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Document:	EK-0TU58-UG-004 TU58 DECtape II Users Guide Dec83
Order Number:	EK-0TUS8-UG
Revision:	004
Pages:	96
Original Filename:

OCR Text

EK-OTU58-UG-004

TUS8 DECtape II
User Guide

, EK·OTU58·UG·004

TUS8 DECtape II
User Guide

Prepared by Educational Services
of
Digital Equipment Corporation

1st Edition, October 1978
2nd Edition, June 1981
3rd Edition, October 1982
4th Edition, December 1983

Copyright () 1978, 1981, 1982. 1983
by Digital Equipment Corporation
All Rights Reserved
The reproduction of this material, in part or whole, is
strictly prohibited. For copy information, contact the Educational Services Department. Digital Equipment Corporation, Maynard, Massachusetts 01754.
The information in this document is subject to change
without notice. Digital Equipment Corporation assumes no
responsibility for any errors that may appear in this
document.
Printed in U.S.A.
This equipment generates, ml.($, and may emit radio fre~
quency. The equipment has been type tested and found to
comply with the limits for a Class A computing device
pursuant to Subpart J of Part 15 of FCC rules, which are
designed to provide reasonable protection against such
radio frequency interference. Operation of this equipment
in a residential area may cause interference in which case
the user at his own expense will be required to take
whatever measures may be required to correct the
.interference.
The following are trademarks of Digital Equipment Corporation, Maynard, Massachusetts.
DEC
DECUS

DIGITAL

DECnet
DECsystem-l0
DECSYSTEM-20
DECwriter

OMNIBUS

OS/8
PDT
RSTS

RIIID

DIooL

RSX

UNIBUS
DECtape
DECtape II

EduSystem
VAX
MASSBUS

VMS
lAS
VT

CONTENTS

CHAPTER 1 INTRODUCTION
1.1

Scope ... "' ... ........ "' ...... " . " ...... " " ...... " " ...... " " "' . "' ......... " . "' ........... " ..

1-1

1.2
1.3
1.3.1

General Description ..............................•..........•.......
Block Diagram .......................... . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Control ... , ,... " . . . . . . . .. . ....... . ........ , .... " ....... ,.

1-1
1-3
1-3

1.3.2

Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1.4
1.4.1
1.4.2

Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . .
Performance . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical ...........................................•...........

1-4
1-4
1-5

1.4.3

Mechanical" .......... "....... "'"." "" .... ". ".,,"' "'"'." """ . "'''''"."' .. ,,"' "'.,,"' ""'. '"

1-6

1.4.4
1.S
1.6
1. 7

Environmental ................. . . . . . . . . . . . • . . • . . • . • . . • . . . . . . . . . . . 1-6
Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . 1-7
Hardware Documentation Ordering Information ' ........ " ........ , , ........' 1-9
Digital Repair Service ........•.......•.......................•.•... " 1-10

CHAPTER 2 OPERATION
2.1
2.1.1
2.1.2
2.1.3
2.2
2.2.1

2.2.2

2.2.3
2.3
2.3.1
2.3.2
2.3.3
2.4
2.4.1
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.6.1
2.6.2
2.6.3

TU58-DA, -CA Rackmount Controls and Indicators ........•....•.....•....
Front Panel .•..............................................•....
Run Indicator. . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . • . . • . . . . . . . . . .
Application and Removal of Power ...................................
TU58·EA, -EB Controls and Indicators ...........................•......
Front Panel ".""""""1O""""" .. "" .. .,,,,,,,,,,,,,,, ... ,,,,,,,,,, '" " " " " " .. " • " ,. .. " " " " ,. " " ..
Run Indicator" """""""" " " " " " " " " " " " . " " " " . " " " " " " " " " " " " " ... " " " " " " " " " " ~
Application and Removal of Power ...................................
TU58-VA Controls and Indicators ...............•......•..•.••.....•.•.
Front Panel •........................................•...........
Run Indicator. • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • • . • . • • • • . . . . . . . . . .
Application and Removal of Power ..•.......•.•..•..•................
TU58 Components Controls and Indicators ...•......... ' ...•... , ........ .
Application and Removal of Power .........•.........................
Cartridge .
Cartridge Loading. . . . . . . . . . . . . . . . . . . • • . . . . . . . • • . . . . • • . . . . . . . . . . . . .
Cartridge Unloading • . . • . • . • • • • . . . . • . • • . . . . . . . • . . . . . . . . . . . . . . . . . . . .
Keeping Track of Cartridges. . . • . . . . . . • . • . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Write Protect Tab. . . • . . . • . • . . . . . • . . . . . . . . . . . . . . . . . . . . . . . • . . • . • . . . .
Cartridge Storage and Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.Maintenance .. , ,. ....... ,. ........ ,. •..... ,. , ............ , . , . , . . . . . . . . .
Head and Puck Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operator Trouble Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cartridge Wear •.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
it

•••••••

•

••••

•

iii

•••••

•

••

••••

...

••

•

2-1
2-1
2-1
2-1
2-2
2-2

2",,2

2-2
2-2
2-2
2-2
2-3
2-3
2-3
2-3
2-3
2-3
2-3
2-S
2-5
2-S
2-S
2-S

·CHAPTER 3 PROGRAMMING
3.1
3.1.1
3.1.2
3.2
3.2.1
3.2.1.1
3.2.2
3.2.3
3.2.3.1
3.2.3.2
3.2.4
3.2.4.1
3.2.4.2
3.2.5
3.3
3.4

General Principles .......................•.............•............. 3-1
Block Number, Byte Count, and Drive Number ............••.•..•......• 3-1
Special Handler Functions ....•...••.•.••.•...........•............. 3-1
Radial Serial Protocol (RSP) and Modified RSP (MRSP) ......•.•...••..•..•. 3-1
Packets ....... """"""". """"""". """"""""""""""""". ". ", "". ". ". """"... 3-1
Packet Usage "".""""" ... ". """" .. """.".""""""".,."" ... "".,." . "., .. " 3-2
Break and Initialization "."""." .. "."" .... """.,,, ... ,,.,, . , . ,,.,,,,,,,,,,,,, .... ,,,,,,,,. 3-3
Command Packets . """".,,,.,,,,,,,," ... ,,.,,,,,, . , . ,,.,,,,,,,,,,,,,,,,.,, ... , .... ,,,,,,.,, ... 3-3
Maintenance Mode ...........•............•.•................... 3-4
Special Address Mode ...•.•.•..........•••.....•••...........•... 3-4
Data Packets" ". "". """, . ".... """".... ". "...... """"... "". ". ".... "".... "". """. ", 3-4
Radial Serial Protocol .......................••..•......•......•.. 3-4
Modified Radial Serial Protocol ...........•......•...••...•..•.•.•• 3-4
3-5
End Packets . "... ". ". "....
3-6
Instruction Set .... ".. "". ".... "....... "......... ". "... ., "....... "..... ". ". ".... "........ "... ""
3-11
PASCAL TU58 Handler Algorithm Definitions
to

......

...

.....................

...

....

.......

•

CHAPTER4 INSTALLATION
4.1

4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.3

Introduction" . " , """"" , "", , """""""", """"". """"""""""""""" . " "" """""""

Rack Installation (-DA Version) . . . . . . . . . . . • • • . • . . . • . . . . . • . •. •• . • . . • . . . .
Rackrnount . """"""""""""""" .... ,
Unpacking . """ . """""".""." •. ".. """""""."" . , ... ,,",, .... ,,"",, ... ,,""""""
Power Selection "" . """""""" . ".""" . "."."."""" .. ,,""",,.,,"""",, . ,,"",,.,,"
Removing Bottom Plates for Controller Board Configuration ............•.•
Rackmounting Procedure. . . . . . . . . . • . • . . . • . • • • • • • • . • • • . • • . . . . • . . . • • •
Rack Installation (-CA Version) . . • . . . . . . . . . . . . . . • . . • . . • . . • • • . . . • . • • • • • .
111

•

4-1

4-1
4-1
4-1
4-1
4-2
4-2
4-7

4.3.1

Rackmount """." . ". ""."""""""".""."."""""""""" ... "".""" .... ",, ... ,,,,....

4-7

4.3.2
4.3.3
4.3.4
4.4
4.4.1
4.4.2
4.5
4.5.1
4.5.2
4.5.3

Power Selection for the Rack Version .....•.....•••••.••.••..•.••..•..
Removing Module from Chassis. • • . • . • . . .. . • • • •• • • . . • . • • . . .. . . . .. . • •.
Reinstalling the Module ..••..•.............••••.•.•••••.••••.•••.•.
Installation (-EA and -EB Versions) .....................................
Tabletop Installation .....••..•.............•.•••.....•.••.••..••.•
Solid Mounting Installation .........................................
Installation (-VA Version) .•••..•.•....•.••..•...•......•••.••••.••.•.
Tabletop Installation .•........•••.•••••••....•.••••..•.••........•
Solid Mounting Installation .......•.•.•...............•...•...•..••.
Mounting the TU58-VA to the SBll (or BAll-VA) ......................

4-8
4-10
4-10
4-12
4-12
4-12
4-13
4-13
4-13
4-13

4.6

Components" ... , """"""", """"""""""""""e." .... " .. " " " " " .. " " " " " " " " • " " . . . . . . .. " 4-13

4.7
4.7.1
4.7.2
4.8
4.8.1
4.8.2
4.8.3

Interface Standards Selection and Setup ...•••..•.•..•.....•..•..........
Selecting Interface Standards.. • . • . . • •• • . • . • . . . . • • . . • . ... • • . • .. . •. . •.
Connecting Standards Jumpers ..•..•.•......•..•••..••..•.•.....•....
Operational Checkout .....••••.•......•......•.••..•..........••••.•
Checkout of Interface •.•......•••••••.•..•••.••...•••...•....•....
Configuring Interface Modules •• • • . • . . . . . . . . . . . . • . • • . • • . • . . • • . . . . • . .•
Checkout of Drive Command Function ...••...........••....••........

4-16
4-17
4-19
4-19
4-19
4-21
4-31

CHAPTER S OPTIONS
5.1
5.1.1
5.2
5.2.1
5.2.2
S.2.3

Run Indicator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .
Boot Switch.......................................... .....................................................................
General.............. ................ .......... ...........•.....
Operation ......................................................
Installation~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
e" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

................

5-1
5-1
5-2
5-2
5-2
5-2

APPENDIX A TUS8/pDP-ll TOGGLE-IN BOOT
APPENDIX B RSP SEQUENCE
APPENDIX C SAMPLE DEVICE HANDLERS
APPENDIX D CARTRIDGE REPAIR
APPENDIX E FffiLD REPLACEABLE UNIT SPARES LIST
FIGURES
I-I
1-2
1-3
1-4
2-1
2-2
2-3
2-4
2-5
3-1
3-2
3-3
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4·10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20

Tape Cartridge Partially Inserted into Drive (Top View) •.......•............
An Exchange in Radial Serial Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TU58 Block Diagram .........................................................................................
Block Locations on Tape ...........•........................•..•.....
TU58-DA and -CA Rackmount Front Panel. • • • . . . . . . . . . . . . . . . . . . . . . . . . . . .
TU58-EA, -EB, and -VA Front Panel ............. . . . . . . . . . . . . . . . . . . . . . . .
Cartridge Loading. . . . . . • • . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . .
Write Protect Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . .
View Into Tape Drive Cartridge Slot ....................................
Read Command Packet Exchange ......................................
RSP Write Transaction . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . .
MRSP Write Transaction ............................................•
TU58-DA Rear Panel ................................................................................
Installing Support Brackets ..................................•...•....
Installing Mounting Brackets ••......•.......•.........................
Front Vertical Rail U-Nut Retainers. . . . . . . . . • . . . . . . . . . . . . . . . . . . • . • . . . . . .
Rackmounting the TU58·DA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . .
Rear Vertical Support U-Nut Retainers ..•.....•..........•...•..........
Fastening Support Bracket Extenders ...•......................•........
Installing the Bezel . • . • . . • . . . . . . • . . . • . • • • . • • • . . . . . . . • . • . . . • • • • . . . • • . . . . .
Bezel and Ball Stud .................... '" . • . . • • . • . . . • . • . . • . • • • . . . • • . • . . . .
Rackmounting the TU58-CA ..........................................
TU58-CA Rear Panel ................ ". . . . . . . . . . . . . . • • . • . . . . . . . . . . . . ..
Installing Cage and Retainer Bar. • . . . . . . . . . . .. . . . . • . . . . . . . . . . . • • . . . . . . ..
Mounting the TU58-EA and -EB .......................................
Mounting Choices for the TU58·VA . • . . . . .. . . . .. .. . .. .. . . . . .. . . . . . .. . ...
Interfacing the TU58-VA ..•...••.. '. ........•...•••...•...............
Drive Outline Drawings . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . ..
Board Outline Drawings •. • . . . . . . . • • . . • . • • . • . . • • • • . • . • . • • . . • . . • . . • . . . ..
TU58 Drive Mounting Hardware .......................................
Data Rate and Cable Length for RS-423 ............••.......•.•.........
Interface Selection Jumper Pin Locations ..•...............•.............

1-2
1-3
1-4
1-5
2-1
2-2
2-4
2-4
2-5
3-8
3-9
3·10
4-2
4-3
4-4
4-4
4-5
4-6
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-14
4·14
4-15
4-16
4-17
4-19
4-20

4-21
4-22
4-23
4-24
5-1
D-l
0·2
0·3
D-4
0-5

Factory Wiring ".. "....... ".... ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
TUS8 Wiring (9600 Baud) ............................................
OLVII-J Factory Conftguration Summary ...............................
MXVII-A Jumper Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . ..
Installation of Run Indicator ..........•...•. . . . . . . . . . . . . . . . . . . . . . . . . . .
Baseplate Screw Locations ....... "". """"""... ". ".. ""....... ". ". ". ". . . .
Threading the Metal·Base Cartridge •.•...•.....•........................
Head Gate and Spring. . . • . • . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Stretch the Belt with the Floating Roller . . . . . . . . • . . . . . . . . . . . . . . . . . . . • . . . .
Threading the Plastic-Base Cartridge. . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . ..

4-21
4-21
4-25
4-26
5-1
0-1
0-2
0-3
0-3
D-4

2-1

Operator Trouble Isolation. . • . . • . . . . . . . • . . . . . . . . . . . . • . • . . . . . . . . . . . . • . .

2·6

3-1

Command Packet Structure ... ".""" .... "" ...... "... "... "... "" .. ".".,,

3-3

3-2
3-3
34
4-1
4·2

Data Packets" .... "... "".. ".. ""... "...... "...... "............ ".. ". . . 3-5
End Packet . • • . . . . . . . . . • • • . • . • . . . . . . . . . . . .. . • • . . . . . • • . . • . . . • . . . . . • • . 3·5
Instruction Set "" ". ". ". . "". ". "".. ". "... ". "". "". ". . . ". """. . ". "". . . """ 3-7
TU58 Module Connections .....•.............................•........ 4-18
MXVII-A Standard Factory Conftguration ............................... 4-27

TABLES

•

CHAPTER 1
INTRODUCfION

1.1 SCOPE
The TU58 DECtape II is a low-cost, mass-storage device that may be used in a wide variety of applications.
This manual provides information that a user needs to install, interface, and operate the tape system. (For
specific information about using the TU58 under DIGITAL operating systems, refer to the individual system manuals.)

Chapter 1 provides a general description of the TU58 and a list of its specifications, including electrical and
mechanical requirements. The configurations section describes the available variations of the TU58.
Chapter 2 contains important information for daily operation and routine maintenance. It is the system
operator's reference section.
Chapter 3 is a programming guide. It contains functional descriptions of the TU58 command set, illustrates command sequences, explains the details of the radial serial protocol (RSP) and the modified radial
serial protocol (MRSP), lists system instruction codes and byte sequences, and includes a general purpose
programming example for a TU58 device handler.
Chapter 4 describes instructions for jumper selection; mechanical, electrical, and interface installation; and
operational checkout of the tape system.
Chapter 5 describes the optional features available in the TU58.
Appendix A lists a PDP-II toggle-in bootstrap for the TU58.
Appendix B contains an RSP sequence to exercise a new cartridge.
Appendix C lists sample device handlers written in POP-ll FORTRAN IV and PDP-ll MACRO-ll
assembly language.
Appendix 0 covers cartridge repair procedures.
Appendix E lists the field replaceable units (FRUs) in the TU58.
1.2 GENERAL DESCRIPTION
The TU58 is a random-access, fixed-length-block, mass-storage tape system. It uses preformatted tape
cartridges which store 262 kilobytes of data in 5I2-byte blocks. There are 256 blocks on each of two
tracks. They may be accessed by a program in a fashion similar to that employed for 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.

1-1

The TU58 is compact and mechanically simple. The tape cartridges are DIGITAL-preformatted, miniature, reel-to-reel packages containing 42.7 m (140 ft) of 3.81 mm (0.150 in) wide tape. A single puck
drives the tape by engaging 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 I-I). The simple, single-point drive mechanism provides high reliability for the entire
system.
The control and drive circuitry of the TU58 is located on a single circuit board. The controller uses a
microprocessor (p.P) to reduce the tape handling and communications management load on the host
system.
The motor and tape head control, driver, and switching circuits that manage the two tape drives are on
the printed circuit board with the p.P. The controller supports one or two drives, but only one drive can
operate at a time. The p.P controls all activities of the TU58. Head and motor selection, speed and
direction changes, etc. are managed by outputs from I/O ports on a peripheral integrated circuit (IC).
The mechanical actions of the drives are supervised by the p.P in order to improve system performance.
Operational amplifiers, comparators, and logic circuits perform amplification, signal switching and conditioning, proportional control, and logic steering functions in the controller. The tape is protected by
motor current limiting and an anti-runaway timer.
The p.P intelligence requires that requests from the host for data retrieval or storage contain only 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 either radial serial protocol (RSP), or modified
radial serial protocol (MRSP). 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 TU58, 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. See Chapter 3
for a full discussion of RSP implementation..
DRIVE PUCK

HEAD
MICROSWITCHES
SWINGOUT
GATE

WRITE PROTECT
TAB

DRIVE
ROLLER

TAPE

TAPE
CARTRIDGE

ELASTOMER
BELT
MA·2380

Figure I-I

Tape Cartridge Partially Inserted into Drive (Top View)

1-2

When, owing to the data transfer rate selected, the buffer is unable to accept an entire transaction, modified serial protocol (MRSP) is utilized. MRSP is implemented by using the command packet switch byte.
See Paragraph 3.2 for a more detailed description of MRSP implementation.
The serial host interface operates on full-duplex, asynchronous, 4-wire lines at jumper-selectable rates of
150 to 38.4K baud. Send and receive rates may be independently set with jumpers to operate in accordance
with Electronic Industries Association (EIA) standards R8-422 or RS-423. When set to R8-423, the TU58
is also compatible with devices complying with R8-232-C.

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 connected to the processor by an 8·bit-wide data/address bus.

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 (AGe) 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 TU58 processor bus and the host computer via the serial line drivers and
receivers.

HOST

COMMAND
PACKET

I
I

TU58

•
CONTINUE

I
•
I
.. I ICONTI~UE
I
II
I

DATA
PACKET

•

END
MESSAGE
PACKET

MA·2384

Figure 1-2 An Exchange in Radial Serial Protocol

1-3

TO HOST

Figure 1-3 TUS8 Block Diagram

1.4 SPEOFICATIONS
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

262,144 bytes, formatted in 512
blocks of 512 bytes each
41.7 ps/data bit, 24 Kbits/s
150 to 38.4 kbaud, jumper selected
5000 minimum end-to-end-and-back
tape passes
1 in 107 bits read (before selfcorrection)

Hard error rate

1 in 109 bits read (unrecoverable
within 8 automatic retries)

Hard error rate with
write-verify and
system correction

2 in 1011 bits read/written

Error checking

Checksum with rotation

1-4

Average access time

9.3 seconds

Maximmn access tirnc

28 seconds

Read/write tape speed

76 cm/s (30 in/s)

Search tape speed

152 cm/s (60 in/s)

Bit density

315 bits/em (800 bits/in)

Flux reversal density

945 fr/cm (2400 fr/in)

Recording method

Ratio encoding

Medium

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 em (2.4 X 3.2
X 0.5 in). Order TU58-K.

Track format (Figure 1-4)

Two tracks, each containing 1024
individually numbered, firmwareinterleaved "records." Firmware
manipulates four records at each
operation to form 512-byte blocks.

Drive

Single motor, head integrally cast
into molded chassis.

Drives per controller

1 or 2 (only one may operate at a
time)

1.4.2 Electrical
Power consumption
Board and 1 or 2
drives

11 W typical, drive running
cor. 5 V :t5% 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.

JBOT
(

BOT

#128
200

#384

600

#129
201

#385
601

#130
202

#256
400

#1
1

#257
401

#2
2

~lJ
#256
~3(
402

#386
602

BOT: BEGINNING OF TAPE
EDT: END OF TAPE

#254
376

#510
776

#255
377

#511

#126
176

#382
576

#127
177

#383
577

777

# DECIMAL

OCT.AL

Figure 1-4 Block Locations on Tape

1-5

~1\~;a37""

Rackmount
Serial interface standards

90- 128 Vac, 180 - 256 Vac,
47 - 63 Hz, 35 W maximum
In accordance with RS-422 or RS-423;
compatible with RS-232-C.

1.4.3 Mechanical
Drive

8.1 H X 8.3 D X 10.6 W cm (3.2 X 3.3
X 4.1 in) with 19 cm (7.5 in) cable;
0.23 kg (0.5Ib)

Board

13.2 H X 26.5 D X 3.5 W cm (5.19 X
10.44 X 1.4 in); 0.24 kg (0.53Ib)

TU58-DA

Same rackspace as -CA. See -EA for
chassis.

TU58-CA rackmount
cabinet

13.2 H X 38.1 D X 48.3 W cm (5.19 X
15.0 X 19.0 in); 9 kg (20 lbs)

TU58-EA, -EB, -VA

9.2 H X 29.5 D X 33.7 W cm (3.6 X
11.6 X 13.3 in); with rubber feet,
add 1.5 H cm (0.6 in)

Power connector to
board

AMP 87159-6 with 87027-3 contacts
DIGITAL PN 12-12202-09,
12-12203-00)

Power connector to
rackmount

European IEC standard

Interface connector to
board

AMP 87133-5 with 87124-1 locking
clip contacts and 87179-1 index pin
(PN 12-14268-02, 12-14267-00,
12-15418-00)

1.4.4 Environmental
When the TU58-AB or -BB 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.
Maximum dissipation
TU58-CA, -DA, -EA, -EB
TU58-AB, -BB, -VA
Temperature
TU58 operating

120 Btu/hour
34 Btu/hour
15° C (59 0 F) to 42° C (108 0 F) ambient

TU58 nonoperating

-34° C (-30° F) to 60° C (140 0 F)

Maximum temperature
difference between
ambient and TU58 board

18° C (32.4° F)

1-6

Relative humidity, noncondensing
TU58 operating
Maximum dew point
Minimum dew point
Relative humidity
TU 58 nonoperating .

23° C (73.4° F)
2° C (36° F)
10% to 90%
5% to 98%

CAUTION
If a cartridge bas been exposed to eitber tbe max-

imum or minimum temperature extreme, tbe tape
should be rewound one complete cycle before using.
This is done to bring tbe tape to tbe proper tension.
1.5 CONFIGURATIONS
The TU58 is available in the following configurations with accompanying designations.
TU58·CA

Rackmount, large chassis, two drives, serial interface controller board, power
supply 115/230 V switch-selectable, detachable line cords and fuses for 115 V
and 230 V, two cartridges, boot ROM for MRII-EA, User Guide, Field Maintenance Print Set (MPOO747), two I/O cables (BC17A-18 and BCI7B-18), diagnostic kit (ZJ287-RG).

TU58-DA

Rackmount, tabletop chassis, two drives, serial interface controller board, power supply 115/230 V switch-selectable, detachable line cords and fuses for 115
V and 230 V, two cartridges, two I/O cables (BCI7A-18 and BCI7B-18), boot
ROM for MRll-EA, accessory assembly hardware kit (70-16753-00), User
Guide, Field Maintenance Print Sets (MPOlOI4 and MPOI063).

TU58-EA

Tabletop, two drives, serial interface controller board, power supply 115/230 V
switch-selectable, detachable line cord and fuse for 115 V, accessory assembly
hardware kit (70-16753-00), User Guide, Field Maintenance Print Set
(MPOlOI4).

TU58-EB

Tabletop, two drives, serial interface controller board,' power supply 115/230 V
switch-selectable, detachable line cords and fuses for liS V and 230 V, two cartridges, two I/O cables (BCI7A-18 and BCI7B-18), boot ROM for MRll-EA,
accessory assembly hardware kit (70-16753-00), User Guide, Field Maintenance Print Set (MPOlOI4).

TU58-VA

Tabletop, two drives, serial interface controller board, dc power cable (7017569-1C), I/O cable (70-17568-1F), two cartridges, MXVII-A-2 boot ROM,
User Guide, Configuration Guide, Field Maintenance Print Set (MPO 10 13), accessory assembly hardware kit (70-16753-01).

Additional Supplies
NOTE
BCllO-lO replaces BCl7A-l8 and BC17B-l8. The
new cable has an improved shield connection to comply witb FCC regulations.
8C220-lO

Interface cable from TU58 to host.

1-7

BC17A-18

Interface cable from TU58 to DL-ll and DLV-ll, 5.4 m (18 ft) (lO-pin-to-40pin connector).

BC17B-18

Interface cable from TU58 to DLV-IlJ and MXV-ll, 5.4 m (18 ft) (to-pin-to100pin connector).

BC21B-05

Modem cable from TU58 to EIA connector, 1.5 m (5 ft) (lO-pin-to-DB25-P
male).

TU58-K

Preformatted tape cartridges, available singly or in packs of five.

TUC-OI

Tape Drive Cleaning Kit.

ru58-DB

Rackmount installation kit for tabletop versions -EA, -EB, -VA.

TU58-EC

Accessory kit containing detachable line cord for 115 V. accessory assembly
hardware kit (70-16753-00), User Guide, Field Maintenance Print Set
(MPOI014).

TU58-ED

Accessory kit containing detachable line cords for 115 V and 230 V and fuse for
230 V, two cartridges, two I/O cables (BCI7A-18 and BCI7B-18), boot ROM
for MRII-EA, accessory assembly hardware kit (70-16753-00), User Guide,
Field Maintenance Print Set (MPOI014).

TU58-VB

Accessory kit containing dc power cable (70-17569-1C), I/O cable (70-177568IF), two cartridges, MXVI1-A2 boot ROM, User Guide, Configuration Guide,
Field Maintenance Print Set (MPOlO13), accessory assembly hardware kit (7016753-01).

17-00090-00

Line cord 250 V.

70-16753-00

Accessory assembly hardware kit with brackets for mounting TU58 tabletop
versions to flat surface.

70-16753-01

Accessory assembly hardware kit with brackets for mounting TU58 tabletop
versions below a flat surface.

23-126F3-O-O

Boot ROM for BDVl1.

MXVI1-A-2

Boot ROM for MXVII.

23-765A9-OO

Boot ROM for MRII-EA.

1.6 HARDWARE DOCUMENTATION ORDERING INFORMATION
The following TU58 DECtape II Tape Subsystem hardware manuals can be purchased from
DIGITAL's Accessory and Supplies Group.

Part No
EK-OTU58-UG
EK-OTU58-PS
EK-OTU58-TM
EK-OTU58-IP
MPOO747
MPOI014-00
MPO 10 13-00,
MPOI063

Title
TU58 DECtape II User Guide
TU58 DECtape II Pocket Service Guide
TU58 DECtape II Technical Manual (microfiche or paper)
TU58 DECtape II Illustrated Parts Breakdown
TU58-C Field Maintenance Print Set
TU58-E Field Maintenance Print Set
TU58-V Field Maintenance Print Set
TU58-D Field Maintenance Print Set

ORDERING
You can order supplies and accessories from one of the following addresses, according to your location.
Continental USA
Call 800-258-1710, or mail order to:
Digital Equipment Corporation
P.O. Box CS2008
Nashua, NH 03061
New Hampshire
Call 603-884-6660, or mail order to:
Digital Equipment Corporation
P.O. Box CS2008
Nashua, NH 03061
Alaska or Hawaii
Call 408-7344915, or mail order to:
Digital Equipment Corporation
632 Caribbean Drive
Sunnyvale, CA 94086
Canada
Call 800-267-6146, or mail order to:
Digital Equipment of Canada LTD.
P.O. Box 13000
Kanata, Ontario, Canada K2K 2A6
Au: A&SG Business Manager
Telex: 610-562-8732

1-9

1.7 DIGITAL REPAIR SERVICE
Digital Field Service offers a range of flexible service plans. Choose the one that is right for you.
ON SITE SERVICE offers the convenience of service at your site and insurance against unplanned repair
bills. For a small monthly fee you receive personal service from our Service Specialists. Within a few hours
the specialist is dispatched to your site with all the equipment and parts needed to give you fast and
dependable maintenance.
BASIC SERVICE offers full coverage from 8 a.m. to 5 p.m., Monday through Friday. Options are
available to extend your coverage to 12-, 16-, or 24-hour days, and to Saturdays, Sundays, and holidays.
DECsenice offers a premium on-site service that guarantees extra-fast response and nonstop remedial
maintenance. We don't leave until the problem is solved, which makes this service contract ideal for those
who need uninterrupted operations.
Under Basic Service and DECservice all parts, materials, and labor are covered in full.
CARRY -IN SERVICE offers fast, personalized response and the ability to plan your maintenance costs
for a smaller monthly fee than On-Site Service. When you bring your unit in to one of 160 Digital
Servicenters worldwide, factory~trained personnel repair your unit within two days (usually 24 hours). This
service is available on selected terminals and systems.
Digital Servicenters are open during normal business hours, Monday through Friday. Call one of the
following numbers for the location of the office nearest you.
DECmailer offers expert repair at a per use charge. This service is for users who have the technical
resources to troubleshoot, identify, and isolate the module causing the problem. You mail the faulty
module to our Customer Returns Center where the module is repaired and mailed back to you within five
days.
PER CALL SERVICE offers a maintenance program on a noncontractual, time-and-materials-cost basis.
This service is available with either On-Site or Carry-In service. It is appropriate for customers who have
the expertise to perform first-line maintenance, but may occasionally need in-depth support from Field
Service.
Per Call Service is also offered as s supplementary program for Basic Service customers who need
maintenance beyond their contracted coverage hours. There is no materials charge in this case.
On-Site Per Call Service is provided on a best effort basis, with a normal response time of two to
three days. It is available 24 hours a day, seven days a week.
Carry-In Per Call Service is available during normal business hours, with a two to three day
turnaround.
For more information on these Digital Service plans, prices, and special rates for volume customers, call
one of the following numbers for the location of the Digital Field Service office nearest you.
Digital International Field Service Information Numbers
U.S.A.
Canada
United Kingdom
Belgium
West Germany
Italy
Japan
France

Denmark
Spain
Finland
Holland
Switzerland
Sweden
Norway

1-(800)-554-3333
(800)-267-5251
(0256)-57122
(02)-242-6790
(089)-9591-6644
(02)-617-5381/2
(03)-989-7161
1-6873152
1-10

430-1005
91-7334370
90-423332
(01820)-34144
01-8105184
08-987350
2-256422

CHAPTER 1
OPERATION

Z.1 TU58-DA, -CA RACKMOUNT CONTROlS AND INDICATORS
%01.1 Front Panel
The front panel (Figure 2-1) has two slots for the tape cartridges and two tape motion indicators for the
drives. In addition, the decorative bezel has a small compartment that can store up to four cartridges
(six on the -CA) in their boxes.

%o1.ZRua .Indicator
Each tape drive has an indicator that lights to show 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 indicator is on.
Z.I.3 Application and Removal of Power
The TUS8-DA has a power switch on its backpanel, while the TUS8-CA does not. If an outlet is available on a system power controller, the TUS8 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 TU58 initializes itself, performs internal diagnostic tests, and then asks the
host for an acknowledgement before it settles down to wait for instructions. See Paragraph 3.2.2 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.

TAPE STORAGE
AREA

Figure 2-1

TU58-DA and -CA Rackmount Front Panel

2-1

1.1 TU58-EA, -ED CONTROlS AND INDICATORS
1.1.1 Front Panel
The front panel (Figure 2·2) has two slots for the tape cartridges and two tape motion indicators for the
drives.
1.1.1 Run Indicator
Each tape drive has an indicator that lights to show tape motion in that drive.
1.1.3 Application and Removal of Power
The TU58·EA and -ED versions have power switches on their back panels. If an outlet is available on a
system power controller, these versions may be plugged into the controller. Otherwise, they do not need
to be turned off. Their idling power consumption is less than 20 W.

power removal.
1.3 TU58-VA CONTROlS AND INDICATORS
1.3.1 Front Panel
The front panel (Figure 2-2) has two slots for the tape cartridges and two tape motion indicators for the
drives.
1.3.1 Run Indicator
Each tape drive has an indicator that lights to show tape motion in that drive.

RUN INDICATOR
DRIVEO

DRIVE 0

Figure 2-2 TU58-EA, -ED, and -VA Front Panel

2-2

2.3.3 Application and Removal of Power
The TU 58-VA requires + 5 V and + 12 V from the device to which it connects. See the electrical specifications in Paragraph 1.4.2 for power requirements of a controller board and two drives. The part number of dc power cable supplied with the TU 58-VA is 70-17569-1 C. See Chapter 4 for installation information.
When power is applied, the TUS8 initializes itself, performs internal diagnostic tests, and then asks the
host for an acknowledgement before it settles down to wait for instructions. See Paragraph 3.2.2 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.
2.4 TUS8 COMPONENTS CONTROLS AND INDICATORS
See Chapter 5 for installation and operation of optional features.
2.4.1 Application and Removal of Power
The TU58 may be supplied with power from a host system. It is ready for operation within one second
of voltage stabilization. It does not neep to 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 internal diagnostic tests, and then asks the
host for an acknowledgment before it settles down to wait for instructions. See Paragraph 3.2.2 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.S CARTRIDGE
2.5.1 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 2-3 illustrates the fit of the
cartridge into the drive chassis grooves.
2.5.2 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 (run indicator turns off) 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 is sent to the host if a command is interrupted by removal of a cartridge. The cartridge may be
left in the drive as long as needed.
2.5.3 Keeping Track of Cartridges
If the TUS8 is used in a non-file-structured system, the cartridge does not have an identifying number
or label recorded on the tape. If a cartridge is changed, the TUS8 does not know that a different cartridge was loaded; the operator must keep track of the contents of various cartridges.
2.5.4 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 2-4) is in the inner position (toward
the drive roller), it locks out the write circuitry.
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. The operator should be sure that system or program tapes are
backed up with copies before loading them into the TUS8 with their write protect tabs set to record.
2-3

....U71

Figure 2-3 Cartridge Loading

WRITE PROTECT TAB IN
PROTECT POSITION

MOVE TO LEFT TO PROTECT

Figure 2-4 Write Protect Tab

2-4

The write protect tab can be completely removed for long-term write protection. On the metal-base
cartridge, use a fingernail under the protruding end to lift the protect tab. 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
part way and then lift from the front. To replace it, drop it into its slot and press forward and down.

2.S.S Cartridge Storage and Care
Store cartridges in their cases, away from dust, heat, and 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 it is possible that a tape has 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.

2.6 MAINTENANCE
2.6.1 Head and Puck Oeanlng
After the first 20 hours of break-in runtime on each drive. clean the head and motor puck with a longhandled cotton applicator moistened with DIGITAL cleaning fluid (from cleaning kit TUC-Ol), 95 percent isopropyl alcohol, fluorocarbon TF, 113 or equivalent (Figure 2-5). Push the puck around with the
applicator to clean its entire surface. 'After the first cleaning, repeat the procedure after every 100
hours of runtime. 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 TU58.

2.6.2 Operator Trouble Isoladon
Table 2-1 lists potential problems and possible corrective actions and comments. (Some items are not
applicable to components.)

2.6.3 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 the 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.

w; ~ f£ :1
I

DRIVE PUCK

MICROSWITCHES

111

TAP~HEAD

Figure 2-5 View Into Tape Drive Cartridge Slot

2-5

Table 2-1

Operator Trouble Isolation

Symptom

Action/Comments

TU58 does not respond
to host

Ensure that the TU58-CA, -DA, -EA, or -EB is plugged into a live ac
socket (or proper dc source for -VA or components).

Check that the voltage selection switch is properly set.

Ensure that the fuse and power cord are intact and properly inserted.

Check that the baud rates and interface standards are the same for
both the TU58 and the host interface board (Paragraph 4.7).

If possible, observe the self-test indicator on the controller board.
Remove the bezel on the rackmount version. When power is applied,
the indicator should light for a half 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 indicator remains
off, there is some problem within the board 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. An open wire in the line from the host prevents the
indicator from coming on. Other causes require servicing.

TU58 does not write
(reads okay)

Read errors (some host
operating systems may
provide this or a
similar message)

TU58 sends motoNtopped
error messages

Check that the write protect tab is set correctly on the cartridge
(Figure 2-4).

The trouble may be in a drive. Try writing on the other drive. Any
problem except the write protect tab setting requires service.

Clean the head. Dirt and tape oxide buildup can cause errors.

The tape may contain errors that were written onto it. 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. A new cartridge with
format problems will produce the same error message. Try another
cartridge.

Motor or head is reaching end of life. Replace drive.

This indicates that a malfunction has occurred in the data 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.

2-6

CHAPTER 3
PROGRAMMING

3.1 GENERAL PRINCIPLES

The TU58 is controlled by a microprocessor that frees the host computer from device-related operations,
such as tape positioning and error retry. Only one high-level command to the microprocessor is necessary to
initiate a complex operation. The host and ru58 communicate via strings of one or more bytes called
packets. One brief packet can contain a message which completely describes a high-level command. The
handshaking sequences between host and TU58 as well as packet format are defined by the radial serial
protocol (RSP), or the modified radial serial protocol (MRSP), and were designed to be suitable for transmission by asynchronous interfaces.
3.1.1 Block Number, Byte Count, and Drive Number
The TU58 uses a drive number, block number, and byte count to write or read data. Figure 1-4 (Chapter 1)
shows the locations of blocks on the tape. If all of the desired data is contained within a single 512-byte
block, the byte count will be 512 or less. When the host asks for a particular block and a 512-or-Iess byte
count, the TU58 positions the specified drive (unit) at that block and transfers 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 reads 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, the MRSP, or in the ru58 firmware.
1.

A short routine called Newtape (Appendix B) 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 to proper operating tension levels.

A TU58 handler should check the success code (byte 3 of the RSP or MRSP end message) for
the presence of soft errors. This enables action to be taken before hard errors (permanent data
losses) occur.

3.2 RADIAL SERIAL PROTOCOL (RSP) AND MODIFIED RSP (MRSP)
3.2.1 Packets

All communication between the host and the TU58 is accomplished via sequences of bytes called packets.
There are two types of multi-byte packets: Control (Command) and Data. Either RSP or MRSP may be
selected using the command packet switch byte. In addition, there are three single-byte packets used to
manage protocol and control the state of the system: INIT, Continue, and XOFF.
Control (Command) - A Control packet is sent to the TU58 to initiate all operations. The packet
contains a message completely describing the operation to be performed. In the case of a read or
write operation, for example, the message includes the function to be performed, unit (drive) number, byte count and block number.
3-1

A special case of the Control packet, called an End packet, is sent from the TU58 to the host after
completion of an operation or on an error. The End packet includes the status of the completed or
aborted operation.
Data - The Data packet holds messages of between 1 and 128 bytes. This message is actually the
data transferred from or to the TU58 during a read or write operation. For transmissions of larger
than 128 bytes, the transfer is broken up and sent 128 bytes at a time.

INIT - This single-byte packet is sent to the TU58 to cause the power-up sequence. The TU58
returns Continue after completion, to indicate that the power-up sequence has occurred. When the
TU5S makes a protocol error or receives an invalid command, it reinitializes and sends INIT continuously to the host. When the host recognizes INIT, it sends Break to the TU58 to restore the
protocol.
Bootstrap - A flag byte saying Bootstrap (octal 10), followed by a byte containing a drive number,
causes the TU58 to read block 0 of the selected drive. It returns the 512 bytes without radial serial
packaging. This simplifies bootstrap operations. Bootstrap may be sent by the host instead of a
second INIT as part of the initialization process described below.
Continue - Before the host sends a Data packet to the TU58, it must wait until the TUS8 sends
Continue. This permits the TU58 to control the rate that data packets are sent to it.

XON - An alternate term for Continue.
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
TU58 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.)

3.2.1.1 Packet Usage - Position within the packet determines the meaning of each byte. All packets
begin with a flag byte, which announces the type of packet to follow. Flag byte numeric assignments
are as follows.

Flag Byte Value
Packet Type
Data
Control (Command)
INIT
Bootstrap
Continue
XON
XOFF

Octal
01
02
04
10
20
21
23

Binary
00001
00010
00100
01000
10000
10001
10011

(Bits 5 - 7 of the nag byte are reserved.)
Multiple-byte (Control and Data) packets also contain a byte count byte, message bytes, and two checksum bytes. The byte count byte is the number of message bytes in the packet. The two checksum bytes
are a 16-bit checksum. The checksum is formed by summing successive byte-pairs taken as 16-bit words
while adding any carry back into the sum (end-around carry), The flag and byte count bytes are included in the checksum. (See example in Appendix 8.)

3-2

3.2.% Break and Initialization
Break is a unique logic entity that can be interpreted by the TU58 and the host regardless of the state
of the protocol. This is the logical equivalent of a bus init or a master reset. Break is transmitted when
the serial line, which normally switches between two logic states called mark and space, is kept in the
space condition for at least one character time. This causes the TU58's UART to set its framing error
bit. The TU58 interprets the framing error as Break.

If communications break· down, due to any transient problem, the host may restore order by sending
Break and IN IT as outlined above. The faulty operations are cancelled, and the TU58 reinitializes itself, returns Continue, and waits for instructions.
With DIGITAL serial interfaces, the initialize sequence may be sent by the following sequence of operations. 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. This times Break to be one character time long.
The second character is discarded by the TU58controller. Next, send two INIT characters. The first is
discarded by the TU58. The TU58 responds to the second INIT by sending Continue. When Continue
has been received, the initialize sequence is complete and any command packet may follow.
3.2.3 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 follow.
Table 3-1 Command Packet Structure
Byte

Byte Contents

Flag = 0000 0010(028)
Message Byte Count = 0000 101 O( 128)

1
2
3
4
6
7
8
9
10
11

OpCode
Modifier
Unit Number
Switches
Sequence Number - Low
Sequence Number - High
Byte Count - Low
Byte Count - High
Block Number - Low
Block Number - High

12
13

Checksum - Low
Checksum - High

Flag

This byte is set to 00000010 to indicate that the packet is a
Command packet.

Message Byte Count

Number of bytes 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 summing
words with end-around carry.

3-3

The remaining bytes are defined below.
2

Op Code

Operation being commanded. (See Table 34 and Paragraph 3.3
for definitions.)

Modifier

Permits variations of commands.

4·

Unit Number

Selects drive 0 or I.

Switches

Selects maintenance mode and specifies RSP or MRSP.

6,7

Sequence Number

Always zero for TU58.

8,9

Byte Count

Number of bytes to be transferred by a read or write command.
Ignored by other commands.

10,11

Block Numbet

The block number to be used by commands requiring tape positioning.

3.1.3.1 Maintenance Mode - Setting bit 4 of the switches byte (byte 5) to I in a read command inhibits retries on data errors. Instead, the incorrect data is delivered to the host followed by an end packet.
The success code in the end packet indicates a hard dt~.ta error. Since data is transmitted in 128-byte
packets, a multiple packet read progresses normally until a checksum mismatch occurs. Then the bad
data packet is transmitted, followed by the end packet, and the operation terminates.
3.1.3.1 Special Address Mode - Setting the most significant bit of the modifier byte (byte 3) to 1
selects special address mode. In this mode all tape positioning operations are addressed by 128-byte
records (0-2047) instead of 512-byte blocks (0-511). Zero-fill in a write operation only fills out to a 128byte boundary in this mode. To translate between normal addressing and special addressing, multiply
the normal address by 4. The result is the address of the first I 28-byte record of the block. Add I, 2, or
3 to get to the next three 128-byte records.
3.1.4 Data Packets
3.1.4.1 Radial Serial Protocol- A data transfer operation uses three or more message packets. The first
packet is the command packet from host to the TU58. Next, the data is transferred in 128-byte packets in
either direction (as required by read or write). After all data is transferred, the TU58 sends an end packet.
If the TUS8 encounters a failure before all data has been transferred, it sends the end packet as soon as the
failure occurs.
The data packet is shown in Table 3-2. The flag byte is set to 0018. 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 assumed 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 TU58 to send the Continue flag 0208 before sending the next packet. Because the
host has enough buffer space, the TU58 does not wait for a Continue flag between message packets when it
sends back read data.
3.1.4.1 Modified Radial Serial Protocol- When the host does not have sufficient buffer space to accept
entire transactions at the hardware selected data transfer rate, modified radial serial protocol (MRSP) may
be specified using the command packet switch byte. Bit 3 of the switch byte is set to specify the MRSP. Bit
3 remains set until intentionally cleared or cleared during power up. A good practice is to set bit 3 in every
MRSP command packet.

MRSP is identical to RSP except during transmission to the host. When a command packet specifies
MRSP for the first time (that is, bit 3 of the switch byte was previously cleared or cleared during power
up), the ru58 will send one data or end packet byte (whichever occurs first). The subsequent bytes, up to
and including the last byte of the end packet, will not be transmitted until a Continue or an XON is
received from the host. To prevent a protocol error from occurring, it is necessary to transmit Continue or .
XON before transmitting any command packets. If a protocol error is detected, continuous INITs are sent
with the Continue handshake. If a bootstrap is being transmitted, however, no handshake is employed.
3.2.5 End Packets
The end packet is sent to the host by the ru58 after completion or termination of an operation or an error.
End packets are sent using RSP or MRSP as specified by the last command packet. The end packet is
shown in Table 3-3.
Table 3-1 Data Packets
Byt~

Byte Contents

Flag = 0000 0001
Byte Count = M

-----------------"

2
3

First Data Byte
Data

M
M+ 1

Data
Last Data Byte

-M+2
- - - - - - - - ChecksumL
-- - - - -- - ..

ChecksumH

M+3

Table 3-3 End Packet
Byte

Byte Contents

o
1

Flag - 0000 00 10
Byte Count = 0000 1010

3
4
5
6
7
8
9
10
11

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

12
13

ChecksumL
ChecksumH

--------------,..--2

- - - - - -- - - - - - - -

3-5

---,-

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

Op Code - 0100 0000 for end packet

Byte 3

Success Code
Octal
Decimal
0
0
= Normal success
1
1
= Success but with retries
377
-1
== Failed self test
-2
376
= Partial operation (end of
medium)
370
-8
Bad unit number
No cartridge
367
-9
365
-11
== Write protected
-17
357
- Data check error
340
-32
== Seek error (block not found)
337
-33
== Motor stopped
-48
320
- Bad opcode
-55
311
== Bad block number (> 511)

Byte 4

Unit Number 0 or 1 for drive number.

ByteS

AlwaysO.

Bytes 6,7

Sequence number - always 0 as in command packet.

Bytes 8,9

Actual byte count - number of bytes handled in transaction. In a <good operation, this is the same as the data byte count in the command packet.

Bytes 10,11

Summary Status
Byte 10
Bit 0

•

Bit 7
Byte 11
Bit 0
1
2
3
4

5
6
7

Reserved

Logic error
Motion error
Transfer error
Special condition (errors)

3.3 INSTRUcnON SET
The operation performed by the TU58 when it receives a Control (command) packet is determined by the
op code byte in the control packet message. Note that while any command can specify modified radial
serial protocol with the switch byte, the response will not be MRSP if a boot operation is being performed.
Instruction set op code byte assignments are listed in Table 3-4.
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.

3-6

Table 3-4 Instruction Set
OpCode

OpCode

Decimal

Octal

IDstruction Set

0
1
2
3

5
6

5
6
7
10
11
12
13 .

NOP
INIT
Read
Write
(Reserved)
Position
(Reserved)
Diagnose
Gctstatus
Set status
(Reserved)
(Reserved)

7
8
9
10
11

The following is a brief description and usage example of each.
<

OP CODE'O NOP
This instruction causes the TU58 to return an end packet. There are no modifiers to NOP. The NOP
packet is shown below.

BYTE

0
1
2
3
4
5
6
7
8
9

10
11

12
13

0000
0000

0000

0010
1010
0000

0000
0000

0000

0000
0000

0000

OOOX

0000

0000
0000
0000
0000
0000
0000

0000
0000
0000

0000
00IX
1010

FLAG
MESSAGE BYTE CNT
OPCODE
MODIFIER
UNIT NUMBER (IGNORED)
SWITCHES (NOT USED)
SEQ NO. (NOT USED)
SEQ NO. (NOT USED)
BYTE COUNT L
BYTE COUNT H
BLOCKNO.L
BLOCKNO.H
CHECKSUM.L
CHECKSUMH

NO DATA
INVOLVED
NO TAPE
POSITION

The TUS8 returns the following end packet.

0
1
2
3
4

S
6
7
8
9

0000
0000

0100
0000

0000
0000
0000
0000

0000
0000
0000
XXXX

12
13

XXXX

ooox

0010
1010
0000
0000
OOOX
0000
0000
0000
0000
0000
0000
XXXX
XXXX
XXXX

FLAG
MESSAGE BYTE CNT
OPCOPE .
SUCCESS CODE
UNIT (IGNORED)
NOT USED
SEQ.L
SEQ.H ....
. ACTUAL BYTE CNT L
ACTUAL BYTE CNT H
SUMMARY STATUS L
SUMMARY STATUS H
CHECKSUML
CHECKSUMH

3-7

NO DATA
INVOLVED

OP CODE 1 INIT
This instruction causes the TU58 controller to reset itself to· a ready state. No tape positioning results
from this operation. The command 'packet is tbe same as for NOP except for the op code and the resultant change to the low order checksum byte. The TU58 sends the same end packet as for NOP after
reinitializing itself. There are no modifiers to IN IT.
OP CODE 2 Read, and Read with Decreased Sensitivity
This instruction causes the TU58 to position the tape in the drive selected by Unit Number 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 is recognized by the host by the flag byte. The host sees a command flag (0000 0010) instead of
a data flag (0000 0001).
There are two modifiers to the read command. Setting the least significant bit of byte 3 to 1 causes the
TU58 to read the tape with decreased sensitivity in the read amplifier. This makes the read amplifier
miss data if any weak spots are present. Thus, if the TU58 can read error-free in this mode, the data is
healthy. The read transaction between TU58 and host is shown for 510 bytes (just under a full block) in
Figure 3-1. Setting the most significant bit of byte 3 to 1 selects special address mode. See Paragraphs
3.2.3.1 and 3.2.3.2.

HOST

TU58

COMMAND
PACKET
(READ 510 BYTESI

I
.. I
~ .

,,I

•
•

I
I
•
I
.. II
..

DATA
128 BYTES

DATA
12BBYTES

DATA
126 BYTES

END

I
I
I
I
I

_.378

Figure 3-1 Read C()mmand Packet Exchange' .
OP CODE 3 Write, and Write and Read Verify
This op code causes the TU58 to position the tape in the selected driveto 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 ina 512-byte tape block.

3-8

There are two modifiers pennitted with the write command. Setting the least significant bit of byte
3 to 1 causes the TU58 to write all of the data and then back up and read the data just written with
decreased sensitivity 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 - 17 (357 8 ) to indicate a hard read
error. Setting the most significant bit of byte 3 to 1 selects special address mode. See Paragraph
3.2.3.2.
.
.
The write operation 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 TU58 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 000 1
0000 from TU58 to host. The RSP write transaction for both write and write/verify operations is shown in
Figure 3·2. The MRSP write transaction for both write and write/verify operations is shown in Figure 3·3.

russ

HOST
COMMANO
PACKET
WRITE
620,
BYTES

CONTINUE

DATA
128 BYTES

TAPE POSITIONS
AND WRITES OATA
CONTINUE

OATA
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
108 BYTES

TAPE POSITIONS ANO WRITES
DATA. TU58 ZERD-FILLS REMAIN·
ING 404 BYTES OF BLOCK. IF WRITEI
VERIFY. TAPE REWINOS AND READS
BLOCKS JUST WRITTEN AND TESTS
CHECKSUMS.

ISUCCESSIFAILUR~
ENb
I

Figure 3-2 RSP Write Transaction

3·9

MAo2S77

HOST

CONTINUE

COMMAND
PACKET
WRITE
6108YTES

I
I

DATA
1288YTES

CONTINUE

•
DATA
1288YTES

II .

CONTINUE

TAPE POSITIONS
AND WRITES DATA
CONTINUE

..
DATA
1288YTES

TAPE POSITIONS
AND WRITES DATA
CONTINUE

I I ..

CONTINUE

•

CONTINUE

.. SEND "CONTI NUl!" HERE ONLY IF
THE FOLLOWING COMMAND PACKET
IS NOT THE FIRST COMMAND PACKET
AFTER SELECTING MRSP.

I
I ..
I
I I ..

CONTINUE

DATA
128 BYTES

TU58

TAPE POSITIONS
AND WRITES DATA
CONTINUE

II ..
I I ..

WHEN USING MRSP. AN END PACKET
TRANSFER REQUIRES ''CONTINUE'' OR
"X-ON" FROM THE HOST BEFORE EACH
REMAINING 8YTE

END
SUCCESS/FAILURE
148YTES
MA·10.a3

Figure 3·3 MRSP Write Transaction

3-10

OP CODE 4 (Resened)
OP CODE 5 Position
This command causes the TU58 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. See Paragraph 3.2.3.2.
OP CODE 6 (Reserved)
OP CODE 7 Diagnose
This command causes the TU58 to run its internal diagnostic program which tests the processor, ROM,
and RAM. Upon completion, TU58 sends an end packet with appropriate success code (0 = Pass, -1 =
Fail). Note that if the bootstrap hardware option is selected, boot information will be transmitted without
handshaking even if the switch byte specifies MRSP.
OP CODE 8 Get Status
This command is treated as a NOP. The TU58 returns an end packet.
OP CODE 9 Set Status
This command is treated as a NOP because TU58 status cannot be set from the host. The TU58 returns
an end packet.
OP CODE 10 (Resened)
OP CODE 11 (Resened)
3.4 PASCAL TUS8 HANDLER ALGORITHM DEFINmONS
The following collection of algorithms describes the basic functions required for using the TU58 in a
system. These algorithms are written in a pseudo-Pascal language and are therefore only designed to
illustrate the logic of operations involved in causing the TU58 to perform the intended function. Actual
software for a particular host computer may be written using these algorithms along with the program
examples found in Appendix C. The following is a list of the functions described.

tudiagnose - Constructs and sends the command packet causing the TU58 to execute its
built-in, self-test diagnostic. Returns the TU58 end packet success code as the result.

tuseek - Constructs and sends the command packet which causes the TU58 to position the
tape inserted in the specified drive to the specified block. Returns the'success code obtained
from the TU58 end packet as the result.

turead - Constructs and sends the command packet which causes the TU58 to.read data from
the tape in the specified drive into a buffer area. Returns the success code obtained from the
TU58 end packet as the result.

tuwrite - Constructs and sends the command packet which causes the TU58 to write data
from the buffer area specified to the specified TU58 tape unit. Returns the success code
obtained from the TU58 end packet as the result.

In addition to the above specific functions, algorithms for supporting routines are also provided. These
routines are shared by the TU58 function routines and are included for the sake of completeness.
Digital Equipment Corporation assumes no responsibility for the correctness of these algorithms, nor
offers corrections should errors be present. These algorithms may be copied for use on any computer
system by any suitable language implementation.

3-11

CONSTANTS

(Defines some interesting and useful constants )

{ Define single byte packet flags }
data
control
init
continue
xoff

1;
= 2;
= 4;
= 16;
= 19;
=

{ Define multi-byte packet opcodes }
read.opcode
write.opcode
positlon.opcode
diagnose.opcode
end.pack.opcode

= 2;

= 3;
= 5;

= 7;
= 64;

( Define initialization success codes )
success
failure

= 0;

= -127;

{ Define some useful sUbscript values }

= 0,
= 1;
= 21
= 4;
data.count.low = 8;
data.count.hiqh = 9;
command.block.low = 10;
command.block.hi9h = 11;
co~mand.flag

command.count
command.opcode

co~mand_unit

( Define length of command/data messaqes }
command.length
data.block

GLOBAL.VARIABLES

= 10;
= 128;
(Indicate quantities used by all functions }

slngle.byte.packet : byte;
( Note the variable length of the array defined below.
Its length is a function of the type of message to be
sent, i.e., N is the number of bytes contained in the
message )
multl.byte.packet : ARRAY[O •• N+31 OF byte;

CALLING.PARAMETERS { Parameters defined by the calling routines}
unit.number, block.number :INTEGER; { SpeCified unit/block}
no.bytes : INTEGER; ( Number of bytes in message )
buffer: ARRAY[l •• no.bytes] OF byte; ( Data/message space)

3-12

tudlagnose,

« This routine runs the TU58 self-test diagnostic routine }
BEGIN

« Construct and send the command pac~et

necessary to cause tne TU58 controller
to execute its self-test diagnostic.
Return the value of the success code
contained In the TU58 end packet ••

IF inltiallzeCdiagnose.opcode)=success THEN BEGIN
send.packet(packet, command.length+2),
tudiaqnose := qet.end.packet
END
ELSE
tudiagnose := failure
END, « tudiagnose •

tuseek (unit_number, block.number),

« Coristruct and send a command. p,cket which Indicates tne

TU58 should POSition the specified unit to the specified
block. This routine returns the succe~s code sent in
the TUS8 end packet ~s its result ••

BEGIN

IF Initiallze(posltion.opcod.)=success THEN 8EGIN

« Construct/send a command paCket •
packet [command.unltl := unit.number;
packet [command.block.lowl := 10W(block.number),
packet [command.block.hlgh] := highCbloCk.number),
send.packet(packet, command.lenQth);

« Conclude with an end packtt )

ELSE
END,

tuseek := get.end.packet,
END;
tUleek := failure,

« tUleele }

turead (unit.number, blocle~nUmber, buffer, no.bytes),

« Constuct and send the command packet required to read

'no.bytes' from the unit and block specified. Reads data
from the tape into a buffer space, returning the value of
the succels code contained in t~e TU58 end packet ••

BEGIN

IF initiallze(read.opcode)=success THEN BEGIN
( Construct comllland· packetr operators 'low', 'high'
return low byte, high byte respectivelY.
packet [command.unitl := unit.number,
packettcommand.block.lowl := 10W(block.numDer);
packet [command.block.highl :- hiqhCblock.number),
send.packetCpacket, command.lenQth);

3-13

( Get data output and stutf In buffer )

END
ELSE

If get_data_packet(buffer)=success THg~
turead := get.end_pac~et
ELSE turead := failure

turead := failure
END; { turead }
tuwrlte (unit.number, block.number, bufter, no.bytes);
( Construct and send a command packet specifying tne
unit and block for writing data. write the data from
the specified buffer area to t~e tape. Return the
success code obtained from the TUSS end packet as the
result.)
LOCAL.VARIABLES
count, data.count : INTEGER;
BEGIN
IF lnltlallze(wrlte.opcode)=success THEN BEGIN
( stuff parameters into command packet )
packet[comm'41nd.unltJ:= unlt.number;
packet[command.block.lowl := low(block.number);
packet (command.block.highl := hlgh(block.number);
send.packet(oacket, command.length);
{ If continue Is received, send data; 'qet.byte'
'put.byte'are Implementation-dependent function
calls }
data.count := no.bytes
wHILE qet.byte=contlnue THEN DO AEGIN
{ ~ake bloCkS maximum Of 128 bytes eacn }
count := mlnimum(data.count, data.block);
put_byte(count),
send_P8cKet(buffer[no_bytes-data_count+11,
count);
data.count := data.count - count
END:
{ In any event, try for an end packet at end }
tuwrlte := get_end_packet
END
ELSE

tuwrlte := failure
EhD; ( tuwrite )
Initialize (oP.code)1
( Initializes the TUSS by sending break characters on the
communication llne,.followed by the single byte pac~et
for INlT sent twice. The specified operation Is then
transmitted to the TUSS as either a single byte packet
or the first (command) byte of a multI-byte packet. }
BEGIN
( Set communication line control to BREAK }

3-14

( Delay multIple Character tIme to insure framlnq
error )
walt(n.Character.tlmeS)I
( Remove BREAL condltion from line •
reset.brealc.bi tI
{ Initialize command packet area )
packet [command.flaQ] := control;
packetlcommand.oPcodeJ := op.code;
( Send INIT flag to TUSe )
slngle.byte.packet 1= inlt;
Put.byte(sinqle.byte.paCket"
IF Qet.byte=eontlnue THEN Initialize := success
ELSE initialize := fallu'Tel
END, « lnitialize )
send.packet (buffer, nO.bytes);
( Send information contained in 'buffer' to TU58 )
LOCAL ... VAR !ABLES
1ndex, check.sum, cheCK.word : INTEGER,
BEGIN
( Must begin wlth CheCksum initialIzation )
cneck.sum := 0;
check.word 1= 0:
( Check for even/odd bytes, performing cnec~sum only
even1 the operator 'odd' returns a Boolean value
of TRU~ if the arqument 15 odd )
1f

FOR index := 1 TO no.bytes DO BEGIN
IF odd(lndex) THEN
check.word := bufferlindexl
ELSE BEGIN
check.word 1= butfer[indexl*256 + cheCk.word,
check.sum := check(check.sum, cnec~.wqrd)
END;
put.bvte(buffer[lndex])
END;
IF Odd(no.bytes) THEN
check.sum := cneck(check.sum, check.word>;
{ Now output cheCksum information; operators 'lOW',
'high' return low byte, hlg~ byte respectively}
put_byteClowCcheCK_sum»,
Put.byte(high(check.sum)
E~D'

( send.packet )

3-15

get.data.packet (buffer),
( Gets the data sent from the TU58 and stuffs it into
~buffer~ }
LOCAL.VARIABLES
index, checK.sum, data.count :

INTEGE~J

BEGIN
( Initlalize Checksum variables )
check.word := 0,
check.sum := get.byte,
( LOOk fdr valid data packet structure )
IF (check.sum<>data) THEN get.data.packet := failure
ELSE 8EGIN
( Get data packet from TU58, calculatlno
checksum al the butfer Is being filled )
data.count := get.byte;
check.sum I . check.sum + data.count*256;
FOR Index := 1 TO data.count DO BEGl~
buffer[index] := get.byte,
IF odd(index) THEN
check.word':. bUfter(lndex]
ELSE BEGIN
check.word := buffer(lndexl*256 + checkword,
Check.sum := check(CheCk.su~, check.word)
END
END

IF odd(data.count) TH~N
Check.SUM := Check(Check.sum, check.word),
( Make sure packet was not In error )
check.word := get.byte;
check.word := CheCK.word + get.byte*256J

END

IF check.word<>check.sum THF.N
get.data.packet := failure
ELSE get.data.packet := sut~ess

get.end.packet;
( Get. an end pacKet from the TUSS, returning success code
as result)
LOCAL.VARIABLES
index, Check.sum~ check.word I JNtEG£RJ,
BEGIN .
check.sum := get.byte,
« Look for valid command packet structure }
IF (check.sum<>command) OR (get.byte<>command.length)
OR (get.byte<>end) THEN get.end.packet := failure

3-16

ELSE BEGIN
{ Get success co~e from command packet )
get_end.packet := get.byte,
{ Now do the cheCKsum calcUlatlon )
checK.sum := checK(check.word, get.end.packet*256);
FOR Index := 1 TO 4 DO BEGIN
check.word := get.byte,
checK.word := check.word + get.byte*256,
check.sum := check(check.sum, check.word)
END;

« MaKe sure packet was not in error )

END,

END

cneck.word := get.byte,
check._ord := check.word + get.byt~*256'
IF check.word<>check.sum THEN
get.end.packet ,: failure
( get.end.packet )

check (argl, ar92),
( Computes the 16 bit checksum of argl and ar92, using endaround carry technique Of TUS8 )
BEGIN

« The function 'carry' returns a value of

1 if the sum of the arguments results in
a carry; a value Of 0 is returned otherwise )

Check := argl + arg2 + carry(argl,arq2)
END;

{ check}

{ End of algorithm definitions •

3-17

CHAPTER 4
INSTALLATION

4.1 INTRODUCfION
This chapter contains installation, configuration, and checkout procedures for all the versions of the
TU58 DECtape II (-DA, -CA, -EA, -EB, -VA components).
4.2 RACK INSTALLATION (-DA Version)
4.2.1 Rackmount
The TU58-DA mounts in 13.2 cm (5.1 in) of standard 48.3 em (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 DIGITAL 861 or
any power outlet.
4.2.2 Unpacking
The TU58-DA shipping carton contains the following items for rackmounting.

1
1

2
2
2
24
24
12
6
1

TU58"EB
Bezel
Mounting brackets
Support brackets
Support bracket extenders
Phillips trusshead screws 10-32 X 1/2 in
Internal lock washers
U-Nut retainers
Keplocknuts 10-32 X 3/8
Line cord (120 V)
Fuses (3/8 A and 3/4 A slow-blow)

4.2.3 Power Selection
Detachable line cords for 115 V and 230 V, and two fuses are supplied with the TU58-DA. The line
cord receptacle meets European IEC standards. A switch on the back of the tape drive rear panel selects 115 V or 230 V (Figure 4-1).

Set the voltage switch to the correct value using a small screwdriver.
Switch
Position
Left
Right

Voltage
115V
230 V

Range
90-128 Vrms
180 - 256 Vrms

CAUTION
If the TU58 is plugged into a 230 V circuit while set
for 115 V, it may be severely damaged.

4-1

FUSE POST

120/240V
SWITCH

INTERFACE CABLE
CONNECTOR

CABLE SHIELD
GROUND SCREW

120/240V
SWITCH

FUSE POST

INTERFACE CABLE CABLE SHIELD
CONNECTOR
GROUND SCREW

000

POWER
SWITCH

LINE CORD
RECEPTICAL

(A) NON·FCC COMPLIANT CONFIGURATION

(B) FCC COMPLIANT CONFIGURATION
MA~7e3().a3

Figure 4-1

TU58-DA Rear Panel

From the two fuses provided, select and instaH the proper fuse in the fuse post. To open the
fuse post, use a 3/16-inch blade type screwdriver: Press in the fuse post cap and turn it
counterclockwise. To close the fuse post, use the screwdriver to press in the cap and turn it
clockwise.

Voltage
115V
230V

Fuse
3/4 A slow-blow
3/8 A slow-blow

4.2.4 Removing Bottom Plates for Controller Board Configuration
The TU58 is shipped prewired for operation at 38.4K baud transmit and receive on RS-423. If a configuration change is necessary, the bottom plates must be removed in order to gain access to the controller board. Use the following procedure to remove the bottom plates. (See Paragraph 4.7 for configuration information.)
1.

Disconnect the power cord and interface cable from the rear panel of the TU58 (Figure 4-1).

Place the TU5S upside-down on a flat working surface so the rear panel faces you.

Remove the two Phillips head screws and lock washers from the front plate. Remove the
front plate, exposing the two tape drives.

Remove two Phillips head screws and lock washers from the bottom of the rear plate and one
flat Phillips head screw from the rear panel at the left side of the interface cable connector.
Remove the power supply assembly by lifting it out of the housing (with internal cables still
attached) and placing it rightside-up next to the TU5S.

4.2.5 Rackmounting Procedure
The following procedure enables one person to install the TU58-DA in the rack using a number 2 Phillips screwdriver.
1.

With the power cord and interface cable removed (Figure 4-1), carefully place the TU58-DA
upside-down on a flat working surface so the front of the device is facing you.

Remove the rubber feet if attached by removing the screws that hold them in place (Figure
4-1). Refer to Figure 4-2 and align the two support brackets on the bottom of the TU58-DA
so they are flush with the left side. Fasten down the right side of each support bracket with
two screws and two lock washers.
4-2

Figure 4-2 Installing Support Brackets

Fasten the mounting bracket to the left side of the TU58-DA with two screws and two lock
washers so the ball stud faces forward (bend in bracket toward center of TU58-DA). Install
the other mounting bracket in the same manner using two screws, two lock washers, and two
lock nuts to secure it to the support brackets (Figure 4-3).

Attach four U-Nut retainers (two per side) to the front vertical rails (Figure 4-4). Refer to
Figure 4-5 and position U-Nut retainers at the desired height for the TU58-DA.

Open the back of the rack. Attach four U-Nut retainers to the rear vertical rails (Figure 4-6).

If a non-DIGITAL rack is used, fasten the support bracket extenders to the rear vertical rails
with four screws, four lock washers, and four lock nuts. Use two per side in the top and bottom holes (Figure 4-7).

Turn the TU58-DA rightside-llpand while supporting it with one hand, place it into position
in the rack.

NOTE
Be sure the mounting brackets are to the inside of
the rear vertical raus.
8.

Fasten the mounting brackets to the front vertical rails with four screws and four lock washers (two per side in the top and bottom holes).

CAUTION
Install the two bottom screws first to avoid bending
the mounting earL
9.

For DIGITAL racks, fasten the mounting brackets to the rear vertical rails (Figure 4-6). For
non-DIGITAL racks, fasten the mounting brackets to the support bracket extenders (Figure
4-7).

10.

Attach the power cord and interface cable and connect to the appropriate device or receptacle. Close the back of the rack.

11.

Install the bezel by pushing into place over the ball studs (Figure 4-8).

4-3

Figure 4-3 Installing Mounting Brackets

MA-1472

Figure 4-4 Front Vertical Rail U-Nut Retainers

4-4

VERTICAL RAILS

2.22
(7/S:

1.59
(5181

8.04

2.88

(23181

(11181

1.59
(5/SI

4.78
(17181

L_
SALLSTUD

T
13.2

(5.191

____----4~

FRONT

1j.-·-----:r:3~51-----eoI·1 ~~1~~1

44.6
10----(17.151----01

I• c:=:::J c:::::J U
_ T
13.2
(5.191

·SUBJECT TO CHANGE

Io----~ 48.3 - - - - . . . I

(19.01

MEASUREMENTS ARE IN CENTIMETERS EXCEPT VALUES IN PARENTHESES
ARE IN INCHES.

Figure 4-5 Rackmounting the TU58·DA

4-5

REAR VERTICAL SUPPORT

MOUNTING BRACKET
MA·8417'

Figure 4-6 Rear Vertical Support U-Nut Retainers
REAR VERTICAL SUPPORT

MOUNTING
BRACKET

SUPPORT BRACKET
EXTENDER

Figure 4-7 Fastening Support Bracket Extenders

4-6

Figure 4-8 Installing the Bezel

4.3 'RACK INSTALLATION(-CA Venion)
4.3.1 Rackmount
The TVS8-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
DIGITAL 861 or any power outlet.
To get to the mounting holes, remove the bezel (Figure 4-9) by gripping it at the top and bottom with
both hands. Rotate it out from the bottom and lift it away. lethe 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

Metal bezels are heatry! " ,
If the rack requires them, install four V-Nut retainers at the holes spaced according to Figure 4·10. The

TVS8 is light enough for one person to install. Put the two bottom screws in first to avoid bending the
mounting ears.

4-7

-Figure 4-9 Bezel and Ball Stud

Four brackets and hardware are included with the TU58-CA to support the back end of the chassis in a
rack. Use the two long brackets for DIGITAL cabinets. The short brackets are extenders for the long
brackets used in non-DIGITAL cabinets~ Attach the long brackets to the chassis with the existing power supply screws, and attach to the side rails of the rack with the supplied clipnuts and screws. Hardware is also provided to fasten the extender to the long bracket if required. The bend on the long
bracket should point to the center of the rack while the bend on the extender should point to the outside
of the rack.
4.3.1 Power Selection for the Rack Version
Une cords for 110 V and 220 V and two fuses are supplied with theTU58-CA. The chassis power
receptacle meets European lEe standards. A switch on the back of the rackmount cabinet selects 110
Vor 220 V (Figure 4-11).

1. . Set the switch to the correct value using a small screwdriver.

CAUTION
If the unit is plugged into a 110 V circuit while set
for 110 V, it may be severely damaged.
2.

Install a fuse in the fuse post.

NOTE
A 3/8 Amp 'slow-blow fuse is required for 220 V, a
3/4 Amp 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.

4-8

FRONT VIEW

-T-

2.22

17181

TOP OF BEZEL

1.69

WIDE

(5/8)

8.04
(2318)

NARROW

2.88
(1118)

@
WIDE

1.59

WIDE

(5/81

4.78
(1718)

BOTTOM OF BEZEL

-~-

L -

t -_ _ _ _ _ _ _ 48•5 - - - - - - - - . /
(1B.31
0.95
(0.375)

FRONT OF BOX (BEZEL REMOVEDI

48.3
1ot--------(19.0)--------.I

-r-~--~------~~
13.2

1 ~--------~------------~ ~

(8. 81

FRONT

,..1·------'~~5)-----.l·1 ~~~~)

·---.:...-----.11

14-_ _ _ _ _ _ 44•5
(17.5)

•

rr~~~~'~uT

(18.0)~
·SUBJECT TO CHANGE

48.3
101-----.....;...-"--(19.0'----:...----.1
..

Figure 4--10 Rackmounting the TUS8-CA

4-9

CABLE SHIELD
GROUND SCREW

• _ . 110/220 V SWITCH

INTERFACE ..
CABLE
CONNECTOR

FUSE POST

m~ LINE CORD RECEPTACLE

Figure 4-11 TUS8-CA Rear Panel

4.3.3 Remofing Module from Chassis
Refer to Figure 4-12 and perform the following steps.
1.

Disconnect the power cord.

Remove the bezeL

Twist a coin or screwdriver in the gap between the retainer bar and the lip of the chassis. Lift
the bar out of the chassis and set it aside.

Pull the cage toward you a few inches and tum it to the right. Slide the module out an inch or
two and reach in at the back of the cage to remove the power and communication cables from
the module connectors. Remove the cage entirely from the chassis and put it on a stable work
surface.

Reach in again at the back of the cage and remove the drive cables from their connectors on
the module.

Now slide the module out of the cage.

CAUTION
Be careful around the tIain tachometer disk. It is easOy bent (and its edge is sharp). If the disk gets bent
without creasing, it might be straightened with
pliers. Alignment is not critieai, but it is better if the
disk does Dot I'iIb against the optical sensor block. If
it cannot be. aligned;· or if it is creased, it must be
replaced.
.
4.3.4 Reinstalling the Module
1.

With the connector edge facing into the cage, slide the module partially into the cage along
the card guides.

Install the drive cables onto their connectors. Note that the drive cables cross each other,
with the left drive cable going to the right connector (as you look into the open end of the
cage).

4-10

Figure 4-12 Installing Cage and Retainer Bar

Place the cage partially in the chassis and run the power and communication cables up to the
module onto their connectors.

Slide the module all the way into the cage and set the cage into the hooking tabs stamped
into the bottom of the chassis.

Align the retainer bar parallel to the floor of the chassis, with the spring on top. Engage the
two slots with the vertical sheet metal of the cage at the middle of the cutaways. Press each
end of the bar away and down, one at a time, so that the ends catch the lip of the chassis and
the bar holds the cage in place in the chassis. The module should sit in the cage with its edge
just clear of the retainer bar springs.

Replace the bezel and power cord.

4-11

4.4 INSTALLATION (-EA AND -ED VERSIONS)

The TU58-EA and -ED are tabletop units that require a minimum amount of space. Detachable line
cords for 115 V and 230 V and two fuses are supplied with the TU58-ED; only the 115 V cord and fuse
are supplied with the -EA. The cords are 6 ft long, enabling you to place the TU58 on a desk, tabletop,
or a convenient location within reach of a power outlet. See Paragraph 4.2.3 for the correct power selection information and Paragraph 4.2.4 for controller board configuration.
Tabletop Installation

4.4.1
1.

Disconnect the power cord and interface cable from the rear of the TU58 (Figure 4-1).

Place the TU58 upside-down on a flat working surface.

Install the four rubber feet usingthefour~ 1-.3cin -(1/2 in) Phillips head screws to secure
them to the bottom plates (Figure 4-13).

Tum the TU58 rightside-up and place iiin the desired location.

Connect the power cord, interface cable, and cable shield wire to the rear panel.

4.4.2 Solid Mounting Installation

Perform steps 1 and 2 as above.

Install the four mounting brackets (bend facing the side of the TUS8 housing) using the four
1.3 cm (I/2 in) Phillips head screws and lock washers to secure them to the bottom plates
(Figure 4-13).

Turn the TU58 rightside-up and place it in the desired location.

MA-6471

Figure 4-13

Mounting the TU58-EA and -ED

4-12

,
4.

Fasten the unit to the mounting surface using four screws through the holes of the mounting
bracket bends.
NOTE
The four screws needed to secure the unit to the
mounting surface are not supplied with the TUS8.

Connect the power cord, interface cable, and cable. shield wire to the rear panel.

4.5 INSTALLATION (-VA VERSION)
The TU5S-VA is a tabletop unit that requires a minimum amount of space and can be placed in a
convenient location within reach of a dc power source. (See Paragraph 1.4.2 for power requirements.)
In addition, the TU5S-VA can mount to the SBll (or BAll-VA) if so desired.
NOTE
If reconfigiJration Is necessaryt see Paragraph 4.2
before installing the TU58-VA.
4.5.1 Tabletop Installation
See Paragraph 4.4.1 for installation procedure.
4.5.2 Solid Mounting Installation
See Paragraph 4.4.2 .for installation procedure.
4.5.3 Mounting the TU58-VA to the SBll (or BAll-VA)

Attach the four rubber feet to the TU5S-VA as described in Paragraph 4.4.1, steps 1 through
4. (If solid mounting is desired, order hardware kit PN 70-16753-00).

Place the SBll (or BAll-VA) upside-down on a flat working surface.

Remove the rubber feet from the SBl1 (or BAl1-VA) if attached by removing the screws
securing them to the bottom. Fasten the four brackets to the bottom (bend on the outside
edge) using four screws and lock washers (Figure 4-14).

Position the SBll (or BAll-VA) rightside-up over the TU58-VA so the mounting brackets
line up with the holes on the side of the TU5S-VA. Fasten to the TU58-VA using four screws
and lock washers (Figure 4-14).

Referring to Figure 4-15, connect the interface cables and power cord to their respective locations.

4.6 COMPONENTS
Figures 4-16 and 4-17 provide the mounting dimensions for the circuit board and drive mechanism. The
drive has a 19 cm (7.5 in) cable which plugs into the board connector with the wires coming out of the
plug toward the center of the board. The plug is keyed to ensure proper orientation. The cartridge extends 1.60 cm (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
is somewhat larger than minimum, to allow easy insertion. The opening should be at least the dimensions of the cartridge, 1.3 cm (0.5 in) X S.1 cm (3.2 in), located not more than 0.53 cm (0.17 in) above
the bottom mounting surface (line A in Figure 4-16). The drive must be free to float on its mounting
screws, so bezels or panels must not touch the drive.

4-13

• 4 MOUNTING BRACKETS
AND SCREWS WITH
LOCKWASHERS FOR MOUNTING
TO BAllVA OR TO
HANG MOUNT

POWER

•
,

USE METAL BRACKETS WITH

10 32x 1/2 INCH SCR EWS FOR
r --L -.., SOLID
SCREWS WITH LOCKWASHERS FOR
MOUNTING
I

¥
I

MOUNTING TO THE TU5g.VA~

•

HARDWARE KIT
DEC PIN 70 1675300

USE RUBBER FEET
WITH 10-32 X 1/2 INCH
SCREWS FOR TABLE
TOP MOUNTING
• MOUNT BRACKETS TO BAllVA (SBl1) FIRST.

Figure 4-14 Mounting Choices for the TU58-VA

SERIAL LINE
UNIT (SLU)
GROUND
SCREW

. ;

TO DC SOURCE.
ON BAl1-VA.
TU58-VA
ORSB11

Figure 4-15

Interfacing the TUsS-VA

4-14

4.57

(1.8)

10.46

~--(4.12)----t
5.23
(2.06)

(3.812)
9.68

8.18
(3.22)

8.255

--r

(3.25)

1.80

(.71)

l3.50~

(1.38)DIA

8.88
1'1---(3.50)

Figure 4-16 Drive Outline Drawings

4-15

MEASUREMENTS ARE IN
CENTIMETERS EXCEPT .
VALUES IN PARENTHESES
ARE IN INCHES.

,.27.

(.501

24.85
1----------(9.791---------...
1--_ _ _ _ '4.76 _ _ _ _
(5.821

--t_1

.48

ilfl·'91
r-r-~~~-========~~-~-~-~~~
AMP HEADER #87633-6 AMP#87272-8
I
MATE: AMP #87159-6
DEC PT #12-13508-04
WITH #87027 CONTACTS MATE: AMP #87133-5
WITH #87124-1 CONTACTS
I
HEAT SINK:
3.0 (1.21 ABOVE
0.5(0.21 BELOW
SERIAL INTERFACE
1
12
. CONNECTOR
I
POWER
3 GNO CONNECTOR

13.18
(5.19)
12.32
(4.851
12:24
(4.821

,.....:::;DR:.::.;IV;..::E~O....,..-r_...,

5 +5
6 GNO

1--_ _ _ _ '4.64 _ _ _ _-e04
(5.77)

17.73

1--------(6.98)-----+1
r--_ _ _ _ _ _ _ _ 24.13 _ _ _ _ _ _ _ _.-!

(9.50)
24.72
1--------------(9.73)------+1
MEASUREMENTS ARE IN CENTIMETERS EXCEPT VALUES IN PARENTHESES ARE IN INCHES
MEASUREMENTS ARE ± .013 (.005) CENTER TO CENTER

Figure 4-17

MA·a370

Board Outline Drawings

The board should be mounted on a flat surface with 3 mm (4-40) hardware and 1 cm (3/8 in) standoffs.
Both the board and the drive may be mounted at any angle. For mounting the drives to a surface above
the drives, 1.80 cm (0.71 in) clearance is required; hole spacing is given in the outline drawings. For
mounting the drives to a surface below the drives, an 8.18 cm (3.22 in) X 8.89 cm (3.50 in) chassis
cutout is required, with the same mounting hole spacing.
CAUTION
The mounting surface for the drives must be nat
within 0.64 em (0.025 in).
Mountfug hardware is included with each drive. There is a shoulder screw, spring, and flat washer for
each of the four mounting holes. Figure 4-18 shows one assembly; in addition to the flatness specification for the mounting surface, there is a specification for the depth of the shoulder screw in the mounting surface. To prevent extra compression of the spring, the shoulder screw should meet the top of the
mounting surface. Any tapering of the mounting hole must be limited so that at the screw's diameter of
0.419 em (0.165 in) the edge of the shoulder is not more than 0.076 em (0.030 in) below surface.
4.7 INTERFACE STANDARDS SELECfION AND SETUP
The TU58 is shipped with factory-installed jumpers for a transmission rate of 38.4K baud and the RS423 unbalanced line interface. A variety of standards and rates may be selected by changing the jumpers on the controller board. 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.

4-16

THE MOUNTING
SURFACE FOR THE
DRIVES MUST BE FLAT
WITHIN 0.64 mm. (0.025 in.)
MOUNT ON 0.19mm.
(0.075 in.) MAX THICK·
NESS FLAT SURFACE
WITH 6-32 NUTS, ON
6-32 THREADED
SPACES, OR ON 6-32
THREADED INSERTS.
0.076mm. (.030 in.)
MAX PENETRATION
OF SHOULDER INTO
MOUNTING SURFACE.

FOUR ON EACH DRIVE

MA·S764f,

Figure 4-18 TU58 Drive Mounting Hardware

4.7.1 Selecting Interface Standards
The serial interface operates on full-duplex, asynchronous, 4-wire lines at rates from 150 baud to 38.4K
baud. 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 accordance
with EIA RS-422 balanced or RS-423 unbalanced signal standards. When set to RS-423, the TU58 is
compatible with devices complying with RS-232-C.
The TU58 is shipped prewired for operation at 38.4K baud transmit and receive on 1\S-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 4-19, 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.

4-17

Table 4-1

TU58 Module Connections

Wire-Wrap Pins
WWI
WW2
WW3
WW4
WW5
WW6
WW7
WW8
WW9
WWIO
WWll
WW12
WW13

150 Baud
300 Baud
600 Baud
1200 Baud
2400 Baud
4800 Baud
9600 Baud
19200 Baud
38400 Baud
UART Receive Clock Input
UART Transmit Clock Input
.
Auxiliary A (to interface connector pin I)·
Auxiliary B (to interface connector pin 10)·

WW14

Factory Test Point

WW15
WW16

Ground}

WWI7
WWI8
WW19
WW20
WW21
WW22
WW23 }
WW24

RS-423 Driver
RS-423 Common (Ground)
Transmit Line+
Transmit LineRS-422 Driver+
RS-422 DriverReceiver Series Resistor
(Jump for RS-422)

Boot

Connect together for auto-boot
on power-up.

Serial Interface Connector
J2 - 10
Auxiliary B
J2-9
Ground
J2 - 8
Receive Line +
J2 -7
Receive LineJ2-6
Key (no
connection)

J2-5
J2-4
J2-3
J2-2
J2-1

Ground
Transmit LineTransmit Line+
Ground
Auxiliary A

13,4-9
J3,4-10
J3,4-11
J3,4-12
13,4-13
J3,4-14
13,4-15
J3,4-16

LED
Head Shield Ground
Erase Retum
Erase 1
Erase 0
Head Retum
Head 0
Head 1

Power Input Connector

J1-1
Jl- 3
JI- 5
JI-6

+12V
Ground
+5V
Ground

DrfveCable
J3,4-1
J3,4-2
J3,4-3
J3,4-4
J3,4-5
J3,4-6
13,4-7
13,4-8

CartL
No Connection
Permit L
Signal Ground
Motor +
Motor+12V
Tachometer

• For optional use, such as timing signals from baud clocks.

4-18

1200
M

300
M

150
M

600

"' ' -

~"''''\~~

~('Q

,~"'~

CABLE
LENGTH

~(C'1!

30
M

100

15
M

3
M

FT
FT

300 600 lK

10K 20K 40K

DATA RATE IN BAUDS
RS·423
""2118

Figure 4-19 Data Rate and Cable Length for RS-423

4.7.2 Connecting Standards Jumpers
The jumper pins are standard 0.635 mm (0.025 in) wire-wrap posts which may be connected using 30
AWG wire and a hand tool. Other techniques that may be used include slip-on connectors, such as
DIG ITAL 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 420 illustrates the pin locations, and Figure 4-21 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 4-20. 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.
4.8 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 board should be on, indicating a functional processor.
4.8.1 Checkout of Interface
To address the serial interface device registers with the console (consult the system manuals for address
and codes), perform the following steps.

Set the transmit control status register to send Break to the TU58.

Remove the Break condition.

Transmit INIT: 04 (octal) to the TU58.

Transmit a second 04.

Examine the receive data buffer to find Continue: 20 (octal)
4-19

DIAGNOSTIC
LED

WW
TP +14
GND+

028

101 ~ BO.OT+f:

Id EJ

160+ WW
300+ 1
600+
1200+
2400+
4800+
9600+
19.2K+
38.4K+
RCV+CLK
XMIT+CLK
AUXA+
AUXB+ WW
13

232117-19
423 18-20
422
21-19
22-20
23-24

24
17
++++++++

MAo-23M

Figure 4-20 Interface Selection Jumper Pin Locations

4-20

38.4 KBAUD Rev + XMIT RS-423

o
o
o
o
o
o
o

c
c
c
c

(I.
o
o

ooooOObO

DC 0 DObbO

rnrnD

DTIDD
8800 BAUD RCV • XMIT RS-423

UA--2383

Figure 4-21

..........

Figure 4-22 TU58 Wiring (9600 Baud)

Factory Wiring

4.S.2. Configuring Interface Modules
This section lists the switch or jumper configurations recommended for DIGITAL's asynchronous serial
interface modules. These modules connect the LSI-II QBus or the PDP-II UNIBUS to the TU58's serial
interface. Each module is configured to run at the fastest speed possible (either 9600 or 38400 baud), at
the standard bus address (176500) and vector (300) for the TU58. For other speeds or addresses, read the
manual for the specific interface. And for TU58 configuration, see Figures 4-21 and 4-22. The interface
requirements are as follows.
EIA RS-423 voltage levels (RC232-C compatible)
Eight data bits
One start bit
One stop bit
No parity
Break enabled
NOTE
In the following tables, R means a jumper is
removed, and I means a jumper is inserted. ON and
OFF refer to the positions on board·mounted switch
packs. An X means the TUSS will work regardless
of the seating.

4-21

DLVll-A (M7940)
Jumper

Setting

A3
A4
A5
A6
A7
AS
A9
AIO
All
AI2

1
1
1
R
1
R
1
R
R
R

V3
V4
V5
V6
V7

I
1
I
R
R

FRO
FRt
FR2
FR3

1
1
I
R

NP
2SB
NB2
NBI
PEV
FEH
EIA

I
R
R
X
R
1

CLI
Cl2
Cl3
Cl4

X
X
X
X

Value

176500 (address)

300 (vector)

9600 (baud rate)

DLVtt-E (M8017)
Jumper

Setting

ValUe .

A3
A4
A5
A6
A7
AS
AIO
All
AI2

R
R
R
I
R
1
I
1
I

176500 (address)

4-22

DLVll·E (M8017) (Cont)
Jumper
V3
V4
V5
V6
V7
V8

Setting
R
R
R
I
I
R

RO
RI
R2
R3
TO
TI
T2
T3

I
R
R
R
X
X
X
X

BG
P

I
R
X
R
R
R
I
I
R
R
R
R
I
I
I
R
R
R
R

1
2
PB
C
CI
8
81
H
B
-B
-FD
·FR
R8
FB
M
MI

Value

300 (vector)

9600 '(baud rate)

DLVll-F (M8018)
Jumper

Setting

A3
A4
A5
A6
A7
A8
A9
AIO
All
AI2

R
R
R
I
R
I
R
I
I
I

Value

176500 (address)

4·23

DLVII-F (M8028) (Cont)
Jumper

Setting

Value

V3
V4
V5
V6
V7
V8

R
R
R

300 (vector)

RO
Rl
R2
R3
TO
Tl
T2
T3

I
I

R
I

R
R

R
X
X

2
PB

R
R
R

~
1

Cl
S
Sl
H

B
B
lA
2A
3A
4A
SA
IP

9600 (baud rate)

X
X

I
I

R
R
R
R
I

X
X
X
X
X
X

2P
3P
4P

X
X
X

M
Ml
MT

R
R
R

4-24

DLVlI-J (M8043)
Use channel 0 of the factory-configured module for the TU58 interface. Change the baud rate for channel

o from 9600 to 38400 by removing the jumper from 0 to N and connecting 0 to Z. Refer to Figure 4-23.
Channel 0 is now compatible with the factory-configured TU58 with address 176500 and vector 300.

CH2AND
CH3EIA
SELECTION

CHOAND
CHIEIA
SELECTION

RIO -

~f:r}c:H

sen
pe_

E~}

'----

;~}l
~ 1
P__
CH3

CHO
CHI COMMUNICATION LINE
CH2 PARAMETERS
~J-R - - C H 3

ree}

sen

pe_

AS'"
AI2
_._
AS .
.
AIO _ _
A,, _ _

ADDRESS AND
VECTOR JUMPERS
AO_
{ A7 e_

vaV7_

ABe_

3M
...........

C2e_

~~m
01)(

BREAK SELECTION
ICHANNEL3)

Figure 4-23 DLVll-J Factory Configuration Summary

4-25

MXVII-A (M8047)
Use channel 0 on factory-configured interface (address 176500 and vector 300). Refer to Figure 4-24
and Table 4-2

~I
eJ44
eJ43
eJ42
e J41

eJ40

1~.~~~I
J38

m eJ29
.J29i1
Li~J38
J35 .J27 I I·
J38

:J3D ..
J22J
"J21
eJ20
JIB
.J18
eJ17
eJ1B
18

.Jl•
• Jl

eJ12
eJl1
eJl0
eJl
eJ8

C!e
ee
J8J6 J4J3

.... 4 .....

.H..........
Figure 4-24 MXVll-A Jumper Locations

4-26

Table 4-2 MXVII-A Standard Factory Configuration
Wire-Wrap
From

Pins
To

Level

RAM bank 0

J30
J32
J31

J31
J33
J32

Ll
Ll
L2

SLU CHO,
address 177 560

J23
J24

JI8
J19

Ll
Ll

SLU CHI,
address 177560

J28
J26
J25
J27

JIO
Jl5
JI4
Jl3

L2
Ll
Ll
Ll

ROM bootstrap (TU58)

J37
J21
J34
J33
J29

J38
J22
J37
J39
Jl5

Ll
Ll
L2
L2
L2

J53
J54
J56
J54

J57
J52
J51
J55

Ll
Ll
Ll
L2

J59
J62
J60
J61
J59
J63

J6l
J64
J63
J62
J66
J65··

Ll
Ll
Ll
L2
L2
L2

J45
J46

J50
J48

LI
Ll

Bread generation
(Half option)

Crystal clock

J68

J67

Function

SLU
vectors

CHO(300)
CHI(60) .

SLU parameters
(eight data bits, no
parity bit, one stop
bit)

Baud
rates

CH0(38400)
CHI(9600)

4·27

DLtl-D (M7800 or M7800-YA)

Jumper

Setting

A3
A4
A5
A6
A7
A8
A9

I
I
I
R
I

AIO

V5
V6

V7
V8

176500 (address)

I
R
I
I
I

V3
V4

Value

300 (vector)

R
I

Baud rate switches
Position 8 for 9600 baud receive and transmit with speed group 4 crystal (4608 MHz).
NP
2SB
EPS
NB2
Nl

R
I
X

Jl
N2
J3
J4
J5
J6
J7
J8
J9
JI0
JlI

I
R

R
I

I
I
R

R
I

4-28

DLll-E (M7800)

Jumper

Setting

Value

A3
A4
AS
A6
A7
A8
A9
AIO

I
I
I
"R
I
R
I

176500 (address)

V3
V4
V5
V6
V7
V8

I
I
I

300 (vector)

R
R
I

Baud rate switches:
Position 8 for 9600 baud receive and transmit with speed group 4 crystal (4608 MHz),
NP
2SB
EPS
NBI
NB2
NI
JI
J2
J3
J4
J5
J6
J7
J8
J9
JI0
J 11

R
I

X
R
R
I
I

R
R

R
I
I
I
I

R
I

4-29

DLll-W (M7856)
(address 176500, vector 300, speed 9600 baud)

Switch Pack

Switch
Number

Position
Not used (Switch
placement unspecified)

1
2
3
4

5
6
7
8
3

On
On

orr
orr

6-10

2
3
4

5
6
7
8
9
10
5

orr
orr
On
orr
On
orr

X
X

1
2
3
4

5
6
7
8
9
10

orr
orr
On
orr
orr
X
X

orr
orr
On
orr
On
orr
On
On
On

orr

4-30

4.8.3 Checkout of Drive Command Function
I. Insert a tape cartridge into drive 0 (left side). (The TU58 should have sent Continue (208)
already.)
2.

Transmit the following string of octal numbers to the TU58. (Consult the programming chapter
for an explanation of this format.)

2
12
2

o
o

o
o
o
o
200
200

204
212
The TU58 should wind to the beginning of the tape and read about half of the tape. If it does not work,
see Table 2-1, under "TU5S does not respond to host."

4-31

CHAPTERS
OPTIONS

5.1 RUN INDICATOR
Each tape drive may have an LED indicator which lights to show 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 indicator is on.
5.1.1 Installation
The indicator (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 indicator. Splice the run indicator 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 board side of the wire (symbol arrow pointing away from pin 7, Figure 5-1). The indicator is available from DIGITAL (PN 11-10324), and wires with slip-on connectors are available to
join the indicator to the tach (cable number 70-16526) and to extend the board connector end to the
indicator at the front of the drive (cable numbet70-16525).

TO PIN 7

J3,J4
PIN 7
+12V

ADDED
LED

...---,

I
PINB-----....I
PIN 9 - - - - - - - - - '

Figure 5-1

Installation of Run Indicator

5-1

5.2 BOOT SWITCH
5.2.1 General
Special provision has been made for interfacing the TU58 to the LSI-ll ODT keyboard interpreter.
The TU58 is placed at the system console address and vector, permitting it to "type" in a program
using keyboard ODT. This means that a keyboard cannot be connected at the same time. This arrangement is useful in an unattended control system, where the TU58 can automatically load and start or
reload and restart an unsupervised process controller or similar application. The Boot switch allows a
manual reboot without powering down to cycle the automatic sequence.

NOTE
Boot mode does not work in any DIGITAL operating system environment.
5.2.2 Operation
.. ; .
When the boot switch is connected according to Paragraph 5.2.3, the TUS8 operates in the following
manner.
1.

On power-up, the TUS8 checks for the presence of the closed switch. It then delays one second and begins the boot procedure.

When the TUS8 is in the idle state, it monitors the Boot switch. Any switch contact openclose sequence causes a one-second delay (to allow for contact settling or to allow the host
processor to enter the halt mode), and then the ruS8 begins the boot procedure.

The boot procedure positions the tape in drive 0 to block 0, sends Break to the host, and transfers A~
CII characters from the tape to the host. A delay is inserted between characters to allow for the echo
from the LSI-It. If the character sent is ASCII 0 - 7, this delay is one character time at 9600 baud.
Any other character is interpreted as a control chatacter, and time is allowed for 15 characters of echo.
The TU58 exits the boot mode following the transfer of the terminating character ASCII G (147g) and
enters the idle state. Because of the timing requirement, only rates of 9600, 19.2, and 38.4K baud may
be used with boot.
5.2.3 Installation
The boot pin on the board (WW16) may be connected to ground through a normally closed momentary
action switch. Wires may be wire-wrapped. DIGITAL 915 patch-corded, or soldered 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.
The boot tape contents are formatted to appear to the LSI-II as output from a console (keyboard)
operating under the ODT keyboard interpreter.

5-2

APPENDIX A
roSS/PDP-II TOGGLE-IN BOOT

This boots drive 0 only.

1000/012701
1002/176500
1004/012702
1006/176504
1010/010100
1012/005212
1014/105712
1016/100376
1020/006300
1022/001005
1024/005012
1026/012700
1030/000004
1032/005761
1034/000002
1036/042700
1040/000020
1042/010062
1044/000002
1046/001362
1050/005003
1052/105711
1054/100376
1056/116123
1060/000002
1062/022703
1064/001000
1066/101371
1070/005007

A-I

APPENDIX B
RSP SEQUENCE

"NEWTAPE" RSP Seauence

Checksum Calculation Exa.ple

2
12
5

o
o
o
o
o
o
o

carrw> 1

SEEK TO
8LOCK 777

12
0
0
0
0
1

0
377

2
5
0
0

Octal
Addition

377

1
6

14
2
12
5

o
o
o
o
o
o

0000101000000010
0000000000000101
0000000000000000
0000000000000000
0000000000000000
0000000111111111

~
14
6

SEEK TO
BLOCK 0

7
1::!

B-1

Binar~

Addition

APPENDIXC
SAMPLE DEVICE HANDLERS

ccccccccccccccccccccccccccccccccccccccccccccccccccccccCCCCCCCCCCCCcccccccccccc
c
c
C

C
C

TTTTTTT U
T
U
T

T
T

U 5555555 88888
US
8
8
U
US
8
8
U
U 555555
88888
U
U
58
8
U
U
58
e
UUUUUUU 555555
~8888

FORTRA~

SUP P 0 R T

C
C
C

C
T
PACKAGE
C
T
C
C
C
.
C
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
C
C
C
C
C
C
C
C
C
C
C
C

Tne following program listing contains a compl~te TUS8 device
handler package _ritten entirely in PDP-It FORTRAN IV. When
used with the RT-!! FORtRAN IV compiler and object-time system,
it can be built into ROM/PROM/EPROM based LSI-1t microcomputer
applications.
The program implements four user-program callable entry points:
ierror = TUREAD( unit, bloCk, bUfter, bytecount )
Read "bytecount" bytes from the TU58 drive specified by
unit "unit" into the data area specified by "buffer",
starting at random-access bloc~ "bloc~" on the cartridge.

C
C
C
C
C

lerror

Write "bytecount" bytes from the data area specified by
"buffer" onto TUS8 drive "unit", starting at tne randomaccess blOCk noted by "bloCk".

C
C

C
C
C

C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C

= TUWRIT( unit, bloCk, buffer, bytecount )

lerror

= TUSEE~( unit, bioCk )
Position the TUS8 cartridge located In drive "unit" at
the random-access bloCk specified by "bloCk".

ierror

= TUOIAG( )
Run tne TU58 internal controller dlaanostlc function.

In all four cases, the functions return a standard set of error
COdes, as follows:
!error value

o
1

-I

-2
-8
-9

-11
-17

meaning Of error Code
t40rmal success
Success, but retries were required
TUS8 failed self-test (TUDIAG)
Partial operation (end-of-medlum encountered)
Invalid unit nU~ber was speCified
No cartridge is mounted in specified drive
Specified cartridge is _rite-protected (TUWRIT)
Data cheek error on cartridge

C-l

-32
-33

-48

-S5
-127

c
c
c
c
C
e
e
e
e
e
e

error (block not found)
Motor stooped (TUS8 hardware error)
Invalid operation code (error in tois progra~)
Invalid record number (bad block number passed)
Communications error between host and TUS8
See~

This software assumes that the TUS8 controller is interfaced
tnrough a OLV11, DLVI1-J, DLVI1-E, DLV1!-F, or MXV11 Interface
whicn has a receiver CSR address assignment of 176500(8).
The software operates the interface in a non-interrupt-driven
mode only for simplicity.
This program is neither licensed nor supported by Digital
Eguipment Corporation, and may be copied or modified for ule
on any computer system. Dlaltal assumes no responsibility for
its rellaollity on any hardware, Digital-supplied or otnerwise.

e
cccceCCCCCCCCccccccececccccccceeccceececccccecccccccecCcccccceCCCCCCCCCCCC
c

e
C

e
e

e
e
e

INTEGER FUNCTION Tudlag

Runs TUSS controller diagnostic function, returning success
cooe as function result.
IMPLICIT INTEGER (a-z)
Icmdpktl packet(6)

eO~~ON

Initialize a command packet wltn the DIAGNOSE operation code.
TUdiag = Init(7)
IF (Tudiag.ne.O) GOTO 100
Now transmit the paCket to the TUSS controller.
CALL Sndpkt(packet,12,O)

And ask for the results of t~e diagnostiC in tne end packet.

100

Tudlag
RETUMN
END

e
e
e

e
C

= Getend(O)

INTEGER FUNCTION Tuseek( unit, block )
Positions cartridge in "unit" to r~ndom-access blOCk specified
by "bloCk", returning the success code from tne TUSS controller
as tne function result.
IMPLICIT INTEGER (a-z)
COMMON IcmdPktl paeket(6)
Initialize a command packet with the POSITION operat1on code

Tuseek
Init(S)
IF (TUseek.ne.O) GOTO 100
paeket(3)
unit
packet(6) = block

C
C
C
C

C
100

Transmit the command to the TUSS controller
CALL SndP~t(packet,12,0)
And ask for the statuI of tne operation from the end packet
Tuseek
RETURN
END

= Getend(O)

C-2

INTEGER FUNCTION TureadC unit, block, bUffer, bytC"t )
C
C

C
C
C

C
C
C
10

Reads "by tent" bytes from th~ TUSB drive select~d by "unitInto the data area speCified by "buffer", starting at randomaccess bloCk "block" on the cartridge. ~eturns the success
code from the TUS8 controller as the function result.
IMPLICIT INTEGER ca-z)
BYTE bufferCbytcnt), bword(2)
COMMON Icmdpkt/"packet(6)
EQUIVALENC~ (lword,bword)
Build a READ command packet and send it to the TUS8 controll~r
Turead = Inlt(2)
IF CTuread.ne.O) GOTO 500
packet(3) = unit
packet(5) = by tent
packet(6) = olock
CALL Sndpkt(packet,12,0)
Index = 1
~ead

the next data packet from. the TUS8

chksum
Getbyt()
IF (chksum.ne."OOl) GOTO 400 !Proceed to 400 It not data paCket
detent = Getbyt()
chksum
chksum + datcnt'256
Odd
0
DO 100, l=l,datcnt
odd = .not.odd
IF (odd.eq.O) GO TO SO
bword(2) = 0
bwordCl) = Getbyt()
butferClndex) • bword(l)
GO TO 100
bword(2) = Getbyt()
dhksum
Check(chksum,lword)
buffer(index) = bword(2)
Index
Index + 1
IF (odd.ne.O) ChkSum = Check(chksum,lword)
bwordCl) = Getbyt()
bword(2) = GetbytC)
IF Cchksum.ne.lword) GOTO SOO
GO TO 10

50
100

C
C
C
400
500

=
=

Found paCket which Is not data packet; try for end packet
Turead
RETURN
END

= Getend(chksum)

INTEGER FUNCTION Tuwrlt( unit, block, bUffer, bytcnt )
C
C
C
C
C

C
C

writes -bytcnt" bytes from data area specified by "buffer"
to TUS8 drive "unit", starting at random-access bloCk "blOCk".
Returns success code from TUS8 controller as function result.
INPLICIT INTEGER (a-z)
BYTE buffer(bytcnt), bword(2)
COMMO~ Icmdpktl packet(6)
EQUIVALENCE (lwOrd,bword)
Construct a -RITE command packet and transmit it to the TUS8

Tuwrlt
Inlt(3)
IF (Tuwrlt.ne.O) GOTO 500
packet(3) = unit
packet(5)
by tent
packet(6)
block
C)LL 5ndpkt(packet,12,0)

=
=

datcnt
C

= bytcnt

Prepare to transmit a new data pack.t by checking for CONTINUE

C
C

flag

Getbyt()
IF (chksum.ne. M020) GOTO 400
!Proceed to 400 if not CONTINUE
CALL PutbytCM001)
ITransmit data packet flag
count
MinOCdatcnt,128)
l~ake packets maximum 128 bytes
CALL PutbytCcount)
10utput byte count for packet
CALL Sndpkt(bUfferCbytcnt-datcnt+l),count,count*256+ M001)
datcnt
datcnt • count
GO TO 10
chksu~

Received flag was not a CONTINUE.

400

500

Tu~rit

Try for lND packet.

= Getend(Chksum)

RETURN
END
INTEGER FUNCTIOP4 Check C i.,

)

e
e

e
e
C
e
e
C

Computes l&-blt checksum of I and " using end-around carry
technique for TU58. Sum Is returned as function value.
IMPLICIT INTEGER (a-z)
check

=I + 1

If neither Input ooerand has high-order bit set, no carry
15 poss1ble
IF ( (l.or.l).ge.O ) GOTO 200
If both Inputs have hiOh-order bit set, a carry is always
generated

IF ( (i.and.1).lt.0 ) GOTO 100
C

C
C
C

If only one has high-order bit set, then a carry occurred
only If the sum doe I not have Its h1gh-order bit set
IF ( check.lt.O ) GOTO 200

C
C

100
200

Perform end-around carry if required
check • Check + 1
RETURN
END
INTEGER FUNCTION Getbyt

Gets next byte from the serial interface connecting the
TUS8 controller to the hOlt machine.

C
I~PLICIT

C
C

INTEGER (a-z)

Wait for input character aVailable (DONE flag set)
IF ( (IpeekC"176500).and."200).eQ.0 ) GO TO 10

C
C

C
222

Get Character from data buffer and remove extraneous bits

Getbyt
IpeekC"176S02).and.255
WRITE(6,222)GETBYT
FORMATC· R·,03)
RE'l'URh
END

C-4

SUBROUTIHE Putbyt( outbyt )
8YTE OUTBYT
C
C
C
C
C
C
C
10
C
C
C

222

C
C
C

writes a byte to the serial interface connecting the TUS8
controller to the host machine.
IMPLICIT INTEGER (a-z)
Walt for output interface ready (DONE bit set)
IF ( (Ipeek(·176504).and.·200).eQ.0 ) GoTO 10
Transmit character by moving It to data buffer register
CALL Ipo~e(·176S06,outbyt)
WRITE(6,222)OUT8YT
FORMAT(' T',Oll
RETURN .
END
INTEGER FUNCTION Inlt( opcode )
Initializes TuSa controller for operations.
Returns 0 If properly initialized, -127 otherwise.
IMPLICIT INTEGER (a-z)
IcmdPktl packet(6)

CO~MON

C
C

Initialize command packet area with opcode specified
Inlt = 0
packet(l) • 10*256 + -002
packet(2) = opcode
packet(l)
0
packet(4) = 0
packet(s)
0
packet(6) = 0

=
=

C
C

C
C
C
C
C
10
C
C

C
C
C

C
C

C
SO

Loop to allow eight retries of entire initialization
procedure
DO 50, J=l,a
Set BREAK bit in output serial interface (XCSR)
CALL IPoke(-176S04,-OOOOOl)
Walt for BREAK to cause framing error in TUS8 by
transmitting eight ~UL characters under It
DO 10, 1=1,8
CALL Putoyt(-OOO)
Remove BREAK CO~ditlon on output interface
CALL IPoke(-176504,-OOOOOO)
Discard any (pOSSiDly erroneous) character in input buffer
idummy • Ipeek(-176502)
Output two INIT commands to TUsa controller
CALL putbyt(-004)
CALL Putbyt(-004)
wait for , cheCk for CONTINUE flag In response
IF ( Getbyt().eq.-020 ) GOTO 100
CONTINUE

~·5

C
C
100

C
C

c
C
e
c
e

C
C
SO
C
C
C
100
C

C
C

If no success after ei9ht retries, report error

Inlt
·127
RETURN
END
SUBROUTINE SndpktCbuffer,bytcnt,chkini)
Transmits a command or data pacKet to the TUS8 controller,
sending "bytcnt" bytes from "buffer", followed by the uPdated
checKsum. CheCksum is initialized from the "chkinl" argument.
IMPLICIT INTEGER (a-z)
BYTE buffer(bytcnt). bword(2)
EQUIVALENCE (iword,bword)
Chksum = chkini
odd = 0
Loop to transmit packet contents, one byte at a time
DO 100, i=l,bytcnt
odd = .not.odd
IF (odd.eq.O) GOTO 50
If an odd-numbered byte, remember It for checksum calculation
bword(2) = 0
bword(l) = buffer(l)
GOTO 100
Perform Checksum calCUlation for each byte pair on evennumbered byte

bword(2)
buffer(l)
chKsum : Check(ChKsum,lword)
In either case, output byte to Interface
CALL Putbyt(buffer(i»
IF (odd.ne.O) chksum = CheCk(chksum,lword)
Output computed checksum for packet
lword = chksum
CALL Putbyt(bword(l»
CALL Putbyt(bword(2»
RETU~h

END
INTEGER FUNCTION GetendCchklnl)
C

C
C
C

c
c
C
C
C

c
c

C
10

Reads an end paCket from the TUS8 controller, returning

as the functlon value the success code from the paCKet.
I~PLICIT INTEGER (a-z)
BYTE bword(2)
EQUIVALENCE (lword,bword)

chksum

= chklnl

If Input cnecksum 1s not zero, first byte of paCket has
already been read bY the caller. It Is the "chklnl" value.
IF (cnksum.ne.O) GOTO 10
chksum = Getbyt{}
Check for valid gNO paCket structure.
IF (chksum.ne."002) GOTO 500
IF (Getbyt().ne.l0) GO TO 500
IF (Getbyt().ne."100) GOTO 500

!MuSt have flaq = COMMANO
!Must have byte count
10
!Must nave opcode = END

C-6

C
C
C
C

C
C

If • valid packet Is found, read success code byte and
store It
Getend • Getbyt()
chklum • Check(10*256."102,Getend*256)
Read and dllcard remainder of paCket, updating checksum
DO 100, 1=1,4 bword(l)
Getbyt()
bword(2) • Getbyt()
chklum
Check(chksum,lword)

100
C

500
600

Read transmitted checksum and compare with computed value

=
=

bword(l)
Getbyt()
bword(2)
Getbyt()
IF (Iword.eq.chksum) GOTO 600
Indicate Checksum or transmllslon error
Getend = -127
RETURN
END
.TITLE

TU58

.IDENT

10.11

NON-INTERRUPT DRIYE~ TUS8 HANDLER

, The fol10wlno program listing contains a complete TUS8 device
, handler paCkage written In PDP-II MACRO assembly lanQuage.

,, The program implements four FORTRAN-callable entry points:
,,,
IERROR = TUREAD( UNIT, BLOCK, BUFFER, BYTF.COUNT )
Read "BYTECOUNT" bytes from the TUS8 drive speclflp.d by
,,
unit "UNIT" Into the data area speCified
"RUFFF.R",
Itartlng at random-access block "BLOCK" on the cartridge.
,, IERNOR = TUWRIT( UNIT, 8LOCK, BUFFER, BYTECOUNT )
Write "BYTECOUNT" bytes from the data area specified by
,, bloCk
"BUFFER" onto TUSS drive "UNIT", starting at the random-access
noted by "BLOCK".
,,
IENROR = TUSEEK( UNIT, BLOCK )
,,
POSition the TU58 cartridQe located in drive "UNIT" at the
,,
random-access bloCk specified by "BLOCk".
,,
IERROR = TUOIAG( )
,,
Run the TUS8 Internal controller diagnostiC function.
,
, In all cases, the functions return a standard set of status
COdes, as follows:
,,,
NEANING OF STATUS
IERROR VALUa
,,
o
NormU success
success, but retries were required
,,
TUSe failed self-test (TUDIAG)
-1
partial operation (end-of-mediu_ encountered)
-2
,,
Invalid unit number was specified
NO eartrldQe Is mounted In speelfled drive
-9
,,
Specified cartridge Is write-protected (TUwRIT)
-11
Data check error on cartrldae
-17
Seek error (block not found)
,
stopped (TUS8 nardware error)
-33
I

COO~

-8

-32

~otor

C-7

Invalid operation code (error In this progra~)
Invali~ record nu~ber (bad block number passed)
Communications error between host and TUSS

-48

-55
-127

1
;
;

; This software assumes that the TUS8 controller is interfaced
; thrOugh a OLV11, DLVI1-J, DLVI1-E, OLVI1-F, or MXV11 interface
which has a receiver CSR address assiQnment of 176500(8). These
, SUbroutines were wr1tten w1th a goal of readability: time and
: space performances are not optimal.
;

,
,
,
;
;

This program 1s neither liscensed nor supported by DlGITAL
Equipment Corporat1on, and may be copied or modified for use
on any computer system. 01qital assumes no responsib1l1ty
for its reliability on any hardware, Digital-supplied or
otherwise.

;;

.SBTTL

Symbol Oefinit1ons and Data Area

Oefine packet flag byte codes

F.OATA
F.CTRL
F.INIT
F.CON!

F.XOFF

=
=
=
=
=

1
2

, Control
Data packet
packet
:

20
23

;

INIT pac\ct'!'t
CONTINUE packet
XOFF packet

: Define Control packet op-codes

O.READ
O.wPIT
O.POS
O.OIAG
O.lHD

=
=
=
=
=

2
3
5
7

100

perform read operat1on
perform wr1te operat1on
perform seek operation
perform self-test
packet is an End packet

Def1ne controller 1nterface address assignment
DLRCSR
DLRBUF
DLXCSR
DLXBUF

=
=
=
=

176500
OLRCSR+2
DLRCSR+4
DLRCSR+6

, Macro to send a cyte to TU58
;

LAB:

.MACRO
T518
BPL
MOVS
.ENDM

PUTeYT ARG, ?LAB
Ol'DLXCSR
LA8
ARG, UDLXi3i.1F
PUTBYT

; Macro to wait for a byte from TU58
; NOTE: If ARG Is a reg1ster, the par1ty bit w1ll be s1gn-extended
into the high-byte of the register.

LAB:

.MACRO
TSTB

GETSYT ARG, ?LAB
UDLRC5R

BPL·

LAB

MOVE!
il'DLRfHIF, ARG
.ENDM GETBYT
, Data area
.PSECT

USERSO

Rw, D, LCL, REL, CON

, Area used to build Control paCkets
;

PACKET: .BYTE
• WORD

F.CTRL, 10.

, Control paCket, length = 10 •

0, 0, 0, 0, 0

; Word used to collect byte-pairs for 16-bit cheCksum calculation

e-8

110RD:

.BLKW

code follows
,1 Pure (ROM-able)
.PSECT USERSI
I, LCL, REL, CON
R~,

.SBTTL

TURF-AD

Read Data From TU58

1+
1 TUREAD
I

; Description:
,
see module heading

,, Inputs:
,
1
,
,
,
,
1

RS points to a five word standard FORTRlh argument b10c~
O(RS)
4
2(R5) • address of unit number byte
4(R5)
address of block number word
6(R5) = address of callers input buffer
8.(RS)
address Of bytecount word

=
=
=

; Outputs:
,
RO

TUREAD::

t6-~lt

CALL
TSI
SNE

status code

the TU58
If error occured,
return error to c~ller
I~itlallz~

I~If

RO
50S

; auild a control packet
MOVS
MOVS

MOV
MOV

'O.READ, PACKET+2
PACKET+4

~2(R5),
~8.(R5),
~4(R5),

PAC~ET+8.

PACKET+I0.

packet to the TU58
,, Send the Control'PACKET,
RO
MOV
MOV
CLR
CALL

tt2., Rt
R2
SNOPKT

operatton is "RElO"
store unit number
store byte count
store bloc~ number

, PO points to packet
, R1
number of bytes to send
, P2
init!al chec~sum
send the Control packet

=
=

more Data paCkets from TUSS, followed by an End packet.
,: ReceiveMOVzero oro(R5),
111
Rt = address of callers buffer
I

get flag byte from TU58
If not a Data paCket,
, cheCk for End packet
8NE
90'
: oet byte count from TU58
GETBYT 112
, char hi-byte
SIC
'''C<377>, R2
SIiIAB
; form Initial cnec~sum in RO
112
815
R2, RO
I RO
current checksum
SWAB
112
; restore byte count
R3 Is even/Odd byte flip-flop
R3
CL~
I Re ce i v e all ch ar ac te rs 1 n th e Da ta pac ke t, u Pd at In 9 ch ec ks um a s
, each pair of Characters 15 received.
5S:

GETBYT
CMPB

110

RO,

U·.DAT~

10.:

20S:

COM
BEQ
eLR
G!TBYT
MOVa

R3
20$

NOIID
WORD
WORD, (R1)+

30.

G!TBYT
ADD
lOC

wOIlO+l
wORD, RO

MOV8

110

WORD+t, (Rl )+

flip flaq
,, branch
If second character of pair
build Character pair
,, store
with next data character
data byte In callers buffer
;

second byte of pair
, qet
update cnecksum
end-around carry
, with
store data byte in callers buffer
;

C-9

30$:

SOB

R2, lOS

TST
packet,

loop until byte count is zero

; If odd number of data bytes In

;
SEQ

40$

ADD
ADC

,, Receive
40$:

wORD, RO

checlcsu~

from TU58 and compare to computed value

CMP

"'ORO
WORD+l
wORD, RO

SEQ

GEnU

GETBYT

Checksum error.

: finisn checksum

get

16~bit

checksum

compare with computed cheCKsum
if the same, get next Data packet

Return error COde.

;

50$:

MOV
RETURN

set function value to error code
and return to caller

'-127., RO

, A paCket was received from the TUS9 that was not a Data paCket.
, Check to see that it is an End Packet.
;
90$:

cheCK End paCket and return to

JMP

;caller
;

.S BTTL

TU WR IT

Send oat a to T Us 8

1+
TUWRlT
I Descr1ption:

;

See module heading

, Inputs:R5 = address ot a five word standard FORTRAN argument block
0(R5)

=4
=
=
=

2(R5)
address of unit number byte
4(R5) • address of block number word
6(R5)
address of output buffer
B.(RS)
address of bytecount word

,,
;
;

, Outputs:

RO = 16-bit status code

,-;
TUWRIT::

CALL
TS7

IN IT
RO

if unsucceSSful,

SNE

99$

return to caller

initialize the TU58

Suild a Control packet to send to the TU58.
,",OVB
MOV~

MOV

'O.WRIT, PACKET+2

PACKET+4
fa.(RS), PACKET+8.
~4(R5), PACKET+l0.
~2(R5),

OD-code 1s "WRITE"
set unit number
set byte count
set blOCk nu~ber

, Send the Control paCket to the TU59.
;

MOV
MOV
CLR
CALL

'PACK!'.:T,
#12., Rl
R2
SNDPKT

TIl 0 V

@B.(R5), R3

MOV

6(R5), 115

RO = address of packet
Rl = number ot bytes to send
R2
1nltial checksum
send the paoket

=
=

R3
number of bytes left to send
R5 = adoress Of callers data nut fer

C-IO

, Send one or more Data packets to the TUSe.
10$:

GETBYT
CMPB
SNE
PUTBYT

flO

RO, ,F.CONT

90$

'F.DATA
1128., R4

,,
, to send,CMf
MOV
to send

R3, R4

get a byte from TU58
if not CONTINUE,
check for End packet
send Data packet flag
assume 128 or more bytes left

; if less than 128. bytes left

BHIS
IIOV
20S:

20S

to actual number left
send byte count
RO = address of packet to send
Rl = length of packet

fil, !/4
1-14

PUTBXT

RESET F4

RS, MO
R4, Rl
R4, R2
R2
,r.DATA, R2
SNDPKT
R4, R3
R4, RS

MOV
MOV
MOV

SitAe
ADD
CALL
SUB
ADO
8R

10$

,
I

R2
initial checksum
send the packet to fU58
update number o~ bytes left to sene!
update data buffer pointer
~ait for aCknowledgment from TUS8

; A byte was rece1ved from the TU5~ that was not a CONTINUE.
, See If the paCket 15 an End packet.

90$:
99S:

CALL
RETURN

GETENO

.S8TTL

TUSEEK

return to caller
Posl tion the TUS8

I TUSEEK

; Description:
;

See module heading

; Inputs:
;
RS
address of three word standard FORTRAN arqument block
I
O(RS)
2
;
2(RS)
address of unit number byte
,
4(RS) = address of blOCk number word

=
=

1 Outputs:

;

= 16-b1t status code

TUSEEK::

CUL
TST

Sr.E

99S

INIT

initialize the TUSS
if in1tialization failed,
return error to caller

; BUild Control packet to send to fUSe.
1

,",ove

Move
MOV

,Q.POS, PACKF.T+2
~2(RS), PACKET+4
~4(R5), PACKET+I0.

set op-code
set unit number
set bloCk number

send the Control packet to the TU58.
MOV
MOV
CLR
CALL

'PACKET, RO
112., 1H

R2
SNDPKT

~O points to packet
P2
lenqth of P!Cket
R2
initial checksu~
send the packet

=
=

Get an End packet from the TU58 and return to caller.
CLR
CALL
99$:

RETUR~

RO
GETEND

1ndicate no byte pre-read
return to caller

C-ll

·saTTL

TUDUG

Run TU58 Local Diagnostic

,, TUDUG
,

I
I
I

O~script1on:

S~e

mOdul~

h~adlnq

Inputs:
none

, Outputs:
,
RO II: 16-blt status code

TDOUG: :

CALL
TST
BN!

INIT
RO

Initialize the TU58
, If Initialization failed,
, return error code to caller

998

packet.
,, Build Control
Mova
'O.DIAG, PACKET+2
; send

•

t~e

, set op-code

Control packet to the TU58.

MOV

MOV
CLR
CALL

'PACKET, RO
112., R1
R2
SNDPKT

of packet
,, HIR2RO = address
length of packet
initial checksum
, send the
packet
;

II:

Receive an t:nd packet and return status code to caller.
;
99S:

CLR
CALL
RETURN

RO
GETEND

.S8rTL

INIT

, in~icat. no byte pre-read
, get the €nd packet
: return to caller
Initialize the TU58

,,, INIT
,, Description:
INIT is called by TUREAD, TUWRIT, TUSE!K, and TUDIAG
to initialize the TU58 to Its power-up state.
This is
by causing a fram1ng
In
TUS8,
,,,
followed by sending two INIT
to the TU58.
,, Inputs:The TUS8 should reply with a CONTINUE packet.
don~

~rror

th~

pack~ts

,,, outputs:
RO = 16-blt status code
,-,
non~

!HIT:

CLR
MOV

,,lOS:Send BREAk.
MOV
208:

MOV
PUTSYT
SOB
CLf!
TSTB

RO
.8., Rl

II, UDLXCSR
18., R2

a.sum~

;

r~try

success
eight times before failure

,, start nullS
sending a break
for 8 Character t1mes
s~nd

.,0

R2, 20$
UDLXCSR
.. OLRBUF

;

stop s~ndlng tne break
any extran~oUI input byte

remov~

C-12

I
I

Send two INIT paekets.
PUTBYT
PUTRYT

, send two INIT paekets

,'.INIT
IF .UllT

TU58 sent a Continue paeket
, see if GUBYT
R2
I

CMPS
BE-Q
SOB

R2, .... CO~T
99.
Rl, lOS

, get a byte fro. TUS8
If CONT1NUE ~ac~et,
r~turn to ealler
, else retry

Return error status to caller.
,: Retry falled.
MOV
9981

RETURN
.SBffL

.-127., RO

SNDPKT

Send a packet to TUS8

I SNDPKT
I

,, Description
SNDPKT is called by TUREAD, IUWRIT, TUSEEK, and TUDIAG to
send a mUlti-byte packet (either Control or Data) to the TUS8.
SNDPKT will also compute the packets checksum and send the
,,
checksum to the TU58.
, Inputsl address of bytes to send
;

;

I
I

RO
Rl
R2

= number of bytes to send
= the Initial checksum (non-zero If part of the packet has
= already been sent)

,,
, Outputs:
,
,- None
SMDPKt':

CLA

, make oddleven byte fllp-flop

-(SP)

to TUS8. Update 16-blt Checksum after eaeh byte palr.
,, Send bytes
, flip
oddleven flaq
COM
IOU
BEQ
branch if second byte of pair
, set up byte pair word
WORD
CLF<
(RO),
with first byte of pair
MOVe
BA
lOS
,, Update
s·tore second byte of pair
MOve
WORD+l
2081
cnecksum
WORD, R2
ADD
,, with end-around
carry
ADC
R2
send tne data byte
PUTBYT (ROH
loop until byte count is Zero
SOB
Rl, lOS
(SP)

20s

ilOilO

;

(RO),

30$1

40$1

TST
BEQ
AOD
ADC
PUTBYT
SwAB
PUTBYT
RETURN
.SBTTL

(SPH
40.

WORD, R2

R2
R2
R2
GEftND

I if odd number of data bytes,

update computed cheeksum
send 16-blt eheeksum
return to ealler
Cheek for End PaCket

,, G!TEND
,, Description.
GETEND 15 called by TURElD, TUWRIT, TUSEEK, and TUDIAG to accept
an End Control paeket from the TU58. GETENO
that the
I

v~rifles

C-13

,
,

received packet is indeed an End packet, and that the checksum
word in the packet equals the computed checksum.

, Inputs:
,
RO

= a byte already read by the caller or zero

, Outputs.
1
RO

= 16-bit status code

I·

GETEND:
, If flao byte was not pre-read by caller, read it now.
I
TSTB

BNE
GE'l'Bn

RO
lOS
RO

1£ not pre-read,

read it-

IOU
that the packet comlnQ trom the
Is Indeed an End Control packet.
,, Verify ClifPS
RO, .r.CTRL
check Control paCl<et
TUSS

aNE

G£TeYT

C"P8
ShE

GUBY!CfilP8
BNE
GETSYT
BIC
MOV
S"AS
ADD
ADC

908

RO
RO, UO.

with lenQth

908

RO, to.END
908

RO
,AC<377>, RO
RO, Rl
AI

'10.*256.+0.ENO+F.CTRL,
Rl

; and oP-code = End

success code
, qet
clear hi-byte
I

16-blt cheCksum In Rl
,Rl form
form 16-blt cheCksum
;

from bytes already received

,, Receive and ignore rest Of End packet, updatlnq
20$1

MOV
G!TSYT
GETBYT

ADD
ADC
S08
I

= 10.

cnecksu~.

14, R2
wORD
.ORD+l
WORD, Rl

Rl
R2, 20$

, lOOP four times to qet 8. bytes

Receive Checksum transmitted from TUS8 and compare with computed c-hecksum.

GET8YT
CMP

WORD
WORO+l
WORD, Rl

8EQ

100.

G£TaYT

I Return error code for transmission error.
I

908:
1001:

Mova

MDVB
RETURN

,-127., RO
RO, RO

, return status .s 16-blt value
; return to caller

.END

C-14

APPENDIXD
CARTRIDGE REPAIR

D.l INTRODUCTION
Under unusual circumstances of controller failure or cartridge mishandling, the tape might come free
of the hub. The tape 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 are given here to help
the user prevent the loss of important data. They are not a 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 number
1 Phillips head screwdriver and a small probe (a straightened paper clip can be used). Tweezers are
helpful.

NOTE
Keep magnetized tools away from the bulk of the
tape and do not touch the tape surface except at tbe
ends because fingerprints cause errors. (If staples or
paper clips stick to a tool, it is magnetized.)
D.2

METAL-BASE CARTRIDGE
1.

Open the cartridge by removing the four baseplate Phillips head screws (Figure D-1) and set
it upright on the work surface with the cover still on.

000 @

MA·2361

Figure D-l

Baseplate Screw Locations

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.
A spring is in the bottom of the gate. (Figure 0-3).
3.

Thread the end of the tape around the tape guides (Figure D-2).
ELASTOMER
BELT

SUPPLY
HUB
TAKE-UP
HUB

-+--+--1

TAPE GUIDE
TAPE
GUIDE
DRIVE
ROLLER

MA-2312

Figure 0-2 Threading the Metal-Base Cartridge

Moisten the end of the tape with water to get it to stick to the hub.

With a small amount of slack at the 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 keeps it feeding straight into the hub.

Continue to wind. Watch for the loose ends 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 drive roller fixed, and rotate the supply hub to take up the slack.

Continue winding the tape about 20 turns before reassembling.

10.

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 D-3.

11.

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.

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 spring down. It will clear its holding slot and snap into position, closing the gate.

0-2

MA-23&8

Figure 0-3 Head Gate and Spring

13.

Carefully lower the cartridge cover into place and reinstall the screws.

0.3 PLASTIC-BASE CARTRIDGE
Open the plastic-base cartridge case by removing the four baseplate Phillips head screws (Figure D-l).
Carefully remove the top.
0.3.1 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.

To 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.

Remove the floating roller (Figure D-4).

ELASTOMER+-----..
BELT

MA·2355

Figure 0-4 Stretch the Belt with the Floating Roller

0-3

Rearrange the elastomer belt around the drive roller and the supply hub.

Put the takeup hub on its pin.

Put the empty tape hub on its pin.

Using the top to hold the floating roller, belt and supply hub down, use a straightened paper
clip or pencil to guide the elastomer belt around the hub. The hub should seat against the
base with the belt around it.

D.3.2 Threading the Cartridge

Pull several centimeters (a few inches) of tape off the supply hub and through the tape guides
(Figure D-5).
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 D.3.•.

TAKE

SUPPLY

HUB

Figure D-5

HUB

Threading the Plastic-Base Cartridge

Moisten the end of the tape with water to get it to stick to the hub.

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.

As soon as the tape is grabbed, keep some back tension on the tape. This keeps the tape
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 paper clip. (Back up if the end is too long.)

Continue to wind a few more turns with the floating roller while applying tension to the tape.

Now hold the take up hub, drive roller, and floating rollers fixed and rotate the supply hub to
take up the slack.
]),4

D.3.3 Closing the Cartridge
Place the top back on the cartridge. Do not reinstall the head gate. The mirror window may need to be
pressed in slightly to clear the bottom. Reinstall the four baseplate screws.
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 possible. Discard the cartridge after copying.

0-5

APPENDIXE
FIELD REPLACEABLE UNIT SPARES LIST

Module
Serial Controller Board
Regulator Module
Drive
Tachometer Encoder Wheel
Tape Cartridge

DIGITALP/N
54-13489
54-13609
70-15510
74-20649
36-15809

B-1

Option Name
TU58-XB
TU58-XA
TU58-K

Digital Equipment Corporation. Maynard, MA 01754