Olivetti DE 520 Series User manual

DE 520 SYSTEM
and Magnetic Tapes
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THE DE 520 SYSTEM
AND MAGNETIC TAPES
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Produced by
I DP Software
British Olivetti Limited
30 Berkeley Square
London
W1X 6AH

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PREFACE
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This manual explains the functions of the two magnetic tape options on the DE 520
System:
1Magnetic Tape Cassette Option
2 Computer Compatible Tape Option
The manual is split into two sections. The first section, Cassettes System, details the
operations that can apply to both cassette and computer tape options. The second
section, Computer Magnetic Tape, details the differences in operation for computer
compatible tape applications.

CONTENTS Page
Preface '
Contents 1
Introduction 2
THE DE 523 AND CASSETTES SYSTEM 4
Cassette Handling 4
Size of Cassette Tape 4
Record Handling Techniques 4
Read 4
Read Errors (Parity) 5
F?ead Errors (Overflow) 5
Equipment Errors 5
Backspace 5
Write 5
Write Errors (Parity) 5
Write Errors (Equipment) 5
Write File 6
Rewind 6
TERMINAL OPERATION 7
Selecting and Processing 7
Manual Control 7
OPERATIONAL MODES USING CASSETTES 8
Free-Form Mode 8
Enter Mode 9
Verify Mode 9
Search Under Batch Mode "JO
Error Messages
THE DE 523 AND COMPUTER MAGNETIC TAPE 14
Introduction "'4
TAPE OPERATIONS 15
Read "IS
Backspace 15
Write "'S
Write File 15
Rewind 15
Insert 15
TERMINAL OPERATION 16
Selection and Processing 16
Operational Modes using the Computer Tape 16
Free-Form Mode 16
Enter Mode 16
Verify Mode 17
Batch Mode ''7
Tape Errors 17
Appendix A Tape Error Messages
B International: ASCII-BCD Conversion Table
C International: ASCII-EBCDIC Conversion Table
DTypical Computer Tape Format on the DE 520 System
Figures 1 Beginning-of-Tape & End-of-Tape Areas 12
2 Nominal Record (Cassettes) 12
3 Recording Bit Pattern 13
1.

INTRODUCTION
The central unit of the Olivetti DE 520 System is equipped with cassette recorders. The
standard DE 521 has one cassette recorder, the DE 523 has two. The DE 521 has the
option of a second cassette. Cassette recorders can be assigned for either Input or
Output operations.
There are two recording tracks on the cassette magnetic tape, one track for data and the
other for a bit parity check. Two possible inter-record gap sizes are available: 0.75 inch
and 1.5 inch (CRR-IB compatible). The 0.75 inch ihter-record gap is standard on the DE
520 System, the 1.5 inch inter-record gap is optional.
Data is recorded using the extended ISO/USASCII Code (7+ 1+ 1 bits).
The recording density is 800 bpi (80 characters). Read/Write speed is 12.5'ips, with a
rewind speed of 120 ips.
Each cassette tape is 280 feet (90 metres) in length; the effective capacity being 1,000-
2,000 records depending on record size, 216-80 characters respectively and the size of
inter-record gaps.

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THE DE 523 AND CASSETTES SYSTEM
CASSETTE HANDLING
It should be noted that the correct handling of cassettes is of prime importance.
To insert the cassette into its compartment:
1. Open the compartment door by pressing the catch downwards.
2. Insert the cassette into the compartment by holding the top and bottom of the
»cassette between the index finger and thumb (see photograph opposite). Special
care should be taken not to handle the exposed part of the magnetic tape.
3. Slot the cassette into the compartment by inserting the right edge slightly ahead
of the left edge (see photograph opposite).
4. Close the compartment door.
To remove the cassette from its compartment:
1. Open the compartment door by pressing the catch downwards.
2. Hold the top and bottom of the cassette and move it slightly to the right before
removal. The left edge of the cassette should be withdrawn first.
NOTE: AT ALL TIMES THE CASSETTES MUST BE REWOUND PRIOR TO THEIR
REMOVAL.
SIZE OF CASSETTE TAPE
The cassette tape is 280 feet (90 metres) long with the effective capacity of each
cassette consisting of 1.000-2.000 records depending on record size, 216-80 characters
respectively, and the size of inter-record gaps.
RECORD HANDLING TECHNIQUES
I The cassette recorder feature provides the terminal with the ability to read, write,
I ^ backspace, insert, write file marks, and rewind cassette tapes. The operations,
I 'W themselves, can be performed under the control of format programs provided with the
I cassette system. Sincc the recorders share the same interface, it is not possible to
I overlap operations on the first recorder with those of the second recorder. It is, however,
I possible to overlap cassette input/output operations with other peripheral operations,
i providing the terminal's overlap rules are satisfied (see DE 520 General Manual,
V pSiQQ 14).
I
4
5
^ READ
The Read operation reads the next available record from the selected cassette into the
buffer specified by the terminal control. If the "Clear Leader" is detected prior to the
initiationof the read operation the cassette recorder assumes that it is at the beginning-
of-tape (BOT), and advances the tape beyond the Clear Leader. If Clear Leader is
detected during a read operation the cassette recorder assumes it is at the end-of-tape
(EOT), the tape is retarded 0.25 inches from the Clear Leader and the read operation
terrninales with the message EOT displayed on the screen.

READ ERRORS (PARITY)
When a parity error has occurred there are three further attempts to read the record from
the cassette, this is achieved by backspacing over the error record and re-reading it. If
the fourth attempt to read the record is unsuccessful the first character in the record is
replaced by the @ character and the read error message RD appears on the screen.
IT SHOULD BE NOTED THAT THE DATA FROM THE ERROR RECORD IS STORED IN
THE SPECIFIED INPUT BUFFER.
READ ERRORS (OVERFLOW)
When a record containing more than 216 characters is read, all the data after the 216th
character is "lost". Parity is checked on the entire record and there is no screen
message for overflow conditions.
EQUIPMENT ERRORS
If at any time during aread operation the cassette recorder is found to be non-
operational,
the operation is terminated and an error message displayed on the screen.
(See Cassette Recorder Messages, page 11, for appropriate action).
BACKSPACE
The backspace operation moves the selected cassette tape back one record. Ifthe Clear
Leader is detected the operation is terminated without an error indication. If the cassette
recorder is non-operational the operation is terminated without an error indication.
WRITE
The Write operation transfers the data in the specified buffe* onto the selected cassette
tape. The DE backspaces the record, and reads it at reduced sensitivity to check the
parity of the record. Ifthe Clear Leader is detected prior to the Write operation the DE
assumes that it is at the beginning-of-tape (BOT) and the tape is erased until it is 3.5
inches beyond the Clear Leader. When the Clear Leader is detected during a Write
operation the DEassumes that it is at the end-of-tape (EOT); the cassette is backspaced
0.25 inch from the Clear Leader and the operation is terminated with the EOT message
displayed on the screesi.
WRITE ERRORS (PARITY)
When a parity error is detected the record is backspaced and 3.5 inches of tape erased,
the DE then performs the Write operation. This process is repeated until the Write
operation is completed successfully.
WRITE ERRORS (EQUIPMENT)
If the cassette is pi'otected from Write operations, by the physical removal of the plastic
insert at the edge of a cassette, the Write cporatior. is not performed and an error
message displayed on the screen. (See Cassette Recorder Messages, page 11, for
appropriate action).

WRITE FILE
The Write File operation writes an end-of-file mark consisting of 3.5 inches of tape
erased
followed by a singlecharacter record containing the FS character.The record is
written without an LRC. The rules governing Clear Leader, protected cassettes, non-
operational recorders and parity error are identical to the Read operation.
REWIND
The Rewind operation rewinds the selected cassette tape until the beginning-of-tape
(BOT) Clear Leader is sensed. If thetape is positioned on a Clear Leader at the time the
operation is initiated the Rewind function is not performed. It is not possible to rewind a
cassette positioned at EOT and on the Clear Leader. This operation is similar to the
Read and Write operations in that it follows the convention of backspacing away from
EOT thus making the rewind operation possible.

TERMINAL OPERATION
SELECTING AND PROCESSING
When the terminal is provided with the Cassette Recorder feature the cassette recorders
may be selected as normal terminal inputs and outputs during I/O assignment. The
following device identification codes are reserved to identify the cassette recorder
compartment positions.
device code
1
2
function
Select left-hand cassette recorder
Select right-hand cassette recorder
Entering these identification codes on the status line results in the specified cassette
recorder being selected as a source of, or destination for, data during the terminal's
normal course of operation. If the terminal has not been provided with a second cassette
recorder compartment (standard DE 521), and it is selected, then the operation results in
an EQP error being displayed on the screen. The direction of data transfer is determined
by whether the specified recorder has been assigned as an input or an output device. It
should be noted that format programs, if used, are usually stored on one of the two
cassettes. This cassette is therefore encoded as the format device in the assignment
code.
MANUAL CONTROL
Manual control of cassette recorder operations is possible through the use of the Device
Operation keys. The functions of these keys are as follows:
key function
Adv Red Loads the input buffer into the output buffer, clears the input buffer and
reads the next record from the selected cassette into the input buffer.
Back Red Backspaces the selected cassette tape one record.
Write Loads the input buffer into the output buffer, clears the input buffer and
write the contents of the output buffer onto the selected cassette tape.
Insert Loads the input buffer into the output buffer, clears the input buffer and
inserts the contents of the output buffer onto the selected cassette tape.
The insert operation is performed by backspacing the selected cassette
• and writing the output buffer onto it. CARE MUST BE TAKEN TO
ENSURE THAT THE LENGTH OF INSERTED RECORD DOES NOT
DIFFER FROM THAT OF THE ORIGINAL RECORD.
Write File Writes FS onto the selected casseite tape.
Rew Rewinds the selected cassette tape.

message
RD
EOF
EOT
EOT
EQP
EQP
EQP
APPENDIX A
TAPE ERROR MESSAGES
meaning
A read error has been en
countered in the process of in
putting data from the computer
tape.
An end-of-file mark has been
read on the computer tape.
The end-of-tape mark has been
read while inputting from the
computer tape.
The end-of-tape mark has been
read while outputting to the com
puter tape.
An attempt to perform a tape
operation has been made and the
transport is non-operational.
An attempt to insert onto the
computer tape has been made.
An attempt has been made to
perform an output operation to a
protected tape.
corrective action
(1) To accept record-depress
the Error Reset key.
(2) To re-read record - depress
Back Red, Adv Red and Error
Reset keys.
(3) To skip record - depress Adv
Red key.
(1) To process EOF mark to out
puts-depress the Error
Reset key.
(2) To skip into the next
file-depress the Adv Red
and Error Reset keys.
Depress the Rew key, load a new
tape, depress Adv Red and Error
Reset keys to continue.
Depress the Rew key, load a new
tape, depress Write and Error
Reset keys to continue.
Make the transport ready,
depress the appropriate Device
Operation key and the Error
Reset key to repeat the tape
operation.
No corrective action possible.
Remove the tape, provide the
ring (removed to effect protec
tion) and restart operation from
the beginning.

z
» Data
Record
Four
Character
Spaces
Cyclic
Redundancy
Check (CRC)
Character
APPENDIX D
TYPICAL COMPUTER TAPE FORMAT ON THE
DE 523 SYSTEM
Forward tape motion
N.B. (i) For an End-of-Tape Record, no CRC
is present.
(ii) With a 7-track tape, no CRC is present.
z
, Inter
Record
Gap .
.Longitudinal
Redundancy
Check (LRC)
Character
.Four
Character
Spaces

OPERATIONAL MODES USING CASSETTES
FREE-FORM MODE
Jhis is the mode in which assignment codes are set-up via the keyboard. If set-up as
follows:
* 1 _ _ _ * (each _ indicating a space)
the cassette recorder in position 1 is assigned as a FMAT device, and format programs
and descriptions can be written onto the cassette via the keyboard and the device
oiDeration keys; these keys also allow the retrieval of formats or descriptions from the
cassette into the buffer where any necessary corrections can be made. The formats or
descriptions can then be written back into their relevant record positions on the cassette
medium.
For example, to set-up records which have the details:
Date
Name
Address
Invoice No.
Amount
1. Key in the format program (see DE 520 General Manual pages 16 & 19)
F (,
DP y D
' ♦ • • • ^ •"
2. Depress Fmat (Device Control) key
3. Depress Write key
4. Depress Back Red key
5. Depress Adv Red key
The format program should be displayed on the screen.
6. Depress Free-Form key
It should be possible to key-in a description for each of the fields within the format
program v^ritten on the cassette and displayed on the screen. Using the cursor as a
guide, the following data can be entered, via the keyboard, above the relevant fields
displayed:
DATE NAME ADDR
ESS INV. NO. AMOUNT
7. Depress Fmat key
8. Depress Write key
9. Depress Rew key
The field control characters used in the format program are explained in the DE 520
General ivianuai. Eacii coiiirol characler represents one character position of its defined
field. The.control characier plus the number of full stops (.) or commas (,) determines the
capacity of each field.

Full stops and commas can be encoded within the same alphanumeric field if such a
control is desirable. For example, to record an alphanumeric field whilst specifying the
exact location of numeric characters would be obtained in a similar format to the
following:
(i t 1 I t • • • « » »
ENTER MODE
This is a mode in which operator entry is controlled by a format program in either of the
two program buffers. For example, to set up records using the format program that had
just been written:
1. Insert the second cassette (without altering the position of the first cassette) into
the second cassette compartment.
2. Depress the Free-Form key.
3. Depress the I/O SIct key.
4. Key in the assignment code:
* 1 _ 2 *
Format Cassette-I
Output Cassette
5. Depress the Enter key
6. Depress the Next Fmat key.
This loads the program buffers with the format program and the description from
cassette 1.
7. Depress Prog. 1 key.
This indicates that the control of entry should be by the format program in program 1
buffer and not by the description in program 2buffer.
Note: The first line of the format program and the first line of the description are
displayed. The current data line determines which format and description lines are
displayed.
8. Depress the Skip Bar to advance from one field to another.
At the end of each record the data is automatically written onto the second cassette.
VERIFY IVIODE
In this mode, using the same example as in the Enter Mode description, the output
device assignment code is set-up as:
* 1 2 *
Format Cassette^
Input Cassette
The second cassette becomes the input device (in the Enter mode example it was
assigned as an output device). Records that had been set-up in the Enter mode can be
keyed in again, and this mode ensures aGcquentia! character-by-character chock
according to the format program. The controlling format program might be the same as
that used tc set up the records or might be a different one which checks only specified
fields within the rccords.
Any corrected records are automatically inserted onto the input device.

SEARCH UNDER BATCH MODE
Before operating in this mode a search format has to be loaded into program 1 buffer. As
far as the assignment code is concerned, an input device must be assigned. Depending
upon the processing to be carried out, it may be necessary to assign a format device
and/or output devices. For example, if the operation is simply to write the records from
the second Cassette Recorder onto the first Cassette Recorder the assignment codes
should be:
* - 2 1 _ *
1. Depress the Comp key
2. Depress the Load key
» 3. Depress the 1 key
This loads the complete character, which acts as a search format, into the program 1
buffer.
. 4. Depress the Batch key to start the processing.
In Batch mode, it is possible to search for any particular record held on the input device.
Upon completion of the search the record can either be held and displayed or written out
to an assigned output device. With this type of processing the following points should be
noted.
a. A search format should be loaded into program 1 buffer.
b. The search parameter characters, alpha or numeric, must be placed in the
same position as they would appear in the required record.
c. Character positions not to be compared are filled with 'SKIP' characters when
keying the search format.
d. If searching for a record to be held and displayed, the AUTO REL switch should
be OFF.
e. If searching and pooling records onto an output device, the AUTO REL switch
should be ON.
Examples of possible search formats are detailed below. Each record on the input device
might have the following fields:
Counter field ( 5 characters)
Name (10 characters)
Address (12 characters)
Date ( 6 characters)
Invoice No. (4 characters)
Example of a typical record:
00006JOE BL0GGS14 High St. 1706721403
A search format - 6B would find records which have counter fields ending in a
six i.e. 6, 16, 26, 36 etc. A search format JOE BLOGGSO would find records
(or record) with the name Joe Bloggs on them.
The search format 8J0E BLOGGS 17S
would find a record (or the records) with a six as the last digit of the counter field
and The name JOE BLOGGS as well as the first two digits of the date field (being 17) i.e.
three conditions to be satisfied by the record (or records).
THE SEARCH FORMAT • ALLOWS EVERY RECORD ON THE INPUT CASSETTE TO BE
"FOUND"
See above-Search Under Batch mode, for description of how to write this format.
10

ERROR MESSAGES
Error messages, their meanings, and possible corrective actions, using cassettes, are
listed below:
message
RD
WR
EOT
EQP
EQP
EQP
CASSETTE RECORDER MESSAGES
meaning
A read error has been en
countered in the process of
reading the selected cassette.
A write error has been en
countered in the process of in
serting on the selected recorder.
Clear Leader has been sensed in
the process of inputting data
from the selected cassette
An attempt to input or output has
been made and the selected
cassette is non-operational.
An attempt has been made to
output to a protected cassette.
An attempt has been made to in
put or output to the second
cassette recorder which is not
provided on the terminal, e.g. en
coding a 2 as an input or output
device on the DE 521.
11
corrective action
(1) To accept record depress
Error Reset key.
(2) To re-read record depress
Back Red, Adv Red, and
Error Reset keys.
(3) To skip record depress Adv
Red and Error Reset keys.
ATTEMPT UNDER F-FORM
MODE CONTROL. If the error
persists create new cassette.
Depress Rew key, load a new
cassette and depress Adv Red
and Error Reset keys to continue.
Make the recorder ready, repeat
the operation resulting in the
error using the Device Operation
keys and depress the Error Reset
key.
If an insert is desired depress the
recorder protection override
button and then depress Insert
and Error Reset keys.
Depress Free-Form and correct
I/O assignment codes.

CASSETTE TAPE FORMAT
Initial Gap 3.5"
/
1
Clear Read/Write
Leader head
Sensor
FIG. 1 BEGINNING-OF-TAPE & END-OF-TAPE AREAS
Read or Write head with tape stationary
Q
Short Distance
Start Delay
Start-of-Record _
Mark (Transition
Four Character.
Spaces
Bit)
Data Record
"vx
Tape Record
/
FIG. 2 NOMINAL RECORD
12
Stop Distance
Stop Delay
Logical
Redundancy
Bit (LRB)
LRB= 0 if odd
number of
characters
in record
LRB= 1 if even
number of
characters
in record

RECORDING ON DE 520 SYSTEM CASSETTE MEDIUM (NRZI 800 bpi)
8 bits of data
8 bits of data ^L-»|
101100101 1 10101010A
01001 1 0 1 0 0 0 1010101B
%
{( Tape data byte
C
D
A. Data Track
B. Parallel Parity Track
C. Data Track Flux
D. Parallel Parity Track Flux
LLogical Redundancy Bit
FIG. 3 RECORDING BIT PATTERN
13

THE DE 523 AND COMPUTER
MAGNETIC TAPE SYSTEM
INTRODUCTION
The DE 523 Computer Magnetic Tape Option provides the terminal with the ability to
read, write, backspace, write file marks and rewind computer tape. The operations are
performed under the control of the programs provided with the tape option package and
are not overlapped with the terminal's other operations because of the tape transport's
high data transfer rate i.e. the terminal is Mocked out' while these operations are being
performed.
The tape option interfaces the terminal with a 12.5 ips 0.5 inch computer tape transport
for recording and reading nine-track data at 800 bpi or 1600 bpi (EBCDIC) or seven-track
BCD data at 556 bpi or 800 bpi. When interfaced to the terminal, via an appropriate
interface unit, the computer tape becomes a normally selectable Input/Output device for
terminal I/O operations. Provisions are made in the terminal to allow for the installation
of this option at field level.
The magnetic tape option consists of a set of programs for controlling the option, a tape
interface, a connecting cable and tape transport. The programs for controlling the option
and the ASCII/BCD or ASCII/EBCDIC conversion tables are supplied in two MOS, Read-
Only-Memory, IC chips. Sockets are reserved on the terminal's memory board to
accommodate these chips, plugging in the chips enables the programs. The computer
tape transport is controlled from the terminal via a two-card interface. The terminal card
file is wired at the time of manufacture to accommodate these cards.
The 'Jumpable' options exist on the interface. On the seven-track unit the first of these
options allows the selection of either 800 bpi or 556 bpi recording, and the second allows
the selection of odd or even parity.
The same interface is employed for both the seven and nine-track options, when using,
the nine-track option the jumps select 800 bpi odd parity recording.
7 track tape is written in BCD at 556 bpi or 800 bpi.
9 track tape is written in EBCDIC at 800 bpi or 1600 bpi.
N..B. Particular attention should be paid to the tape loading instructions supplied with
the magnetic tape unit.
14