single step clock is enabled by an active low signal on the single step clock enable line CSELSSCLK of the mode register This signal disables the TPCLK signal and stops the 110 nsec clock The TPCLK signal is re enabled when the computer triggers the TPSSCLK pulse JUMPER FUNCTIONS Jumper W1 selects PC address 290 Jumpers W2 through W4 are only used to test the four boards simultaneously Table 1 4 summarizes the jumper functions Jumper W5 currently selects IRQ3 interrupt channel 3 If you want to make the default IRQS interrupt channel 5 you must change the jumper On some versions of the board you must also cut the trace as shown in Figure 1 2 J your board does not look like figure 1 2 you do not need to cut the trace just change
23. st Sense or Request Statistics command then 8 bytes will be transferred regardless of the value of nbytes _PUTDAT If no ERROR condition is detected PUTDAT initiates DMA data output from computer memory to tape then returns control to the caller without waiting for data transfer to complete The user can cal _POLLCMD to check for completion of the data transfer however he must terminate _PUTDAT properly with _ WAITCMD whether or not he calls POLLCMD COPYRIGHT C SYSGEN INC 1985 2 7 Software Inter face This routine returns an ERROR only when the controller is unable to continue operation In this case the user should abort the command protocol If there is an error in the operation it will be reported by WAITCMD or _POLLCMD The type of error can be recovered by means of a Request Sense command C Language Protocol The C language NEAR CALL protocol for this command is as follows status putdat boff bseg nbytes where boff unsigned integer with the offset portion of the data buffer address bseg unsigned integer with the segment portion of the data buffer address nbyte long integer byte count must be a multiple of 512 status integer 1 for ERROR anything else for OK A zero value for bseg has the special meaning that the data buffer is in the segment specificd by the DS register default data segment in C 2 8 COPYRIGHT C SYSGEN INC 1985 ASSEMBLY Language Protocol The ASSEMBLY langu
24. t J or Part 15 of FCC Rules which are designed to provide reasonable protection against such interference when operated in a commercial environment Operation of this equipment in a residential area is likely to cause interference in which case the user at his own expense will be required to correct the interference Contents EEE OE EE LEPE LEE EEE ERE EE EEES CHAPTER 1 SCS500 Tape Controller Board ccccccccrccccscssscsscssssssssccsssscssssecssscsssecsssscesescoeees 1 1 Registers and Control PUSO Sato aa 1 3 Read ODE TON a re rT Pe renee Rene ee 1 6 WI OPE ION ar E A nere 1 8 Hard File Mark ii A E A oes eR 1 9 Diagnostic Operatoria E T 1 9 Jumper FUN CLIONS tio 9 Programmable Array LORIG iii ais 1 31 CHAPTER 2 Software Interface Module lados 2 1 SUD o O o 2 2 Calling Protocolar 2 3 se ISTE A lee oner A 2 3 WAITCMD rencanan ca 2 4 OTDA aa a O NESS SE nines 2 5 PUTDA T eeraa ressorten duras 2 7 O A a A E A nano oes 2 10 DORSE EEE EA T T A EEES 2 1 Alternate Entry PO 8 0 Re En pT a Rae OO eT 2 12 Command Descrip ON esanian nere renee ned nee 2 13 Deselect Tape DINO dali 2 14 Select Tape DENE tai 2 14 Rewind Tape to BOT a dai 2 14 Frase Tape Dita bas 2 14 RETRASO Tandil a 2 15 Wite Tae Did 2 15 Write ape File MAPK nine ada 2 15 Read Data Bien osse Tee eee Me ere ee An ee rt 2 15 Read Tape File MA bly elvene eder es LES 2 16 POSILION to EOT Data ae FREDEN 2 16 Reguest Sense DES ocreata dci 2 17 Request Statistics DSi a i
25. t returned in AX 2 10 COPYRIGHT C SYSGEN INC 1985 Software Interface _ DORSET _ DORSET initializes the SC5500 Tape Controller hardware It reports an error only if controller reset fails and the controller is therefore unable to continue operating C Language Protocol This command has the following C language NEAR CALL protocol status _dorset where status is an integer 1 for ERROR and anything else for OK ASSEMBLY Language Protocol Thc ASSEMBLY language NEAR CALL protocol has the following stack arrangement Return Address Only CS DS ES SS and BP registers are unmodified Stack point Example of Assembly language usage CALL _ dorset scall routine sresult returned in AX COPYRIGHT C SYSGEN INC 1985 3 2 11 Software Interface ALTERNATE ENTRY POINTS Table 2 2 lists alternate entry points so that users of the LATTICE C Large Memory Model can invoke the subroutines as FAR CALLS The corresponding NEAR CALLS are provided for reference Table 2 2 Alternate Entry Points FAR CALLS NEAR CALLS _ SLRESET DORESET _SLINITC _INITCMD _SLGETD _GETDAT _SLPUTD _PUTDAT _SLPOLLC _POLLCMD _SLWAITC WAITCMD 2 12 COPYRIGHT C SYSGEN INC 1985 COMMAND DESCRIPTION Software Interface The SC5500 Tape Controller recognizes the commands summarized in Table 2 3 The data transfer commands Tape Data Write Tape Data Request Sensc Request Statistics and Request ID have sp
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