Information technology — 3,81 mm wide magnetic tape cartridge for information interchange — Helical scan recording — DDS-2 format using 120 m length tape

Specifies the physical and magnetic characteristics of a 3,81 mm wide magnetic tape cartridge to enable physical interchangeability of such cartridges between drives and specifies the quality of the recorded signals, the recording method and the recorded format.

Technologies de l'information — Cartouche de bande magnétique de 3,81 mm de large pour l'échange d'information — Enregistrement par balayage en spirale — Format DDS-2 utilisant une bande de 120 m de long

General Information

Status
Published
Publication Date
25-Dec-1996
Current Stage
9093 - International Standard confirmed
Start Date
22-Mar-2006
Completion Date
21-Aug-2020
Ref Project

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ISO/IEC 13923:1996 - Information technology -- 3,81 mm wide magnetic tape cartridge for information interchange -- Helical scan recording -- DDS-2 format using 120 m length tape
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ISO/IEC
INTERNATIONAL
13923
STANDARD
First edition
1996-l 2-15
Information technology - 3,81 mm wide
magnetic tape cartridge for information
Helical scan recording -
interchange -
DDS-2 format using 120 m length tape
Cartouche de bande magn&lque de
Technologies de /‘information -
3,81 mm de large pour I’khange d’information - Enregistrement par
balayage en spirale - Format DDS-2 utilkant une bande de 120 m de long
Reference number
GO/I EC 13923: 1996(E)
---------------------- Page: 1 ----------------------
ISO/IEC 13923:1996(E)
Contents
Page
Section 1 - General
1 Scope
Conformance
Magnetic tape cartridge
2.1
2.2 Generating system
2.3 Receiving system
3 Normative References
4 Definitions
4.1 Absolute Frame Number (AFN)
4.2 a.c. erase
Access Point
4.3
4.4 Algorithm
4.5 Area ID
Automatic Track Finding (ATF)
4.6
4.7 Average Signal Amplitude
4.8 azimuth
back surface
4.9
4.10 byte
4.11 cartridge
Channel Bit
4.12
4.13 Codeword
4.14 Data Format ID
Early Warning Point (EWP)
4.15
4.16 End of Data (EOD)
Entity
4.17
4.18 Error Correcting Code (ECC)
4.19 flux transition position
flux transition spacing
4.20
4.21 Frame
4.22 Housekeeping Frame
4.23 Logical Beginning of Tape (LBOT)
4.24 magnetic tape
0 ISODEC 1996

All tights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in

any form or by any means, electronic or mechanical, including photocopying and microfilm, without

permission in writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CH- P 2 11 @en&e 20 l Switzerland
Printed in Switzerland
---------------------- Page: 2 ----------------------
ISOAEC 13923:1996(E)
0 ISO/IEC
4.25 Master Standard Amplitude Calibration Tape
Master Standard Reference Tape
4.26
4.27 Optimum Recording Field
4.28 Partition Boundary
4.29 Physical Beginning of Tape (PBOT)
4.30 Physical End of Tape (PEOT)
physical recording density
4.31
4.32 pre-recording condition
4.33 processing
4.34 processed data
4.35 Processed Record
4.36 Processed Record Sequence
4.37 record
Reference Recording Field
4.38
4.39 reprocessing
4.40 Secondary Standard Amplitude Calibration Tape
4.41 Secondary Standard Reference Tape
Separator Mark
4.42
4.43 Standard Reference Amplitude
4.44 Tape Reference Edge
Test Recording Current
4.45
4.46 track
4.47 unprocessed data
4.48 Unprocessed Record
Virtual End of Tape (VEOT)
4.49
5 Environment and safe ty
5.1 Testing environment
5.2 Operati ng en vironment
Storage environment
5.3
Transportation
5.4
5.5 Safety
5.6 Flammability
Section 2 - Requirements for the case
Dimensional and mechanical characteristics of the case
General
6:2 Overall dimensions
6.3 Loading grip
6.4 Holding areas
Notches of the lid
6.5
6.6 Lid dimensions
6.7 Optical detection of the beginning and end of tape
Bottom side
68 .
6.8.1 Locking mechanism of the slider
6.8.2 Access holes
6.8.3 Recognition, write-inhibit and sub-datums holes
6.8.4 Datum holes
6.8.5 Access room for tape guides
6.8.6 Holes for accessing the hubs
6.8.7 Internal structure of the lower half
6.8.8 Light path
6.8.9 Support Areas
6.8.10 Datum Areas
6.8.11 Relationship between Support and Datum Areas and Reference Plane 2
..O
111
---------------------- Page: 3 ----------------------
0 ISO/IEC
ISO/IEC 13923:1996(E)
6.9
Hubs
6.10 Attachment of leader and trailer tapes
6.11 Interface between the hubs and the drive spindles
6.12 Opening of the lid
6.13 Release of the hub locking mechanism
Label areas
6.14
6.15 Requirement for autoloaders
Section 3 - Requirements for the unrecorded tape
7 Mechanical, physical and dimensional characteristics of the tape
7.1 Materials
7.2 Tape length
7.2.1 Length of magnetic tape
7.2.2 Length of leader and trailer tapes
Length of splicing tapes
7.2.3
Tape width
7.3
7.3.1 Width of magnetic, leader and trailer tapes
Width and position of splicing tape
7.3.2
7.4 Discontinuities
Tape thickness
7.5
7.5.1 Thickness of magnetic tape
7.5.2 Thickness of leader and trailer tapes
7.5.3 Thickness of splicing tape
7.6 Longitudinal curvature
7.7 Cupping
Coating adhesion
7.8
7.9 Layer-to-layer adhesion
7.10 Tensile strength
7.10.1 Breaking strength
7.10.2 Yield strength
7.11 Residual elongation
7.12 Flexural rigidity
Electrical resistance of coated surfaces
7.13
Light transmittance of the tape
7.14
7.15 Media Recognition System (MRS)
8 Magnetic recording characteristics
81 . Optimum Recording Field
82 Signal Amplitude
Resolution
8:3
Overwrite
84 .
750,O ftpmm and 2 999,9 ftpmm
8.4.1 Physical recording densities
000,O ftpmm
of 83,3 ftpmm and 1
8.4.2 Physical recording densities
85 Ease of erasure
8:6 Tape quality
8.6.1 Missing pulses
Missing pulse zone
8.6.2
Signal-to-Noise Ratio (S/N) characteristic
8.7
---------------------- Page: 4 ----------------------
ISO/IEC 13923:1996(E)
0 ISO/IEC
Section 4 - Requirements for an interchanged tape
9 Format
91 . General
Basic Groups
92 .
Entity
9.2.1
Group Information Table
9.2.2
9.2.3 Block Access Table (BAT)
93 . Sub-Groups
9.3.1 G 1 Sub-Group
9.3.2 G2 Sub-Group (randomizing)
G3 Sub-Group
9.3.3
9.3.4 G4 Sub-Group
9.3.5 Main Data Block
9.4 Sub-Data Area
9.4.1 Pack Item Number 1
9.4.2 Pack Item Number 2
Pack Item Number 3
9.4.3
9.4.4 Pack Item Number 4
9.4.5 Pack Item Number 5
Pack Item Number 6
9.4.6
9.4.7 Pack Item Number 7
9.4.8 Pack Item Number 8
9.4.9 Sub Data Block
10 Method of recording
10.1 Physical recording density
10.2 Long-term average bit cell length
Short-term average bit cell length
10.3
10.4 Rate of change
10.5 Bit shift
10.6 Read signal amplitude
10.7 Maximum recorded levels
11 Track geometry
11.1 Track configuration
Average track pitch
11.2
11.3 Variations of the track pitch
11.4 Track width
Track angle
11.5
11.6 Track edge linearity
11.7 Track length
Ideal tape centreline
11.8
11.9 Azimuth angles
Recording of blocks on the tape
12.1 Recorded Main Data Block
Recorded Sub Data Block
12.2
12.3 Margin Blocks, Preamble Blocks and Postamble Blocks
12.4 Spacer Blocks
---------------------- Page: 5 ----------------------
0 ISO/IEC
HSOIIEC 13923:1996(E)
Format of a track
13.1 Track capacity
13.2 Positioning accuracy
13.3 Tracking scheme
14 Layout of a Single Data Space tape
14.1 Device Area
14.2 Reference Area
14.3 Position Tolerance Band No. 1
System Area
14.4
14.4.1 System Preamble
System Log
14.4.2
14.4.3 System Postamble
14.4.4 Position Tolerance Band No. 2
14.4.5 Vendor Group Preamble
14.5 Data Area
Vendor Group
14.5.1
14.5.2 Recorded Data Group
14.5.3 ECC3
14.5.4 Multiple recorded instances
Repeated Frames
14.5.5
Appending and overwriting
14.5.6
EOD Area
14.6
Post-EOD Area
14.7
14.8 Early Warning Point - EWP
14.9 Initialization
15 Layout of partitioned tape
Overall magnetic tape layout
15.1
15.1.1 Device Area
Partition 1
15.1.2
Partition 0
15.1.3
15.2 Area ID
15.3 System Area Pack Items No. 3 and No. 4
15.4 Empty partitions
15.4.1 partition 1
Empty
partition 0
15.4.2
Empty
Initialization of partitioned tapes
15.5
16 Housekeeping Frames
16.1 Amble Frames
System Log Frames
16.2
Tape Management Frames
16.3
---------------------- Page: 6 ----------------------
0 ISO/IEC ISO/IEC 13923:1996(E)
Annexes
A - Measurement of the light transmittance of the prisms
B - Recognition Holes 81
C - Means to open the lid 82
D - Measurement of light transmittance of tape and leaders
E - Measurement of Signal to Noise Ratio

F - Method for determinating the nominal and the maximum allowable recorded levels 87

G - Representation of g-bit bytes by lo-bit patterns 88
H - Measurement of bit shift 94
J - Recommendations for transportation
K - Method of measuring track edge linearity
L - Read-After-Write 98
M - Example of the content of a Basic Group No. 0 99
---------------------- Page: 7 ----------------------
ISOJIEC 13923:1996(E) 0 ISO/IEC
Foreword

IS0 (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the

specialized system for worldwide standardization. National Bodies that are members of IS0 or IEC participate in the

development of International Standards through technical committees established by the respective organization to deal with

particular fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with IS0

and IEC, also take part in the work.

In the field of information technology, IS0 and IEC have established a joint technical committee ISO/IEC JTC 1. Draft

International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an

International Standard requires approval by at least 75% of the national bodies casting a vote.

This International Standard was prepared by JISC (as Standard JIS X.6129-1993) with document support and contribution

from ECMA and was adopted, under a special “fast-track procedure”, by Joint Technical Committee ISO/IEC JTC 1,

Information technology, in parallel with its approval by national bodies of IS0 and IEC.

Annexes A, D, E, F, G, H and K form an integral part of this International Standard. Annexes B, C, J, L and M are for

information only.
. . .
Vlll
---------------------- Page: 8 ----------------------
ISO/IEC 13923:1996(E)
0 ISO/IEC
Introduction

for cassettes and c -artridges containing magnetic tapes of different width and characteristics

Numerous International Standards
following rel ate to helical scan recording.
have been published. Of these, the
3,6I mm wide magnetic tape cartridge for information interchange -
ISO/IEC 10777: 1991 Information technology -
Helical Scan Recording - DDS format

ISO/IEC 11319:1993 Information technology - 8 mm wide magnetic tape cartridge for information interchange - Helical

scan recording

ISO/IEC 11321:1992 Information technology - 3,81 mm wide magnetic tape cartridge for information interchange -

Helical scan recording - DATMDAT format

ISO/IEC 11557: 1992 Information technology - 3,81 mm wide magnetic tape cartridge for information interchange -

Helical scan recording - DDS-DC format using 60 m and 90 m length tapes

ISO/IEC 12246: 1993 Information technology - 8 mm wide magnetic tape cartridge dual azimuth format for information

interchange- Helical scan recording

ISO/IEC 12247: 1993 Information technology - 3,8I mm wide magnetic tape cartridge for information interchange -

Helical scan recording - DDS format using 60 m and 90 m length tapes

ISO/IEC 12248: 1993 Information technology - 3,81 mm wide magnetic tape cartridge for information interchange -

Helical scan recording - DATMDAT-DC format using 60 m and 90 m length tapes

ISOLIEC 10777 defines a specification for data interchange using 3,81 mm wide magnetic tape cartridges, with the DDS

format.

A derivative International Standard ISO/IEC 11557 defines another data interchange specification for the same cartridges, but

with a recorded format, namely DDS-DC, which enables data to be compressed by the drive before being recorded.

This International Standard defines a specification, based on the features of both of these, which offers a further increase in

data capacity. The primary change to the recorded format is an increase in the track density by a factor of 1,5. This produces a

corresponding increase in data capacity for a cartridge of a given tape length. Such a track density, when recorded on a

cartridge tape whose tape length is 125 metres, will provide a storage capacity of 4 Gigabytes of uncompressed user data and

typically 8 to 16 Gigabytes of compressed user data.

The design philosophy is one of minimum change to the track format which is common to DDS and DDS-DC. This will aid

the development of drives that support this DDS-2 format by derivation from existing products. It will also ease the

development of drives that are able to support both previous formats as well as this format, thus providing the backwards

compatibility which the market demands. However, it is not a requirement for compliance to this International Standard that a

drive also reads and writes either the DDS format or the DDS-DC format. Nor is it a requirement for compliance to this

International Standard that a drive compresses data and writes it in entities on the tape, or that a drive decompresses data

contained within entities on the tape. All the recording on one cartridge will be at the same track density, either that of DDS

and DDS-DC, or that of DDS-2. The media coating and the track density are indicated by the combination of the states of the

Recognition Holes on the cartridge case.

This International Standard also includes the specifications of the Media Recognition System, namely a striped splicing tape.

---------------------- Page: 9 ----------------------
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---------------------- Page: 10 ----------------------
INTERNATIONAL STANDARD 0 ISO/IEC ISO/IEC 13923: 1996(E)
Information technology - 341 mm wide magnetic tape cartridge for information
interchange - Helical scan recording - DDS-2 format using 120 m length tape
Section 1 - General
1 Scope

This International Standard specifies the physical and magnetic characteristics of a 3,81 mm wide magnetic tape cartridge to

enable physical interchangeability of such cartridges between drives. It also specifies the quality of the recorded signals, the

recording method and the recorded format, thereby allowing data interchange between drives by means of such magnetic tape

cartridges.

The recorded format, known as DDS-2, includes all the features of the DDS recorded format specified in ISO/IEC 12247 and

of the DDS-DC recorded format specified in ISO/IEC 11557. The principal difference between this recorded format and those

recorded formats is the use of a greater track density by this format.

Information interchange between systems utilising this International Standard also requires the use, as a minimum, of a

labelling specification, e.g. IS0 1001: 1986, Information processing - File structure and labelling of magnetic tapes for

information interchange, and an interchange code which shall be agreed upon by the interchange parties.

Under information interchange circumstances in which a processing algorithm is applied to the host data prior to recording on

the tape and a complementary reprocessing algorithm is applied after the data is read from the tape, agreement upon the

algorithms employed by the interchange parties is also required. It is outside the scope of this International Standard to specify

any of these.
Conformance
Magnetic tape cartridge
2.1

A tape cartridge shall be in conformance with this International Standard if it meets all the mandatory requirements specified

herein. The tape requirements shall be satisfied throughout the extent of the tape.

For each recorded Entity any algorithm used for Processing the data therein shall have been registered, and the registration

identification shall be included, when appropriate, in Byte No. 3 of the Entity Header.

A recorded tape shall be either a Single Data Space Tape or a Partitioned Tape.
2.2 Generating system

A system generating a magnetic tape cartridge for interchange shall be entitled to claim conformance with this International

Standard if all recordings on the tape meet the mandatory requirements of this International Standard, and if either or both

methods of appending and overwriting are implemented.

A claim of conformance shall state which of the following optional features are implemented and which are not

the performing of a Read-After-Write check and the recording of any necessary repeated frames;

the recording of multiple representations of the same Basic Group;
the generation of ECC3 Frames.
In addition a claim of conformance shall state

whether or not one, or more, registered algorithm(s) are implemented within the system and are able to process data

received from the host prior to collecting the data into Basic Groups, and

- the algorithm registration identification number(s) of the implemented algorithm(s).

---------------------- Page: 11 ----------------------
ISO/IEC 13923:1996(E) 0 ISO/IEC
2.3 Receiving system

A system receiving a magnetic tape cartridge for interchange shall be entitled to claim full conformance with this International

Standard if it is able to handle any recording made on the tape according to this International Standard. In particular it shall

Separator Marks from only one of these
be able to recognize repeated Frames and to available to the host, data and
Frames;

- be able to recognize multiple representations of the same Basic Group, and to make available to the host, data and

Separator Marks from only one of these representations;

- be able to recognize an ECC3 Frame, and ignore it if the system is not capable of using ECC3 check bytes in a process of

error correction;
be able to update the System Log(s) if the Write-inhibit Hole state so permits;
the algorithm registration

be able to recognize processed data within an Entity, identify the algorithm used, and make

number available to the host;
- be able to make processed data available to the host.
In addition a claim of conformance shall state

whether or not the system is capable of using ECC3 check bytes in a process of error correction;

whether or not one or more Reprocessing algorithm(s) are implemented within the system, and are able to be applied to

Processed Data prior to making such data available to the host;
algorithm is

the algorithm registration number(s) of the processing algorithm(s) for which a complementary Reprocessing

implemented.
3 Normative References

The following standards contain provisions which, through reference in this text, constitute provisions of this International

Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to

agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent

editions of the standards indicated below. Members of IEC and IS0 maintain regesters of currently valid international

standards.
ISO/R 527: 1966, Plastics - Determination of tensile properties.
IS0 1302: 1992, Technical drawings - Method of indicating sueace texture.

ISO/IEC 11576: 1994, Information technology - Procedure for the registration of algorithms for the lossless

compression of data.

IEC 950 : 1991, Safety of information technology equipment including electrical business equipment.

4 Definitions

For the purposes of this International Standard, the following definitions apply.

Absolute Frame Number (AFN) : A sequence number, encoded in the Frame.
4.1

4.2 a.c. erase : A process of erasure utilising magnetic fields of decaying intensity.

4.3 Access Point : A point, at the start of a processed record sequence, at which the presentation of Codewords to a

reprocessing algorithm is required to start, regardless of whether the data of interest in a retrieval operation starts at

that point or at a subsequent point.

4.4 Algorithm : A set of rules for transforming the logical representation of data.

4.5 Area ID : An identifier defining the area of the tape and specifying the types of Frame written.

Automatic Track Finding (ATF) : The method by which tracking is achieved.
4.6
---------------------- Page: 12 ----------------------
ISO/IEC 13923: 1996(E)
0 ISO/IEC

4.7 Average Signal Amplitude : The average peak-to-peak value of the output signal from the read head at the

fundamental frequency of the specified physical recording density over a minimum of 7,8 mm of track, exclusive of

missing pulses.

4.8 azimuth : The angular deviation, in degrees, minutes and seconds of arc, made by the mean flux transition line with

the line normal to the centreline of the recorded track.

back surface : The surface of the tape opposite to the magnetic coating which is used to record data.

4.9
4.10 byte : An ordered set of bits acted upon as a unit.
4.11 cartridge : A case containing magnetic tape stored on twin hubs.
4.12 Channel bit : A bit after 8-10 transformation.

4.13 Codeword : A word which is generated by a processing algorithm. The number of bits in a Codeword is variable, and

is not defined by this International Standard.

4.14 Data Format ID : An identifier specifying which data format is being used on the tape.

Early Warning Point (EWP) : A point along the length of the tape at which warning is given of the approach, in the

4.15

forward direction of tape motion, of the partition boundary or of the Physical End of Tape.

4.16 End of Data (EOD) : The point on the tape at the end of the group which contains the last user data.

4.17 Entity : A unit of recorded data, comprising a Processed Record Sequence preceded by housekeeping information.

4.18 Error Correcting Code (ECC) : A mathematical computation yielding check bytes used for the detection and cor-

rection of errors.

4.19 flux transition position : That point which exhibits maximum free-space flux density normal to the tape surface.

4.20 flux transition spacing : The distance along a track between successive flux transitions.

4.21 Frame : A pair of adjacent tracks with azimuths of opposite polarity, in which the track with the positive azimuth

precedes that with the negative azimuth.

4.22 Housekeeping Frame : A Frame which contains no user data and which is identified as such by the values in the data

fields therein.

4.23 Logical Beginning of Tape (LBOT) : The point along the length of the tape where a recording of data for

interchange commences.

4.24 magnetic tape : A tape which will accept and retain the magnetic signals intended for input, output and storage

purposes on computers and associated equipment

4.25 Master Standard Amplitude Calibration Tape : A pre-recorded tape on which the standard signal amplitudes have

been recorded in the tracks of positive azimuth, 21 pm wide, recorded at a track pitch of 27,2 m, on an a.c. erased

tape.

Note 1 - The tape includes recordings made at 83,3 ftpmm, 333,3 ftpmm, 500 ftpmm, 1 000,O ftpmm and 1 499,9 ftpmm.

Note 2 - The Master Standard Amplitude Calibration Tape has been established by Reliability Centre for JZlectronic Components of

Japan (RCJ).
---------------------- Page: 13 ----------------------
0 ISO/IEC
ISO/IEC 13923:1996(E)

4.26 Master Standard Reference Tape : A tape selected as the standard for Reference Recording Field, Signal Ampli-

tude, Resolution, Overwrite and Signal-to-Noise Ratio.
Note 3 - The Master Standard Reference Tape has been established by RCJ.

: In the plot of Average Signal Amplitude against the recording field at the physical

4.27 Optimum Recording Field

recording density of 2 999,9 ftpmm, the field that causes the maximum Average Signal Amplitude.

: The point along the length of a magnetic tape at which partition 1 ends and partition 0

4.28 Partition Boundary
commences.

4.29 Physical Beginning of Tape (PBOT) : The point where the leader tape is joined to the magnetic tape.

Physical End of Tape (PEOT) : The point where the trailer tape is joined to the magnetic tape.

4.30

physical recording density : The number of recorded flux transitions per unit length of track, expressed in flux

4.31
transitions per millimetre (ftpmm).

4.32 pre-recording condition (see annex F) : The recording levels above which a tape intended for interchange shall not

previously have been recorded.
4.33 processing : The use of an algorithm to transform host data into Codewords.

4.34 processed data : A sequence of Codewords which results from the application of processing to data.

4.35 Processed Record : A sequence of Codewords which results from the application of processing to an Unprocessed

Record.

: A sequence of one or more Processed Records which starts on an &bit boundary and

4.36 Processed Record Sequence
ends on a subsequent &bit boundary.
record : Related data treated as a unit of information.
4.37

Reference Recording Field : The Optimum Recording Field of the Master Standard Reference Tape.

4.38

reprocessing : The use of an algorithm to transform Codewords into data as required by the host.

4.39

4.40 Secondary Standard Amplitude Calibration Tape : A tape pre-recorded as defined for the Master Standard

Amplitude Calibration Tape; the outputs are known and stated in relation to those of the Master Standard Amplitude

Calibration Tape.

Note 4 - Secondary Standard Amplitude Calibration Tapes can be ordered from RCJ, l-l- 12 Hachiman-cho, Higashikurume,

Tokyo 203, Japan, under Part Number JCM 6129 until the year 2005. It is intended that these be used for calibrating tertiary

reference tapes for use in routine calibration.

Secondary Standard Reference Tape : A tape the performance of which is known and stated in relation to that of the

4.41
Master Standard Reference Tape.

Note 5 - Secondary Standard Reference Tapes can be ordered from RCJ, 1- 1- 12 Hachiman-cho, Higashikurume, Toyko 203, Japan,

under Part Number JRM 6129 until the year 2005. It is intended that these be used for calibrating tertiary reference tapes for use in

routine calibration.

4e42 Separator Mark : A record containing no user data, which is used to separate data.

4.43 Standard Reference Amplitude : The Average Signal Amplitude from the tracks of positive azimuth of the Master

Standard Amplitude Calibration Tape at a specified physical recording density.
---------------------- Page: 14 ----------------------
ISO/IEC 13923: 1996(E)
0 ISO/IEC

4.44 Tape Reference Edge : The bottom edge of the tape when viewing the recording side of the tape, with the PEOT to

the observer’s right.

4.45 Test Recording Current : The current that produces the Reference Recording Field.

4.46 track : A diagonally positioned area on the tape along which a series of magnetic signals may be recorded.

4.47 unprocessed data : Data which has not been subjected to processing.

4.48 Unprocessed Record : A record of unprocessed data, comprising an integral number of bytes.

4.49 Virtual End of Tape (VEOT) : The point along the length of the magnetic tape within partition 1 which defines the

end of the part of partition 1 which is usable for recording data for interchange.

5 Environment and safety

Unless otherwise stated, the conditions specified below refer to the ambient conditions of the air immediately surrounding the

cartridge.
5.1 Testing environment

Unless otherwise stated tests and measurements made on the tape cartridge to check the requirements of this International

Standard shall be carried out under the following conditions:
temperature : 23 “C t 2 “C
relative humidity : 40 % to 60 %
conditioning period before testing : 24 h
5.2 Operating environment

Cartridges used for data interchange shall be capable of operating under the following conditions:

: 5 “C to 45 “C
temperature
relative humidity : 20 % to 80 %
: 26 “C max.
wet bulb temperature
There shall be no deposit of moisture on or in the cartridge.
Conditioning before operating:

If a cartridge has been exposed during storage and/or transportation to a condition outside the above values, before use the

cartridge shall be conditioned in the operating environment for a time at least equal to the period during which it has been out

of the operating environment, up to a maximum of 24 h.
Note 6 - Rapid variations of temperature should be avoided.
5.3 Storage environment

For long-term or archival storage of cartridges the following conditions shall be observed:

temperature : 5 “C to 32 “C
relative humidity : 20 % to 60 %
wet bulb temperature : 26 “C max.

The stray magnetic field at any point on the tape shall not exceed 4 000 A/m. There shall be no deposit of moisture on or in the

cartridge.
5.4 Transportation

Recommended limits for the environment to which a cartridge may be subjected during transportation, and the precautions to

be taken to minimize the possibility of damage, are provided in annex J.
---------------------- Page: 15 ----------------------
0 ISO/IEC
ISO/IEC 13923:1996(E)
5.5 Safety
The cartridge and its components shall satisfy the requirements of IEC 950.
56 . Flammability

The cartridge and its components shall be made from materials, which if ignited from a match flame, do not continue to burn

in a still carbon dioxide atmosphere.
---------------------- Page: 16 ----------------------
0 ISO/IEC ISO/IEC 13923:1996(E)
Section 2 - Requirements for the case
Dimensional and mechanical characteristics of the case
. General
The case of the cartridge shall comprise
an upper half,
a lower half,
a slider movably mounted on the lower half,
a lid pivotally mounted on the upper half.

In the drawings, using third angle projection, an embodiment of the cartridge is shown a

...

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