ISO/IEC 22051:2002

INTERNATIONAL ISO/IEC
STANDARD 22051
First edition
2002-10-01
Information technology — Data interchange
on 12,7 mm, 448-track magnetic tape
cartridges — SDLT1 format
Technologies de l'information — Échange de données sur cartouche à
bande magnétique 12,7 mm, 448 pistes — Format SDLT1

Reference number
©
ISO/IEC 2002
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©  ISO/IEC 2002
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
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© ISO/IEC 2002 – All rights reserved
ii
Contents
1 Scope 1
2 Conformance 1
2.1 Magnetic tape cartridges 1
2.2 Generating systems 1
2.3 Receiving systems 1
3 Normative references 1
4 Terms and definitions 1
4.1 back surface 1
4.2 Beginning-Of-Tape marker (BOT) 1
4.3 block 2
4.4 byte 2
4.5 cartridge 2
4.6 Cyclic Redundancy Check (CRC) character 2
4.7 Error-Detecting Code (EDC) 2
4.8 End-Of-Tape marker (EOT) 2
4.9 Entity 2
4.10 Error-Correcting Code (ECC) 2
4.11 Envelope 2
4.12 Envelope size 2
4.13 flux transition position 2
4.14 flux transition spacing 2
4.15 logical track 2
4.16 magnetic tape 2
4.17 Master Standard Reference Tape 2
4.18 object 2
4.19 page 2
4.20 recording density 2
4.21 physical track 2
4.22 Record 3
4.23 Reference Edge 3
4.24 Reference Field 3
4.25 Secondary Standard Reference Tape 3
4.26 Standard Reference Amplitude (SRA) 3
4.27 Standard Reference Current 3
4.28 Test Recording Current 3
4.29 Typical Field 3
5 Conventions and notations 3
5.1 Representation of numbers 3
5.2 Dimensions 3
5.3 Names 3
5.4 Acronyms 3
6 Environment and safety 4
6.1 Cartridge and tape testing environment 4
6.2 Cartridge operating environment 4
6.3 Cartridge storage environment 4
6.4 Safety 4
6.5 Flammability 4
6.6 Transportation 4
© ISO/IEC 2002 – All rights reserved
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Section 2 - Requirements for the unrecorded tape 5
7 Mechanical and electrical requirements 5
7.1 Material 5
7.2 Tape length 5
7.3 Tape width 5
7.4 Tape thickness 5
7.5 Discontinuity 5
7.6 Longitudinal curvature 5
7.6.1 Requirements 5
7.6.2 Procedure 5
7.7 Out-of-Plane distortions 5
7.8 Cupping 5
7.9 Roughness of the coating surfaces 6
7.9.1 Roughness of the back coating surface 6
7.9.2 Roughness of the magnetic coating surface 6
7.10 Coating adhesion 6
7.11 Layer-to-layer adhesion 6
7.11.1 Requirements 6
7.11.2 Procedure 6
7.12 Modulus of elasticity 7
7.12.1 Requirement 7
7.12.2 Procedure 7
7.13 Flexural rigidity 8
7.13.1 Requirement 8
7.13.2 Procedure 8
7.14 Tensile yield force 8
7.14.1 Procedure 8
7.15 Electrical resistance 8
7.15.1 Requirement 8
7.15.2 Procedure 8
7.16 Inhibitor tape 9
7.17 Light transmittance of the tape and the leader 9
7.18 Abrasivity 9
7.19 Coefficient of dynamic friction 9
7.19.1 Requirements 9
7.19.2 Procedure for the measurement of the friction between the magnetic surface and the back surface 9
7.19.3 Procedure for the measurement of the friction between the magnetic surface or the back surface and calcium
titanate ceramic 10
7.20 Servo 10
7.20.1 Servo Bands 10
7.20.2 Servo Tracks 11
7.20.3 Signal 11
7.20.4 Signal-to Noise Ratio 11
7.20.5 Missing servo mark 11
8 Magnetic recording characteristics 12
© ISO/IEC 2002 – All rights reserved
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8.1 Typical Field 13
8.2 Signal amplitude 13
8.3 Resolution 13
8.4 Overwrite 13
8.4.1 Requirement 13
9 Tape quality 13
9.1 Missing pulses 13
9.1.1 Requirement 13
9.2 Missing pulse zone 13
9.2.1 Requirement 13
9.3 Tape durability 13
Section 3 - Mechanical specifications of the tape cartridge 14
10 General 14
10.1 Bottom side and right side 14
10.2 Back side and left side 15
10.3 Tape reel 16
10.4 Tape leader 17
10.5 Front side 18
10.6 Operation of the cartridge 18
10.7 Tape winding 19
10.8 Moment of inertia 19
10.9 Material 19
Section 4 - Requirements for an interchanged tape 29
11 Tape format 29
11.1 Reference Edge 29
11.2 Direction of recording 29
11.3 Tape layout 29
11.3.1 Data Area 29
11.3.2 Forward Alignment and Directory Area 31
11.3.3 Reverse Alignment Area at EOT 32
12 Data format 33
12.1 Record 33
12.2 Data Bytes 33
12.3 Data Field 33
12.3.1 Pages 34
12.3.2 Pad Bytes 34
12.3.3 Page layout 34
12.3.4 MAP entries 34
12.3.5 EDC 35
12.4 Data Blocks 35
12.4.1 Control Field 1 (CF1) 36
12.4.2 Control Field 2 (CF2) 37
12.4.3 CRC 39
13 Method of recording 39
13.1 Physical recording density 40
13.2 Channel bit cell length 40
© ISO/IEC 2002 – All rights reserved
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13.2.1 Average Channel bit cell length 40
13.2.2 Long-term average Channel bit cell length 40
13.2.3 Short-term average Channel bit cell length 40
13.3 Read signal amplitude 40
13.4 Channel skew 40
14 Block Recording Format 41
14.1 Scrambler 41
14.2 Modulation 41
14.2.1 Modulation process 41
14.2.2 Modulated Data Group 42
14.3 Precoder 42
14.4 Recording Data Block 43
14.4.1 Preamble 43
14.4.2 Sync 43
15 Types and Use of Blocks 43
15.1 Types of Blocks 43
15.2 Use of blocks 43
15.2.1 Track ID Start Blocks 43
15.2.2 End of Track Blocks (EOTR) 44
15.2.3 End of Data of Data Blocks (EOD) 44
15.2.4 ECC Blocks 44
15.2.5 Track ID End Blocks 44
16 Format of Entities 44
17 Format of Envelopes 44
18 Error handling 44
Annexes
A - Measurement of light transmittance 45
B - Procedure for the measurement of abrasivity 48
C - Generation of the Data Block CRCs 50
D - Generation of page CRCs 51
E - ECC generation 52
F - Allocation of Physical Tracks to Logical Tracks 55
G - Recommendations for transportation 56
H - Inhibitor tape 57
J - Recommendations on tape durability 58
K - Handling guidelines 59
© ISO/IEC 2002 – All rights reserved
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Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the
specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the
development of International Standards through technical committees established by the respective organization to deal with
particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other
international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the
field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of the joint technical committee is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights.
ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 22051 was prepared by ECMA (as ECMA-320) 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 ISO and IEC.
Annexes A to F form a normative part of this International Standard. Annexes G to K are for information only.

© ISO/IEC 2002 – All rights reserved
vii
INTERNATIONAL STANDARD ISO/IEC 22051:2002(E)

Information technology — Data interchange on 12,7 mm, 448-track
magnetic tape cartridges — SDLT1 format
Section 1 - General
1 Scope
This International Standard specifies the physical and magnetic characteristics of a 12,7 mm wide, 448-track magnetic tape
cartridge, to enable physical interchangeability of such cartridges between drives. It also specifies the quality of the recorded
signals, a format - called Super Digital Linear Tape 1 (SDLT 1) - and a recording method, thereby allowing data interchange
between drives. Together with a labelling standard, for instance ISO 1001 for Magnetic Tape Labelling, it allows full data
interchange by means of such magnetic tape cartridges.
2 Conformance
2.1 Magnetic tape cartridges
A magnetic tape cartridge shall be in conformance with this International Standard if it satisfies all mandatory requirements of
this International Standard. The tape requirements shall be satisfied throughout the extent of the tape.
2.2 Generating systems
A system generating a magnetic tape cartridge for interchange shall be in conformance with this International Standard if all
the recordings that it makes on a tape according to 2.1 meet the mandatory requirements of this International Standard.
In addition, a claim of conformance shall state
− whether or not one, or more registered algorithm(s) are implemented within the system,
− the registered identification number(s) of the implemented compression algorithm(s).
2.3 Receiving systems
A system receiving a magnetic tape cartridge for interchange shall be in conformance with this International Standard if it is
able to handle any recording made on a tape according to 2.1.
In addition, a claim of conformance shall state
− whether or not one, or more de-compression algorithm(s) are implemented within the system, and are able to be applied to
de-compress data prior to making such data available to the host,
− the registered identification number(s) of the implemented compression algorithm(s).
3 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this
International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not
apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the
normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 1001:1986, Information processing — File structure and labelling of magnetic tapes for information interchange
ISO 1302:2002, Geometrical Product Specifications (GPS) — Indication of surface texture in technical product documentation
ISO/IEC 11576:1994, Information technology — Procedure for the registration of algorithms for the lossless compression of
data
4 Terms and definitions
For the purpose of this International Standard, the following terms and definitions apply.
4.1 back surface
The surface of the tape opposite the magnetic coating which is used to record data.
4.2 Beginning-Of-Tape marker (BOT)
A hole punched on the centreline of the tape towards the end nearest to the leader.
© ISO/IEC 2002 – All rights reserved

4.3 block
A set of contiguous bytes recorded on a physical track and considered as a unit.
4.4 byte
An ordered set of bits acted upon as a unit.
NOTE - In this International Standard, all bytes are 8-bit bytes.
4.5 cartridge
A case containing a single supply reel of 12,7 mm wide magnetic tape with a leader attached at the outer end.
4.6 Cyclic Redundancy Check (CRC) character
A 64-bit character, generated by a mathematical computation, used for error detection.
4.7 Error-Detecting Code (EDC)
A mathematical computation yielding check bytes used for error detection.
4.8 End-Of-Tape marker (EOT)
A hole punched on the centreline of the tape towards the end farthest from the leader.
4.9 Entity
A group of twenty blocks treated as a logical unit.
4.10 Error-Correcting Code (ECC)
A mathematical computation yielding check bytes used for the correction of errors detected by the CRC and the EDC.
4.11 Envelope
A group of Entities.
4.12 Envelope size
The number of Entities in an Envelope.
4.13 flux transition position
The point that exhibits the maximum free-space flux density normal to the tape surface.
4.14 flux transition spacing
The distance on the magnetic tape between successive flux transitions.
4.15 logical track
A group of eight physical tracks that are written or read simultaneously.
4.16 magnetic tape
A tape that accepts and retains magnetic signals intended for input, output, and storage purposes on computers and associated
equipment.
4.17 Master Standard Reference Tape
A tape selected as the standard for Reference Field, signal amplitude, resolution, and overwrite characteristics.
NOTE - The Master Standard Reference Tape has been established by the Quantum Corporation.
4.18 object
A Record or a page of type Tape Mark.
4.19 page
A logical division of a block.
4.20 recording density
The number of recorded flux transitions per unit length of track.
4.21 physical track
A longitudinal area on the tape along which a series of magnetic signals can be recorded.
© ISO/IEC 2002 – All rights reserved

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