TU58 DECtape II User's Guide
Contents
1. 1 5 TN RN 1 5 ORE pesas Foe Ub Chr EE E deca 1 5 CONFIGURATIONS jis dacs cher tendra bs asp ead dea efr ua 1 6 HARDWARE DOCUMENTATION ORDERING INFORMATION 1 7 OPERATION TU58 CA RACKMOUNT CONTROLS AND INDICATORS 2 1 bront Panels RE Mee ner MON neem reer ener du R n 2 1 Application and Removal of nemen 2 1 TU58 COMPONENTS CONTROLS AND 2 2 Application and Removal of 2 2 CARTRIDGE M 2 2 Cartndse Lod dinge s aret ue 2 2 Cartidee Unloading eee Ge cor 2 3 Keeping Track of RR RUE 2 3 Write Protect TADAUS ode 2 3 Cartridge Storage and Care 2 3 MAINTENANGE E a E EEA NERS 2 4 Head and Puck tans aii 2 4 Operator Trouble 180 lation 2 4 dar bte cori aen etti ls Mene eda 2 5 CARTRIDGE REPAIR DTP OPUS 2 5 Metal Base Cartridge Tape Rethreading Procedure 2 6 Plastic Base Cartridge Tape Rethreading Procedure sse 2 7 Preparation for Threading drei 2 8 Threading the Cartridge iieri bericex avere 2 8 Closing the2. 5 The interface cable enters the rackmount cabinet through a connector on the back panel Draw the flat interface cable forward under the module and cage and arrange it so that the connector can fit into the header without twisting the cable The red stripe is on the left and the cable goes into its connector from below 6 Dress the cable so that it is not crimped under the cage edges and line the four cage ears with the punched tabs in the cabinet bottom plate Push the cage back into the tabs until the spring catches click 42 DRIVE AND MODULE INSTALLATION DOES NOT APPLY TO RACKMOUNT Figures 4 5 and 4 6 provide the mounting dimensions for the circuit board module and drive mecha nism The drive has a 19 cm 7 5 in cable which plugs into the module header with the wires coming out of the plug toward the center of the module The plug is keyed to ensure proper orientation The cartridge extends 1 60 0 62 in from the front of the drive If the drive is recessed in a panel clearance must be provided around the opening for fingers to grip the cartridge Ideally the cartridge slot in a front panel will be somewhat larger than minimum to allow easy insertion The opening should be at least the dimensions of the cartridge 1 3 0 5 in X 8 1 cm 3 2 in located not more than 0 53 cm 0 17 in above the bottom mounting surface line A in Figure 4 8 The module should be mounted on a flat surface with 3 mm 6 32 in hardware and 1 cm
3. detachable line cord and fuses for 110 V two cartridges Additional Supplies NOTE Order interface cable separately BC20Y 25 interface cable 58 to DL 11 and DLV 11 7 5 m 25 ft 10 pin to 40 pin connector BC20Z 25 interface cable TUS8 to DLV 11J 7 5 m 25 ft 10 pin to 10 pin connector TUS8 K preformated tape cartridges Available singly or in packs of five TUC 01 Tape Drive Cleaning Kit 1 6 HARDWARE DOCUMENTATION ORDERING INFORMATION The following TUS8 DECtape II Tape Subsystem hardware manuals can be purchased from DIGITAL s Accessory and Supplies Group Part No Title EK 0TU58 UG 001 TUSS Tape Subsystem User s Guide paper EK 0TU58 PS 001 TUSS8 Tape Subsystem Pocket Service Guide card EK 0TUS58 TM 001 TUSS Tape Subsystem Technical Manual microfiche All purchase orders for hardware manuals should be forwarded to Digital Equipment Corporation Cotton Road Nashua New Hampshire 03060 Accessory and Supplies Group P086 Purchase orders must show shipping and billing addresses and state whether a partial shipment will be accepted All correspondence and invoicing inquiries should be directed to the above address or call toll free 1 800 258 1710 in the continental U S only 1 7 CHAPTER 2 OPERATION 2 4 TUS8 CA RACKMOUNT CONTROLS AND INDICATORS 2 1 1 Front Panel The front panel Figure 2 1 has two slots for the tape cartridges and two tape motion indicator lights for the drives In addition the d
4. 3 8 in standoffs Both the module and the drive may be mounted at any angle For mounting from above the drives require 1 80 cm 0 71 in clearance hole spacing is given in the outline drawings For mounting from below the drives require an 8 18 cm 3 22 in X 8 89 cm 3 50 in chassis cutout with the same mounting hole spacing CAUTION The mounting surface for the drives must be flat within 0 64 mm 0 025 in 43 INTERFACE STANDARDS SELECTION AND SETUP The TUSS is shipped with factory instalied jumpers for a transmission rate of 38 4 kilobaud and the RS 423 unbalanced line interface A variety of standards and rates may be selected by changing the jumpers on the controller module Table 4 1 provides a list of all the pins on the board and their functions including the wire wrap WW pins interface and power connectors 4 5 8 18 3 22 DEC TU58 K CARTRIDGE M A 71 1 80 isis MEASUREMENTS ARE IN 1 38 DIA CENTIMETERS EXCEPT 8 89 VALUES IN PARENTHESES 3 50 ARE IN INCHES MA 2369 Figure 4 5 Drive Outline Drawings 30 48 12 19 1 27 50 14 73 10 03 5 80 3 95 64 25 AMP HEADER 87633 6 AMP 87272 8 ALL HOLES MATE AMP 87159 6 DEC PT 12 13506 04 0 30 WITH 87027 CONTACTS MATE AMP 487133 5 12 DIA HEAT SINK WITH 87124 1 CONTACTS 3 0 1 2 ABOVE 12 98 13 18 5 11 5 19 0 5 0 2 BELOW 12 POWER GND CONNECTOR 5 DRIVE A DRIVE B SERI
5. 32 RADIAL SERIAL PROTOCOL RSP 3 2 Message Packets All communication between the TU58 and the host is divided into message packets which are groups of bytes arranged in fixed order Position within the packet determines the meaning of each byte There are three kinds of message packets command data and end messages The end message is a special case of the command packet In addition there are three single byte protocol management messages INIT Continue and XOFF 3 1 Each packet begins with a flag byte which announces its contents The next byte in a message packet is the byte count This is the number of message characters in the packet excluding the flag byte count and checksum Up to 128 message bytes may be in each packet Larger blocks of data are sent with multiple packets The last two bytes of the message packet are a l6 bit checksum The checksum is formed by summing successive byte pairs taken as 16 bit words and using an end around carry from bit 15 to 0 The flag and byte count are included in the checksum 3 2 2 Flag Byte Op Codes Bits 7 5 of the op code are reserved 00001 Data 00010 Control command 00100 INIT 10000 Continue 1001 1 XOFF Data This flag informs the receiver that data rather than commands are arriving The receiver loads the incoming bytes into a buffer area in memory It does not look for an op code to execute Command The command flag informs the TUS8 that a command packet follows
6. Carthage s eni es v due daa Lee pria eis 2 9 PROGRAMMING GENERAL PRINCIPLES 3 1 Block Number Byte Count and Drive Number esee 3 1 Special Handler Functions 3 1 iii 3 2 3 2 1 3 2 2 3 2 3 3 3 3 3 1 3 3 2 3 3 3 34 CHAPTER 4 4 1 4 1 1 4 1 2 4 1 3 4 1 4 4 2 4 3 4 3 1 4 3 2 4 4 4 4 1 4 4 2 CHAPTER 5 Figure No CONTENTS Cont Page RADIAL SERIAL PROTOCOLX RSP eye E e eus 3 1 Message PACK CUS et 3 1 Flag Byte Op Codes 3 2 Signal Break and Initialization 3 2 3 3 Command PACK CES 3 3 Data PACK CIS ol oed eti bte s npn dud 3 4 capo E RU oe bete Eo pte PER 3 5 RHE INSTRUCTION 3 6 INSTALLATION INSTALLATION OF RACK VERSION 4 1 Mounting 1nd RACKS sac e Iud d rA eodd 4 Power Selection for the Rack 101 enne 4 3 Removing Module From Chassis EN PR ae 4 3 Reinstalling the Module 4 5 DRIVE AND MODULE INSTALLATION DOES NOT APPLY TO RACKMOUNT cit ooh a fae M vedi asta de E M Rd 4 5 INTERFACE STANDARDS SELECTION AND 4 5 Selecting Interface Standards sus iecore e eb Cedo poen Uns 4 8 Connecting Standards J mpe
7. Protocol 1 3 BLOCK DIAGRAM Figure 1 3 illustrates the structure of the TU58 system The data path is along the top of the diagram passing to the host through the processor at the right The drive control is at the lower left also closely associated with the processor through the I O ports The ports memory and universal asynchronous receiver transmitter UART are tied to the processor by an 8 bit wide data address bus WRITE AND ERASE LOGIC AND DRIVERS CONTROLLER INTERFACE PORTS PROCESSOR 8085 SERVO AMP AND DRIVE SELECT DRIVERS RECEIVERS TO HOST MA 2378 Figure 1 3 TUS58 Block Diagram 1 3 1 3 1 Drive Control The cartridge drive motors are powered by servo regulated speed and direction circuits These are controlled by the processor which monitors with tachometers and with signals from the tape The heads are selected by processor controlled switches and either feed the automatic gain controlled AGC read amplifier and decoder circuits or are driven by write currents encoded by the processor 1 3 2 Processor The processor consists of an 8085 processor supported by firmware in a 2 kilobyte read only memory ROM and by scratchpad and data buffer memory in a 256 byte random access memory RAM The processor communicates with the drive control circuitry through a bidirectional I O port The UART exchanges data between the 58 processor bus and the host computer via the
8. an LED which lights to indicate tape motion Since data loss can occur if a cartridge is removed while the tape is being written the cartridge should not be touched if the light is on S 1 1 Installation The LED which may be any device capable of handling 30 mA with a forward voltage less than 1 8 V is wired in series with the tachometer source LED Splice the run LED into the wire from pin 7 of the drive connector Count from the end with the missing pin That pin is number 2 The anode should be on the module side of the wire symbol arrow pointing away from pin 7 See Figure 5 1 The LED is available from DEC as part number 11 10324 and wires with slip on connectors are available to join the LED to the track cable number 70 16526 and to extend the module connector end to the LED at the front of the drive cable number 70 16525 TO PIN 7 ia ADDED PIN 7 12V TACH PIN 8 PIN 9 MA 2385 Figure 5 1 Installation of Run Indicator 5 5 2 BOOT SWITCH Some applications use the TUS8 as a program loader The intelligence of the TU58 enables it to perform a seek and read operation without processor commands Pins are available on the controller module which when connected by the Boot switch initiate the following actions 1 On power up the TUS8 checks for the presence of the closed switch It then delays 1 second and begins the boot procedure 2 When the TUSS is in the idle state it monitors the Boot switch Any switch
9. and generate a boot tape containing that program suitable for auto matic loading The boot pin on the module WW16 may be connected to ground WW15 through a normally closed momentary action switch Paragraph 4 4 2 Wires may be wire wrapped DEC Grip Clipped or sol dered to the pins Placement of the switch and lead dress are not critical if adequate clearance is provided around moving parts of the drive and the heat sink and power resistors on the module 5 2 TUS8 DECtape Reader s Comments USER S GUIDE EK 0TU58 UG 001 Your comments and suggestions will help us in our continuous effort to improve the quality and usefulness of our publications What is your general reaction to this manual In your judgment is it complete accurate well organized well written etc Is it easy to use What features are most useful What faults or errors have you found in the manual Does this manual satisfy the need you think it was intended to satisfy Does it satisfy your needs Please send me the current copy of the Technical Documentation Catalog which contains information the remainder of DIGITAL s technical documentation Name 1 20 Street Title City Company 1 State Country Department Additional copies of this document are available from Digital Equipment Corporation 444 Whitney Street Northboro Ma 01532 Attention Communications Services NR2 M15 Customer Services Section
10. and logic steering functions in the controller The tape 15 protected by motor current limiting and an anti runaway timer Because of the intelligence requests from the host for data retrieval or storage need only contain simple specifications about the transfer The controller positions the tape and performs the transfer without supervision from the host The host and controller communicate in a format called Radial Serial Protocol RSP The RSP uses two kinds of byte sequences called message packets Both command and data packets have protocol information placed in specific locations in the byte sequence This format is easily generated by the TUSS8 making host peripheral interaction possible at a high level with low cost Figure 1 2 illustrates a typical RSP exchange between a host computer and the TU58 Refer to Chapter 3 for a full discussion of RSP implementation The serial host interface operates on full duplex asynchronous 4 wire lines at jumper selectable rates from 150 to 38 4 kilobaud The send and receive rates may be independently set with jumpers to operate in accordance with Electronic Industries Association EIA Standards RS 422 or RS 423 When set to RS 423 the TUSS8 is also compatible with devices complying with RS 232 C 1 2 HOST 1158 COMMAND PACKET CONTINUE i DATA PACKET CONTINUE i DATA PACKET END MESSAGE PACKET lt gt Q e a Figure 1 2 An Exchange in Radial Serial
11. free end insert the end between the hub and belt and operate the drive roller with a finger to take up the tape As soon as the tape is grabbed keep some back tension on the tape This will keep it feeding straight into the hub Continue to wind Watch for the loose end as it comes around If it separates from the hub tuck it under the next turn of tape with the probe Back up if the end is too long Continue to wind a few more turns with the drive roller while applying tension to the tape Hold the takeup hub and driveroller fixed and rotate the supply reel to take up the slack Continue winding the tape about 20 turns before reassembling To reassemble the cartridge reinstall the gate if desired by aligning the long and short ends of the spring with the long and short ends of the gate as in Figure 2 7 Drop the spring into the well in the gate Holding the spring down with a thumbnail or probe rotate the long end of the spring around to the slot that is at a right angle to the long dimension of the gate Push the end of the spring into the slot it should stay there by itself MA 2361 MA 2362 Figure 2 5 Metal Baseplate Screw Locations Figure 2 6 Threading the Metal Base Cartridge 2 6 MA 2358 Figure 2 7 Head Gate and Spring 12 Hold the gate halfway out so that the gate and the spring end do not touch the tape Slowly press the gate down onto its pin on the cartridge baseplate Reach in with the probe and press the
12. manuals Chapter provides a general description of the TUS8 and a list of its specifications including electrical and mechanical requirements The configurations section describes the different variations of the TUSS that are available Chapter 2 the system operator s reference section contains important information for day to day operation and routine maintenance Chapter 3 is the programmer s guide It contains functional descriptions of the TU58 command set illustrates command sequences explains the details of the Radial Serial Protocol and lists the system instruction codes and byte sequences Chapter 4 gives illustrated instructions for jumper selection mechanical electrical and interface in stallation and operational checkout of the tape system Chapter 5 has details about the optional features available in the TUS8 1 2 GENERAL DESCRIPTION The TUSS is a random access fixed length block mass storage tape system It uses preformatted tape cartridges which store 262 kilobytes of data in 512 byte blocks There are 256 blocks on each of two tracks They may be accessed by a program in a fashion similar to data stored on disks or DECtape using a new high level instruction set A file oriented structure is easily implemented in an operating system by setting aside several blocks on the tape to store a directory The TUSS8 is compact and mechanically simple The tape cartridges are DIGITAL preformatted min iature reel to
13. serial line drivers and receivers 1 4 SPECIFICATIONS 1 4 1 Performance Capacity per cartridge Data transfer rate Read write on tape Data buffer to interface Cartridge life Data reliability Soft data error rate Hard error rate Hard error rate with write verify and system correction Error checking Average access time Maximum access time Read write tape speed Search tape speed Bit density Flux reversal density Recording method Medium Track format Figures 1 4 and 1 5 Drive Drives per controller 262 144 bytes formatted in 512 blocks of 512 bytes each 41 7 us data bit 24 kbytes s 150 to 38 4 kbaud jumper selected 5000 minimum end to end tape passes in 107 bits read before self correction 1 in 10 bits read unrecoverable within 8 automatic re tries 2 in 1011 bits read written Checksum with rotation 9 3 seconds 28 seconds 76 cm s 30 in s 152 60 in s 315 bits cm 800 bits in 945 fr cm 2400 fr in Ratio encoding DECtape II cartridge with 42 7 m 140 ft of 3 81 mm 0 150 in tape Size 6 1 X 8 1 X 1 3 cm 2 4 X 32 X 0 5 in Order TU58 K NOTE DECtape II is a preformatted version of the 3M DC100A or equivalent Two tracks each containing 1024 individually num bered firmware interleaved records Firmware ma nipulates 4 records at each operation to form 512 byte blocks Single motor head integrally cast into molded chassis 1 or 2 Only one may
14. spring down It will clear its holding slot and snap into position closing the gate 13 Carefully lower the cartridge cover into place and reinstall the screws 2 5 2 Plastic Base Cartridge Tape Rethreading Procedure Open the plastic base cartridge case by prying the sides apart with a screwdriver Figure 2 8 Do not cut the label on the back of the cartridge it acts as a hinge to help hold the case together The leverage applied when spreading the case halves will break the rear welds Figure 2 9 MA 2363 Figure 2 9 Welded Case Halves Separated MA 2357 Figure 2 8 Open the Plastic Base Cartridge 2 7 2 5 2 1 Preparation for Threading The four rollers and tape hubs in the plastic base cartridge are held in their operating plane by the top and bottom of the case together When the top is off the various parts tend to creep out of position and the elastomer belt can get folded under the hubs 1 organize the parts for threading remove and discard the head gate and spring Take the empty tape hub from the case and set it aside 2 Remove the floating roller Figure 2 10 3 Rearrange the elastomer belt around the drive roller and the full hub 4 Reinstall the floating roller and use it to stretch the belt tight 5 Put the empty tape hub on its pin 6 Using some fingers to hold the floating roller and belt and other fingers to push the hub down use a straightened paper clip or pencil to guide the elastomer bel
15. to 1 Ensure that the TU58 CA is plugged into a live ac host socket or proper dc source for components 2 Check thatthe voltage selection switch is properly set Ensure that the fuse and power cord are intact and properly inserted 4 Check that the baud rates and interface standards are the same for both the TU58 and the host interface board Paragraph 4 3 5 If possible observe the self test indicator light on the controller module Remove the bezel on the rack mount version Paragraph 4 1 1 When power is ap plied the light should shine for half a second go out for another half second and then relight This means the controller has passed its automatic self test and is ready for operation If the light remains off there is some problem within the module or in the interface Check that the interface cable is intact and properly inserted If the serial interface is suspected and the standards are correct try a new interface cable open wire in the line from the host prevents the light from coming on Other causes require servicing TUSS8 does not write reads l Check that the Write Permit tab is correctly on the okay cartridge Figure 2 3 2 The trouble may be in a drive Try writing the other drive Any problem except the Write Permit tab setting requires service 2 4 Table 2 1 Operator Trouble Isolation Cont Symptom Action Comments Read errors Some host 1 Clean the head Dirt and tape ox
16. 8 3 2 22 d Inr 8 0 2 p 5 3 16 FRONT OF BEZEL REMOVED 5 19 3 65 1 438 5 24 jou oo 48 3 2 06 19 0 13 2 5 19 FRONT A 34 3 ense 13 5 1 5 EE 44 5 17 5 13 2 5 19 13 2 5 19 48 3 19 0 MA 2354 Figure 4 2 Rack Mounting the TU58 CA 4 2 4 12 Power Selection for the Rack Version A line cord for 110 V and two fuses are supplied with the TUS8 CA Line cords for other voltages and standards may be purchased separately The chassis power receptacle meets European IEC standards A switch on the back of the rackmount cabinet selects 110 or 220 V Figure 4 3 o 110 220 V SWITCH INTERFACE FUSE POST a CABLE CONNECTOR e 4 lo LINE CORD RECEPTACLE MA 2367 Figure 4 3 58 Rear Panel 1 Set the switch to the correct value using a small screwdriver CAUTION If the unit is plugged into a 220 V circuit while set for 110 V it may be severely damaged 2 Install a fuse in the fuse post NOTE 3 8 A slow blow fuse is required for 220 V 3 4 A slow blow fuse for 110 V 3 Insert the appropriate power cord into the receptacle Do not plug it into an outlet until the installation is complete 4 1 3 Removing Module From Chassis The drive and module mounting cage must be pulled forward for the module to clear the bottom of the rack cabinet Figure 4 4 1 Unplug the power drive and interface connectors CAUTION
17. 8 to read the tape with an increased threshold in the data recovery circuit This makes the tape drop bits if any weak spots are present Thus if the TUSS8 can read error free in this mode the data is healthy The read transaction between TUS8 and host is shown in Figure 3 1 HOST TU58 COMMAND PACKET READ 510 BYTES DATA 128 BYTES A DATA 128 BYTES DATA 128 BYTES DATA 126 BYTES MA 2376 Figure 3 1 Read Command Packet Exchange CODE 3 Write and Write and Read Verify This op code causes the TUSS to position tape in the selected drive to the block specified by the number in bytes 10 11 of the command packet and write data from the first data packet into that block It writes data from subsequent data packets into one or more blocks until the byte count called out in bytes 8 9 of the command packet has been satisfied The controller automatically zero fills any remaining bytes in an 512 byte tape block There is one modifier permitted with the write command modifier of 0000 0001 causes the TU58 to write all of the data and then back up and read the data just written with increased threshold and test the checksum of each record If all of the checksums are correct the TU58 sends an end packet with the success code set to 0 or 1 if retries were necessary to read the data Failure to read correct data results in a success code of 6 1111 1010 to indicate a hard read error The write operat
18. AL INTERFACE CONNECTOR 48 19 29 69 27 MEASUREMENTS ARE IN CENTIMETERS EXCEPT VALUES IN PARENTHESES ARE IN INCHES MA 2370 Figure 4 6 Module Outline Drawing 4 7 Table 4 1 TUS58 Module Connections Wire Wrap Pins WW 150 Baud WW2 300 Baud WW3 600 Baud WWA 1200 Baud WWS 2400 Baud Wwe 4800 Baud WW7 9600 Baud WWS 19200 Baud WW9 38400 Baud WWIO UART Receive Clock WWII UART Transmit Clock WWI2 Auxiliary to interface connector pin WWI13 Auxiliary B to interface connector pin A WWI4 Factory Test Point WWIS Ground WWI6 Boot Connect together for auto boot on power up WWI 7 RS 423 Driver WWI8 RS 423 Common Ground WW 19 Transmit Line WW20 Transmit Line WW2l RS 422 Driver WW 22 RS 422 Driver WW23 Receiver Series Resistor WW 24 Jump for RS 422 Serial Interface Connector J2 A Auxiliary B J2 H Transmit Line J2 B Ground J2 J Transmit Line J2 C Receive Line J2 K Ground J2 D Receive Line J2 L Auxiliary A J2 F Ground Power Input Connector 11 1 12V J1 3 Ground J1 5 5 J1 6 Ground Drive Cable J344 1 Cart L J3 4 9 LED 13 4 2 No Connection J3 4 10 Head Shield Ground J3 4 3 Permit L J3 4 11 Erase Return J3 4 4 Signal Ground J3 4 12 Erase 13 4 5 Motor J3 4 13 Erase 0 J3 4 6 Motor J3 4 14 Head Return J3 4 7 12V J3 4 15 Head 0 J3 4 8 Tachometer J3 4 16 Head 1 4 3 1 Selecting Interface Standards The serial interface
19. An instruc tion code will be in this packet The flag is particularly important when the TU58 encounters an error condition In this case it sends an end packet before data trans fer is complete The host knows that the end packet has been sent because the packet received has a command flag instead of a data flag INIT This op code is sent from the host to the TUSS8 to cause it to execute its power up sequence The TUSS returns Continue after completion It is sent from the TU58 to the host to indicate that the power up sequence has occurred When the TU58 makes a protocol error or receives an invalid command it reinitializes and sends INIT to the host The TU58 must send up to 261 INITs in this case because the host may think it is receiving a message packet and will not interpret the INIT until the mes sage packet is complete Continue After a message is sent from host to the TUS8 the host must wait until the TUS8 sends Continue before any more messages can be sent This permits the TUS8 to control the flow of data XOFF Ordinarily the TU58 does not have to wait between messages to the host However if the host is unable to receive all of a message from the peripheral at once it may send XOFF The TUS8 stops transmitting immediately and waits until the host sends Continue to complete the transfer when it is ready Two characters may be sent by the UART to the host after the TUS8 receives XOFF 3 2 3 Signal Break and Initialization S
20. Be careful around the thin tachometer disk It is eas ily bent and its edge is sharp If the disk gets bent without creasing it might be straightened with pliers Alignment is not critical but it is better if the disk does not rub against the optical sensor block It it cannot be aligned or if it is creased it must be re placed 2 Lift one of the spring metal catches at the bottom left or right edges of the cage and pull that side of the cage forward just enough to clear the catch 3 Release the other side in the same way 4 Slowly pull the cage forward about 5 cm 2 in 5 Unlatch the module handle locks and pull the module out The loose cage may be tilted to provide clearance 4 3 Figure 4 4 Module Removed from Chassis 4 4 4 1 4 Reinstalling the Module 1 Slide the module into the guides the cage lifting the drive cables out of the way This may be done with the cage removed from the rack Do not latch the module into place yet 2 Plug the drive cables into the module headers left drive to left header and right to right The plugs are keyed and install with the cables attached to them from the rear of the cabinet 3 Set the cage on the edge of the cabinet and reach behind to the power supply cable Thread the cable into the cage over the module The three keying fingers are on the left as the plug goes onto the power header on the module 4 Push the module firmly into the cage and latch it into place
21. D 5 0000 0000 NOT USED 6 0000 0000 SEQ L 7 0000 0000 NOT USED 8 0000 0000 ACTUAL BYTE CNT L 9 0000 0000 ACTUAL BYTE CNT H 10 0000 0000 SUMMARY STATUSL T XXXX XXXX SUMMARY STATUSH 12 000X XXXX CHECKSUM L 13 XXXX XXXX CHECKSUM H NO DATA INVOLVED NO POSITION NO DATA INVOLVED OP CODE 1 INIT This instruction causes the TUSS8 controller to reset itself to a ready state No tape positioning results from this operation The command packet is the same as for NOP except for the op code and the resultant change to the low order checksum byte The TUS8 sends the same end packet as for after reinitializing itself There are no modifiers to INIT CODE 2 Read and Read with Increased Threshold This instruction causes the TUSS to position tape in the drive selected by Unit No to the block designated by the block number bytes It reads data starting at the designated block and continues reading until the byte count command bytes 8 and 9 is satisfied After data has been sent the TU58 sends an end packet Byte 3 indicates success success with retries or failure of the operation In the event of failure the end packet is sent at the time of failure without filling up the data count The end packet will be recognized by the host by the flag byte The host will see a command flag 0000 0010 instead of a data flag 0000 0001 There is one modifier to the read command A modifier of 0000 0001 causes the 5
22. EK OTU58 U G 001 TU58 DECtape User s Guide digital equipment corporation maynard massachusetts Ist Edition October 1978 The drawings and specifications herein are the property of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of equipment described herein without written permission Copyright 9 1978 by Digital Equipment Corporation The material in this manual is for informational purposes and is subject to change without notice Digital Equipment Corporation assumes no re sponsibility for any errors which may appear in this manual Printed in U S A This document was set on DIGITAL s DECset 8000 computerized typesetting system The following are trademarks of Digital Equipment Corporation Maynard Massachusetts DIGITAL DECsystem 10 MASSBUS DEC DECSYSTEM 20 OMNIBUS PDP DIBOL OS 8 DECUS EDUSYSTEM RSTS UNIBUS VAX RSX VMS IAS 8 80 15 Ww hb CONTENTS Page INTRODUCTION SCOPE ist 1 1 GENERAL DESCRIPTION ainsin tiiri evo 1 1 BLOCK AT 1 3 Drive Controls topi iva da EAT 1 4 AMO MID 1 4 SPECIFICATION So MENS rue ext ossa RE eb d oca 1 4 1 4 BTS
23. Figure 4 9 Factory Wiring 4 10 4 4 OPERATIONAL CHECKOUT A confidence check of the operation of the newly installed TU58 may be performed through the console or keyboard console emulator of a host system without the use of an operating system device handler The light on the TU58 module should be on indicating a functional processor 4 4 1 Checkout of Interface To address the serial interface device registers with the console consult the system manuals for ad dresses and codes perform the following steps Set the transmit control status register to send Break to the TUS8 Remove the Break condition Transmit INIT 04 octal to the TUS8 Transmit a second 04 Examine the receive data buffer to find Continue 20 octal 4 4 2 Checkout of RSP and Command Function 1 Insert a tape cartridge into drive 0 left side 2 Transmit the following string of octal numbers to the TUS58 Consult the programming chapter for an explanation of this format Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9 Byte 10 200 Byte 11 200 Byte 12 0 Byte 13 204 Byte 14 212 lt lt The TUSS should wind to the beginning of the tape and read about half of the tape 4 11 CHAPTER 5 OPTIONS Options may be added to the 58 to enhance its product performance These additions are described in this chapter 5 1 RUN INDICATOR Each tape drive may be modified to have
24. Order No EK 0TU58 UG 001 FIRST CLASS PERMIT NO 33 MAYNARD MASS BUSINESS REPLY MAIL NO POSTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES Postage will be paid by Digital Equipment Corporation Technical Documentation Department Maynard Massachusetts 01754
25. acket with appropriate success code 0 Pass 1 Fail OP CODES Get Status This command is treated as an The TUS8 returns an end packet OP CODE 9 Set Status This command is treated as an NOP The TUSS returns an end packet OP CODE 10 Reserved OP CODE 11 Reserved 3 9 CHAPTER 4 INSTALLATION 4 1 INSTALLATION OF RACK VERSION 4 1 1 Mounting in a Rack The TU58 CA rackmount unit mounts in 13 2 cm 5 2 in of standard 48 3 cm 19 in width rack It should be located so that the 2 m 6 ft power cord can reach a power controller outlet box such as the DEC 861 or any power outlet To get to the mounting holes remove the bezel Figure 4 1 by gripping it at the top and bottom with both hands Rotate it out from the bottom and lift it away If the unit is installed in a recessed rack the bezel may be removed by gripping it with both hands on the left edge with fingers or thumbs inside the storage well Pull sharply out and swing the bezel away WARNING Early bezels are heavy MA 2382 Figure 4 1 Bezel and Clip If the rack requires them install four speednuts at the holes spaced according to Figure 4 2 The 58 is light enough for one person to install Put the two bottom screws in first to avoid bending the mounting ears FRONT VIEW TOP OF BEZEL WIDE 6 04 286 NARROW 23 8 11 8 WIDE WIDE Um BOTTOM OF BEZEL 1 11 46 5 0 438 1
26. ay from dust and heat or direct sunlight Do not touch the tape there is no safe way to clean the tape and permanent errors may result Keep tools and other ferrous or magnetic objects away If a tape is suspected of having been exposed to environmental extremes as listed in the specifications and if the software operating system permits wind it all the way through with a Newtape Paragraph 3 1 2 or equivalent command or by requesting positionings to blocks at each end of the tape before attempting to store data on the cartridge 2 3 2 4 MAINTENANCE 2 4 1 Head and Puck Cleaning After 250 hours of tape running time or semi annually clean the head and motor puck with a long handled cotton applicator moistened with DEC cleaning fluid from cleaning kit TUC 01 95 percent isopropyl alcohol fluorocarbon TF 113 or equivalent Figure 2 4 Push the puck around with the applicator to clean its entiresurface Regular cleaning minimizes tape and head wear and prevents tape damage and data errors caused by contamination This is the only regular maintenance required by the TUSS JE DRIVE PUCK TAPE HEAD MICROSWITCHES MA 2374 Figure 2 4 View Into Tape Drive Cartridge Slot 2 4 2 Operator Trouble Isolation Table 2 1 lists potential problems and possible corrective actions and comments Some items are not applicable to components Table 2 1 Operator Trouble Isolation Symptom Action Comments TU58 does not respond
27. contact open close sequence causes l second delay to allow for contact settling to allow the host processor to enter the halt mode and then the TUS8 begins the boot procedure The boot procedure positions the tape in drive 0 to block 0 sends Break to the host and transfers ASCII characters from the tape to the host in groups of seven Each group is separated from the adjacent groups by 15 character times based on 9600 baud The TUS58 exits the boot mode following the transfer of the terminating character ASCII 1474 and enters the idle state Because of the timing requirement only rates of 9600 19 2 and 38 4 kilobaud may be used with boot Boot is intended for use with the LSI 11 The boot tapecontents are formatted to appear to the LSI 11 as output from a console keyboard operating under the ODT keyboard interpreter This means that the TUS8 must be located at the standard console address the LSI 11 bus A keyboard cannot be connected at the same time This arrangement is useful in an unattended control system where the TUSS8 can automatically load and start or reload and restart an unsupervised process controller or similar application The Boot switch allows a reboot without powering down to cycle the automatic sequence NOTE Boot mode does not work in any DEC operating sys tem environment A utility program running under RT 11 will be available from DEC which will take a user program that was developed under RT 11
28. e Cartridge e seem riter o rer YU tW E Read Command Packet Exchange o aei aet Write Command Packet Exchange opere opa vu e Hezeland C lup Rack Mounting th TUSS Q A sd nett en dra tav pai etel i ob xin SM Rear Panel uet rrr EE o Module Removed from Chassis eoe ort bre eo Eten aye e tene Se uae Drive Outline Draw inps cec D teh digo eate S Ee EAR DU Ret Module Outline Drawing uideo eie o et un eee esate teeta dae Data Rate and Cable Length for 5 423 ee Interface Selection Jumper Pin Locations uiae her esten Sete ev dyes Factory WIEBITBSu unida a ma M awn es Installation of Run Indicator ue e Toc eO ous TABLES Operator Trouble Isolation vede rr o ERROR Command Packet Structure Instructio oun care te atleast ana Data PACK CUS ead e at cde End PAC CU MT TC T TEM TU58 Module Connections cuero e e e va ur a rto rr EP EARN eM CHAPTER 1 INTRODUCTION 1 1 SCOPE The TU58 DECtape II is a low cost mass storage device which may be used in a wide variety of applications This manual provides the information that a user needs to install interface and com mand the operation of the tape system For information about the operation ofthe TU58 under DEC operating systems refer to the individual system
29. e is not fastened to the hub but is held in place by the elastomer belt and by the tape s wrap around itself The procedures for looping the tape back onto the hub help the user prevent important data loss do not substitute for the customary precautions of proper handling and backup copying Two procedures are given here One is for the metal base cartridge and the other is for the plastic base cartridge These are moderately difficult procedures requiring the use of small tools Minimum tools are a no 1 Phillips head screwdriver and a small probe a straightened paper clip can be used for the metal base cartridge and a 5 mm 3 16 in flat blade screwdriver and probe for the plastic base cartridge Twee zers are helpful NOTE Keep magnetized tools away from the bulk of the tape and do not touch the tape surface except at the ends because fingerprints cause errors If staples or paper clips stick to a tool it is magnetized 2 5 2 5 1 Metal Base Cartridge Tape Rethreading Procedure l Open the cartridge by removing the four baseplate Phillips head screws Figure 2 5 and set it upright on the work surface with the cover still on Lift the cover off NOTE To remove the head gate swing it out to clear the tape before lifting it up Its replacement is optional Thread the end of the tape around the tape guides Figure 2 6 Moisten the end of the tape with water to get it to stick to the hub With a small amount of slack at the
30. ecorative bezel has a small compartment that can be used to store up to six cartridges in their boxes DRIVE O DRIVE 1 222 RUN INDICATOR gt ad DRIVES RUN INDICATOR DRIVE TAPE STORAGE AREA MA 2381 Figure 2 1 TUS8 CA Rackmount Front Pane 2 1 2 Run Indicator Each tape drive has an LED that lights to indicate tape motion Since data loss can occur if a cartridge is removed while the tape is being written the cartridge should not be removed if the light is on 2 1 3 Application and Removal of Power The TUS8 CA does not have a power switch If an outlet is available on a system power controller the TUSS8 may be plugged into the controller Otherwise it does not need to be turned off Its idling power consumption is less than 20 W When power is applied the TUS8 initializes itself performs its internal diagnostic tests and then asks the host for an acknowledgement before it settles down to wait for instructions Refer to Paragraph 3 2 3 for a description of the required exchange If power is removed while a tape is being written data may be lost There are no other restrictions on power removal 2 1 2 0 TUS8 COMPONENTS CONTROLS AND INDICATORS Refer to the options section Chapter 5 for installation and operation of OEM features 22 1 Application and Removal of Power The TUS58 may be supplied with power from a host system It is ready for operation within second of voltage stabilization It does not need t
31. he bottom Make sure that the case is completely closed around the front piece of adhesive tape around the case at the mirrow window will keep it securely closed when combined with the label at the back The mirror is not used Now use a finger to operate the drive roller and wind the tape about 20 turns onto the takeup hub before inserting the cartridge into a drive NOTE The only reason for performing this exercise is to copy the data from the injured tape as soon as pos sible Discard the cartridge after copying CHAPTER 3 PROGRAMMING 3 1 GENERAL PRINCIPLES The TUSS is controlled by a high level command set that unburdens the host computer from device related operations such as tape positioning and read retries The TU58 firmware contains subroutines that are activated by brief strings of command bytes The command strings contain the numerical code for the operation to be performed and the location and size of data files that are to be transferred when applicable They also contain various housekeeping characters that are part of the Radial Serial Protocol RSP under which the byte sequences are defined The byte sequences are called message packets and are designed to be suitable for transmission by asynchronous interfaces 3 1 1 Block Number Byte Count and Drive Number The TUSS8 uses the block number and byte count to write or retrieve data If all of the desired data is contained within a single 512 byte block the byte c
32. ide buildup can cause operating systems may pro errors Paragraph 2 4 3 vide this or a similar mes 2 The tape may contain errors that were written onto it sage If a tape is in poor condition or if data is not verified at write time errors may become a permanent part of the recording TU58 sends motor stopped This indicates that a malfunction has occurred in the data error messages recovery section and the runaway timer has stopped the motor The TU58 should not be commanded to move tape more than twice under these conditions without checking the cartridge Make sure that the tape is not getting near the end where it might come free of the hub 2 4 3 Cartridge Wear Cartridge tape is expected to last for 5000 end to end and back passes If a cartridge is at the end of its life a read operation may require several retries to get the data in the presence of soft errors A soft error is a temporary data loss which is usually caused by a speck of dirt or oxide on the tape or head surface This speck lifts the tape away from head and causes signal loss and consequent read errors A few extra passes of the tape past the head may knock the speck away and allow error free reading If it happens often the tape is probably old and shedding oxide and should be copied and discarded as soon as possible 2 5 CARTRIDGE REPAIR Under unusual circumstances of controller failure or cartridge mishandling the tape might come free of the hub The tap
33. ignal is defined in the RSP specification as a unique logic entity that can be interpreted as signal regardless of the state of the protocol Its implementation for the 58 is the break condition on serial line Break is transmitted when the serial line is kept in the space condition for more than one character time This causes the TUS8 s UART to set its framing error bit The 58 will interpret the framing error as break Break has two applications in the 58 one is routinely used and the other is for special conditions When the TUSS is powered it performs its internal checkout and initialization and then transmits INITS continuously to the host to inform the host that it is present The host acknowledges the TU58 by sending break for a minimum of one character time and then sending two INITs The TU58 responds with Continue and enters an idle state in which it will wait for further instructions If communications break down due to any transient problem the host may restore order by sending break and INIT as outlined above Whatever faulty operations were underway will be cancelled and the TUSS will reinitialize itself return Continue and wait for instructions With DEC serial interfaces the initialize sequence may be sent by the following sequence of oper ations Set the break bit in the transmit control status register then send two null characters When the transmit ready flag is set again remove the break bit Thi
34. ion has to cope with the fact that the TU58 only has 128 bytes of buffer space It is necessary for the host to send a data packet and wait for the 58 to write it before sending the next data packet This is accomplished using the continue flag The continue flag is a single byte response of 0001 0000 from TUSS to host The write operation is shown for both write and write verify operations in Figure 3 2 HOST TU58 COMMAND PACKET WRITE 620 BYTES CONTINUE 128 BYTES TAPE POSITIONS AND WRITES DATA CONTINUE DATA 128 BYTES TAPE POSITIONS AND WRITES DATA CONTINUE DATA 128 BYTES TAPE POSITIONS AND WRITES DATA CONTINUE DATA 198 BY TES TAPE POSITIONS AND WRITES DATA CONTINUE DATA 108 BYTES TAPE POSITIONS AND WRITES DATA TU58 ZERO FILLS REMAIN ING 404 BYTES OF BLOCK IF WRITE VERIFY TAPE REWINDS AND READS BLOCKS JUST WRITTEN AND TESTS CHECKSUMS END SUCCESS FAILURE MA 2377 Figure 3 2 Write Command Packet Exchange 8 OP CODE 4 Reserved OP CODES Position This command causes the TUSS to position tape on the selected drive to the block designated by bytes 10 11 After reaching the selected block it sends an end packet No modifiers are used OP CODE6 Reserved OP CODE7 Diagnose This command causes the 58 to run its internal diagnostic program which tests the processor ROM and RAM Upon completion TU58 sends an end p
35. med to have enough buffer capacity to accept the entire transaction whereas the TU58 only has 128 bytes of buffer space For write commands the host must wait between message packets for the TUS8 to send the continue flag 00010000 before sending the next packet Since the host has enough buffer space the TUS8 does not wait for a continue flag Instruction NOP INIT Read Write Reserved Position Reserved Diagnose Get Status Set Status Reserved Reserved between message packets when it sends back read data 3 4 3 33 End Packets Table 3 3 Data Packets Byte Contents Flag 0000 0001 Byte Count M 2 First Data Byte 3 Data M Data Mtl Last Data Byte M 2 Checksum L Checksum H The end packet is sent to the host by the TUS8 after completion or termination of an operation or on an error The end packet is shown in Table 3 4 The definition of bytes 0 1 12 and 13 are the same as for the command packet The remaining bytes are defined as follows Byte 2 Byte 3 Byte 4 Byte 5 Bytes 6 7 Bytes 8 9 Bytes 10 11 Op Code 0100 0000 for end packet Success Code 0 Normal Success 1 1 Success but with Retries Failed Self Test 2 Partial Operation End of Medium 8 Bad Unit Number 9 No Cartridge 11 Write Protected 17 Data Check Error 32 Seek Error Block Not Found 33 Motor Stopped 48 Bad Op Code 55 Bad Record Number Unit Number 0 or 1 fo
36. n identifying number or label recorded on the tape If a cartridge is changed during a session the TU58 will not know that a different cartridge was loaded the operator must keep track of the contents of various cartridges 2 3 4 Write Protect Tab Each tape cartridge has a movable tab which when properly positioned protects data on the tape from unintended write operations When this Write Protect tab Figure 2 3 is in the inner position toward the drive roller it locks out the write circuitry WRITE PROTECT TAB IN PROTECT POSITION MOVE TO RIGHT TO RECORD MOVE TO LEFT TO PROTECT d MA 2359 Figure 2 3 Write Protect Tab When the Write Protect tab is in the outer position it closes a switch in the chassis and allows the controller to write when it is commanded to The operator should be sure that system or program tapes are backed up with copies before loading them into the TU58 with their Write Protect tabs set to record The Write Protect tab can be completely removed for long term write protection On the metal base cartridge lift the protect tab with a fingernail under the protruding end Replace it by dropping it into its slot and pressing on it until it snaps On the plastic base cartridge pry up the tab from its back edge partway and then lift from the front To replace it drop it into its slot and press forward and down 2 3 5 Cartridge Storage and Care Store cartridges in their cases aw
37. o be turned off when not in use its idling power consumption is less than 5 W When power is applied the TU58 initializes itself performs its internal diagnostic tests and then asks the host for an acknowldgement before it settles down to wait for instructions Refer to Paragraph 3 2 3 for a description of the required exchange If power is removed while a tape is being written data may be lost There are no other restrictions on power removal 2 3 CARTRIDGE 2 3 1 Cartridge Loading The TU58 drive is designed to make correct loading easy To load the cartridge hold it label up line it up with the grooves in the chassis and slide it in with a firm push Figure 2 2 illustrates the fit of the cartridge into the drive chassis grooves MA 2375 Figure 2 2 Loading a Cartridge 2 2 2 3 2 Cartridge Unloading Unloading the cartridge is as simple as loading Just pull it straight out It is best to wait for the tape to stop as indicated by the run light before removing the cartridge The mechanism cannot be damaged by removing the cartridge while the tape is moving but if a write is in progress data may be lost An error message will be sent to the host ifa command is interrupted by removal of a cartridge Cartridges should be removed from the drives when the system is not being used to prevent formation of flat spots on the motor puck 2 3 3 Keeping Track of Cartridges In non file structured systems the cartridge does not have a
38. ons When the 58 or BB Paragraph 1 5 is integrated in a host device such as a terminal convection provides adequate cooling if the interior temperature is below 50 C 122 F dry bulb 26 C 79 F wet bulb 1 5 Maximum dissipation TUS58 CA TU58 AB TU58 BB Temperature TU58 CA operating TU58 CA nonoperating Medium operating temperature Maximum temperature differ ence between system ambient and TUS8 module Relative Humidity non condensing 58 operating Maximum wet bulb Minimum dew point Relative humidity TU58 nonoperating Medium nonoperating 1 5 CONFIGURATIONS 120 Btu hour 34 Btu hour 15 C 59 F to 32 C 90 F ambient 34 C 30 F to 60 C 140 F 0 C 32 to 50 C 122 18 C 32 4 26 C 79 2 C 36 F 20 to 80 5 to 98 10 to 80 CAUTION If a cartridge has been exposed to either the maximum or minimum temperature extreme the tape should be rewound one complete cycle before using Paragraph 2 3 5 This is done to bring the tape to the proper tension The TUSS is available in the following configurations with accompanying designations Components 58 TUS8 BB Subsystems 58 Serial interface controller module surface mounting with drive Serial interface controller module surface mounting with two drives Rackmount two drives serial interface controller module power supply 110 220 V switch selectable
39. operate at a time 1 4 78 7 b cm 315 b cm 200 b in 800 b in INTER HEADER RECORD COMPL DATA SYNC DATA SPACE CHECK RECORD SYNC NUMBER OF RCD 128 BYTES SUM SPACE MARK NUMBER ALLZEROS 000 01 1024 N 1024 00 00 00 00 01 TRK1 TU58 ARRANGES FOUR RECORDS AS ONE BLOCK MA 2371 128 384 129 385 130 Figure 1 5 Block Locations on Tape MA 2373 1 42 Electrical Power consmption Module and 1 or 2 drives 11 W typical drive running 5 V 5 at 0 75 A maximum 12 V 10 5 at 1 2 A peak 0 6 A average running 0 1 A idle These voltages need not stabilize simultaneously upon power on Rackmount 90 128 180 256 Vac 47 63 Hz 35 W maximum Serial interface standards In accordance with RS 422 or RS 423 compatible with RS 232 C 1 4 3 Mechanical Drive 81H X 8 3 D X 10 6 W cm 3 2 X 3 3 X 4 1 in with 19 7 5 in cable Board Module 13 2 H X 26 5 D X 3 5 W cm 5 19 X 10 44 X 1 4 in Rackmount cabinet 13 2 38 1 DX 48 3 W 5 19 X 15 0 X 19 0 in Power connector to module AMP 87159 6 with 87027 3 contacts DEC part nos 12 12202 09 12 12203 00 Power connector to rackmount European IEC standard Interface connector to module AMP 87133 5 with 87124 1 locking clip contacts and 87179 1 index pin DEC part nos 12 14268 02 12 14267 00 12 15418 00 1 4 4 Environmental The TU58 meets the following environmental specificati
40. operates on full duplex asynchronous 4 wire lines at rates from 150 baud to 38 4 kilobaud The transmit and receive rates may be independently set Each 8 bit byte is transmitted with one start bit one stop bit and no parity The line driver and receiver may be set to operate in accord ance with EIA RS 422 balanced or RS 423 unbalanced signal standards When set to RS 423 the TUSS is compatible with devices complying with RS 232 C 4 8 The TUSS is shipped prewired for operation at 38 4 kilobaud transmit and receive on RS 423 The maximum wire length that may be used at that data rate in an electrically quiet environment like an office is approximately 27 m 90 ft The wire used with any installation should be no less than 24 AWG diameter Longer wire runs may be made if data rates are reduced RS 422 is considerably more noise immune than RS 423 and can be used over at least 1200 m 4000 ft at any TU58 data rate Figure 4 7 derived from the EIA standards illustrates the variations in distance needed by RS 423 for different data rates For more information consult the standards for RS 422 and RS 423 published by the Electronic Industries Association 1200 300 M 150 M CABLE LENGTH 30 M 15 M FT 300 600 1K 2K 5K 10K 20K 40K DATA RATE IN BAUDS RS 423 MA 2368 Figure 4 7 Data Rate and Cable Length for RS 423 4 3 2 Connecting Standards Jumpers The jumper pins are standard 0 635 mm 0 025 in wire wrap post
41. ount will be 512 or less When the host asks for a particular block and a 512 or less byte count the TU58 will position the specified drive unit at that block and transfer the number of bytes specified If the host asks for a block and also a byte count greater than that of the 512 byte boundary the TU58 will read as many sequential blocks as are needed to fulfill the byte count The same process applies to the write function This means that the host software or an on tape file directory need only store the number of the first block in a file and the file s byte count to read or write all the data without having to know the additional block numbers 3 1 2 Special Handler Functions Some device related functions are not dealt with directly in the RSP or in the TU58 firmware 1 short routine perhaps entitled Newtape should be included in a TU58 handler to provide a complete wind rewind for new or environmentally stressed tape cartridges This procedure brings the tape pack to proper operating tension levels 2 TUSS handler should check the success code byte 3 of the RSP end message for the presence of soft errors This enables action to be taken before hard errors permanent data losses occur For example if the number of retries on a particular cartridge reaches some value a message like Tape Maintenance Required is presented to the operator This sug gests that prompt copying of the tape and cleaning of the head is in order
42. r Drive Number Always 0 Sequence Number Always 0 as in command packet Actual Byte Count Number of bytes handled in transaction In a good oper ation this will be the same as the data byte count in the command packet Summary Status Byte 10 Bit 7 Byte 11 Reserved Bit 0 1 2 3 4 Logic Error 5 Motion Error 6 Transfer Error 7 Special Condition Errors 3 5 Table 3 4 End Packet Byte Contents Flag 0000 0010 Op Code 0100 0000 Success Code Unit Not Used Sequence No L Sequence No H Actual Byte Count L Actual Byte Count H Summary Status L Summary Status H Checksum L Checksum H 34 THE INSTRUCTION SET Byte Count 0000 1010 The instructions and their op codes are shown in Table 3 2 The following is a brief description and usage example of each OP CODE 0 NOP This instruction causes the TUSS8 to return an end packet There are no modifiers to The NOP packet is shown below BYTE 0 0000 0010 FLAG 1 0000 1010 MESSAGE BYTE CNT 2 0000 0000 OP CODE 3 0000 0000 MODIFIER 4 0000 000X UNIT NUMBER IGNORED 5 0000 0000 SWITCHES NOT USED 6 0000 0000 SEQ NO 7 0000 0000 SEQ NO 8 0000 0000 BYTE COUNTL 9 0000 0000 BYTE COUNTH 10 0000 0000 BLOCK NO L 11 0000 0000 BLOCK NO H 12 0000 001X CHECKSUML 13 0000 1010 CHECKSUM H The TUSS returns the following end packet 0 0000 0010 FLAG 1 0000 1010 MESSAGE BYTE CNT 2 0100 0000 OP CODE 3 0000 0000 SUCCESS CODE 4 0000 000X UNIT IGNORE
43. reel packages containing 42 7 m 140 ft of 3 81 mm 0 150 in wide tape The tape is driven by a single puck which engages a roller which moves an elastomer drive belt in the cartridge This belt loops around both tape spools and provides uniform tension and spill free winding without mechanical linkages Figure 1 1 The simple single point drive mechanism allows high reliability for the entire system The control and drive circuitry of the TUSS is located a single circuit board The controller uses microprocessor uP to reduce the tape handling and communications management load on the host system 1 1 DRIVE PUCK HEAD SWINGOUT GATE WRITE PROJECT TAB DRIVE APE ROLLER T MA 2380 TAPE ELASTOMER CARTRIDGE BELT Figure 1 1 Tape Cartridge Partially Inserted into Drive Top View The motor and tape head control driver and switching circuits to manage two tape drives are on the printed circuit board with the 4P The controller supports one or two drives but only one drive can operate at a time The uP controls all of the activities of the TU58 Head and motor selection speed and direction changes etc are managed by outputs from I O ports on a peripheral IC The mechani cal actions of the drives themselves are supervised by the uP to improve the system s performance Operational amplifiers comparators and logic circuits perform amplification signal switching and conditioning proportional control
44. s in the packet excluding the four message delivery bytes This is decimal 10 for all command packets 12 13 Checksum The 16 bit checksum of bytes 0 through 11 The checksum is formed by treating each pair of bytes as a word and sum ming words with end around carry Table 3 1 Command Packet Structure Byte Contents 0000 0010 Message Byte Count 0000 1010 Op Code Modifier Unit Number Switches Sequence Number Low Sequence Number High Byte Count Low Byte Count High Block Number Low Block Number High Checksum Low Checksum High 3 3 The remaining bytes are defined as follows 2 Op Code 3 Modifier 4 Unit Number 5 Switches 6 7 Sequence Number 8 9 Byte Count 10 11 Block Number Operation being commanded Refer to Table 3 2 and Para graph 3 4 for definitions Permits variations of commands Selects drive 0 or 1 Always zero for TUS8 Always zero for TUS8 Number of bytes to be transferred by a read or write com mand Ignored by other commands The block number to be used by commands requiring tape positioning Table 3 2 Instruction Set 3 3 2 Data Packets The data packet is shown in Table 3 3 The flag byte is set to 00000001 The number of data bytes may be between 1 and 128 bytes For data transfers larger than 128 bytes the transaction is broken up and sent 128 bytes at a time The host is assu
45. s which may be connected using 30 AWG wire and a hand tool Other techniques that may be used include slip on connectors such as DEC H821 Grip Clips 915 patchcords 917 daisy chain or soldering The baud rates may be set independently for transmission and reception or both can operate together Simply connect the pin with the desired baud value to either the XMIT or RCV pins or both Figure 4 8 illustrates the pin locations and Figure 4 9 shows the factory wired configuration The interface standards may be selected by connecting sets of pins together The connections are listed in abbreviated form in Figure 4 8 The group of pins 17 through 24 are the interface pins The module is shipped prewired for RS 423 with pin 17 connected to pin 19 and pin 18 connected to pin 20 No other pins in the group are connected For RS 422 pin 21 should be tied to pin 19 pin 22 to pin 20 and pin 23 to pin 24 No other pins in the group are connected DIAGNOSTIC LED WW or rei c GND lo Et S m 150 WW 600 1200 2400 5 gt 4800 END VIEW 9600 19 2 232 17 19 t RCV CLK n 423118 20 XMIT FCLK AUX A4 422 AUX B YA 21 19 WW WW 22 20 24 17 23 24 m N Loin e e N ESETE o i amp olala 2366 Figure 4 8 Interface Selection Jumper Pin Locations MA 2383 4 43
46. s will time Break to be one character time long The second character will be discarded by the TU58 controller Next send two INIT characters The first will be discarded by the TU58 The TU58 will respond to the second INIT by sending Continue When Continue has been received the initialize sequence is complete and any command packet may follow 3 3 COMMAND SET The command set for the TU58 provides the capabilities required for the performance of random access operations To allow for future development certain op codes in the command set have been reserved these commands have unpredictable results and should not be used Op codes not listed in the command set are illegal and result in the return of an end packet with the bad op code success code A data transfer operation uses three or more message packets The first packet is the command packet from host to the TUS8 Next the data is transferred in 128 byte packets in either direction as required by read or write After all data is transferred the TUS58 sends an end packet If the TU58 encounters failure before all data has been transferred it sends the end packet as soon as the failure occurs 3 3 1 Command Packets The command packet format is shown in Table 3 1 Bytes 0 1 12 and 13 are the message delivery bytes Their definitions are as follows 0 Flag This byte is set to 00000010 to indicate that the packet is a Command packet Message Byte Count Number of byte
47. t around the hub The hub should seat against the base with the belt around it 2 5 2 2 Threading the Cartridge 1 Pull several centimeters a few inches of tape off the supply hub and through the tape guides Figure 2 11 NOTE Hold all parts down when moving them Otherwise the hubs will creep up the pins and cause the belt to slip Then the procedure must be restarted at Para graph 2 5 2 1 2 Moisten the end of the tape with water to get it to stick to the hub 3 With a small amount of slack at the free end insert the end between the hub and belt and operate the floating roller to take up the tape FLOATING ROLLER MA 2355 MA 2364 Figure 2 10 Stretch the Belt with the Floating Roller Figure 2 11 Threading the Plastic Base Cartridge 4 As soon as the tape is grabbed keep some back tension on the tape This keeps the tape feeding straight into the hub 5 Continue to wind Watch for the loose end as it comes around If it separates from the hub tuck it under the next turn of tape with the paper clip Back up if the end is too long 6 Continue to wind a few more turns with the floating roller while applying tension to the tape 7 Now hold the takeup hub drive and floating rollers fixed and rotate the supply hub to take up the slack 2 5 2 3 Closing the Cartridge The case should fold closed on its label hinge Do not reinstall the head gate The mirror window may need to be pressed in slightly to clear t
48. ts i sarei E eee ERA Cea va veis qu 4 9 OPERATIONAL CHECK Oei a ER pr 4 11 Cheekoubolf INEGI ACE dots ore e 4 11 Checkout of RSP and Command Function secs 4 11 OPTIONS RUNTINDICATOR esteem Exe mide DOOR 5 1 Installationen Oo OR um onto See e odi e uta 5 5 2 FIGURES Title Page Tape Cartridge Partially Inserted into Drive Top 1 2 An Exchange in Radial Serial Protocol essen 1 3 T I58 Block DI 1 3 Simple Record on 1 5 Block Locations on E e aule Ren epa su as 1 5 REPLY p t DB U N FIGURES Cont Title TU58 CA Rackmount Front Panel eee enne Loading aC ALG OO Le Medeae A eite Protect Dior bata View Into Tape Drive Cartridge Slot coe ae Metal Baseplate Screw Locations n Threading Metal Base Head Gate and Spring itin o e bern Qd Wane E EA Open the Plastc Base Cartridge ends Oa a Ete bri e gus Welded Case Halves Separated uetus entire evene to oce oy ex vel eer den Ee mre iere dao Stretch the Belt with the Floating Threading the Plastic Bas
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