ISO/IEC 15757:1998

INTERNATIONAL ISO/IEC
STANDARD 15757
First edition
1998-07-15
Information technology — Data interchange
on 8 mm wide magnetic tape cartridge —
Helical scan recording — DA-2 format
Technologies de l'information — Échange de données sur cartouche de
bande magnétique de 8 mm de large — Enregistrement par balayage en
spirale — Format DA-2
Reference number
B C
Contents
Section 1 - General 1
1 Scope 1
2 Conformance 1
2.1 Magnetic tape cartridges 1
2.2 Generating drive 1
2.3 Receiving drive 1
3 Normative references 1
4 Definitions 1
4.1 a.c. erase: 2
4.2 algorithm 2
4.3 append point 2
4.4 Average Signal Amplitude 2
4.5 azimuth 2
4.6 back surface 2
4.7 bit cell 2
4.8 byte 2
4.9 cartridge 2
4.10 Channel bit 2
4.11 Cluster 2
4.12 Cyclic Redundancy Check (CRC) character 2
4.13 Digital Sum Variation (DSV) 2
4.14 Error Correcting Code (ECC) 2
4.15 File Mark 2
4.16 flux transition spacing 2
4.17 Logical Beginning of Partition (LBOP) 2
4.18 Logical Block 2
4.19 magnetic tape 2
©  ISO/IEC 1998
All rights 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 micro-
film, without permission in writing from the publisher.
ISO/IEC Copyright Office • Case postale 56 • CH-1211 Genève 20 • Switzerland
Printed in Switzerland
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ISO/IEC ISO/IEC 15757:1998 (E)
4.20 Master Standard Reference Tape 2
4.21 Partition 2
4.22 Physical Beginning of Partition (PBOP) 2
4.23 Physical Beginning of Tape (PBOT) 2
4.24 Physical End of Partition (PEOP) 2
4.25 Physical End of Tape (PEOT) 2
4.26 physical recording density 2
4.27 Read Back Check (RBC) 2
4.28 Reference Field 2
4.29 Secondary Standard Reference Tape (SSRT) 2
4.30 Set Mark 3
4.31 Standard Reference Amplitude (SRA) 3
4.32 Standard Reference Current (Ir) 3
4.33 Tape Reference Edge 3
4.34 Test Recording Current (TRC) 3
4.35 Track 3
4.36 Typical Field 3
5 Conventions and Notations 3
5.1 Representation of numbers 3
5.2 Names 3
5.3 Reserved fields 3
6 Acronyms 3
7 Environment and Safety 4
7.1 Testing environment 4
7.2 Operating environment 4
7.3 Storage environment 4
7.4 Transportation 4
7.5 Safety 4
7.6 Flammability 4
Section 2 - Requirements for the case 5
8 Dimensional and mechanical characteristics of the case 5
8.1 General 5
8.2 Overall dimension 5
8.3 Holding areas 6
8.4 Cartridge insertion 6
8.5 Window 7
8.6 Loading grips 7
8.7 Label areas 7
8.8 Datum areas and datum holes 7
8.9 Support areas 8
8.10 Recognition holes 9
8.11 Write-inhibit hole 9
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ISO/IEC
8.12 Pre-positioning surfaces 10
8.13 Cartridge lid 10
8.14 Cartridge reel lock 11
8.15 Reel access holes 12
8.16 Interface between the reels and the drive spindles 12
8.17 Light path 13
8.18 Position of the tape in the case 14
8.19 Tape path zone 14
8.20 Tape access cavity 14
8.21 Tape access cavity clearance requirements 15
Section 3 - Requirements for the Unrecorded Tape 31
9 Mechanical, physical and dimensional characteristics of the tape 31
9.1 Materials 31
9.2 Tape length 31
9.2.1 Length of magnetic tape 31
9.2.2 Length of leader and trailer tapes 31
9.2.3 Splicing tape 31
9.3 Width 31
9.3.1 Width of magnetic, leader and trailer tape 31
9.3.2 Width and position of splicing tape 31
9.4 Discontinuities 31
9.5 Thickness 31
9.5.1 Thickness of magnetic tape 31
9.5.2 Thickness of leader and trailer tape 31
9.5.3 Thickness of splice tape 31
9.6 Longitudinal curvature 32
9.7 Cupping 32
9.8 Coating adhesion 32
9.9 Layer-to-layer adhesion 33
9.10 Tensile strength 33
9.10.1 Breaking strength 33
9.10.2 Yield strength 33
9.11 Residual elongation 33
9.12 Electrical resistance of the recording surface 34
9.13 Tape winding 34
9.14 Light transmittance of tape 34
9.15 Data cartridge recognition stripe 34
10 Magnetic recording characteristics 35
10.1 Test conditions 35
10.2 Typical Field 35
10.3 Signal Amplitude 35
10.4 Resolution 35
10.5 Narrow-band Signal-to-Noise Ratio 36
10.6 Ease of erasure 36
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ISO/IEC ISO/IEC 15757:1998 (E)
10.7 Tape quality 36
10.7.1 Missing pulses 36
10.7.2 Missing pulse zone 36
10.7.3 Overwrite 36
Section 4 - Requirements for an Interchanged Tape 37
11 Format of a track pair 37
11.1 General 37
11.2 Physical block format 38
11.2.1 General 38
11.2.2 Common header fields 39
11.2.3 Data Block 40
11.2.4 Erase Block 41
11.2.5 Diagnostic Block 41
11.2.6 Physical Beginning of Partition (PBOP) Block 41
11.2.7 Long File Mark Block 42
11.2.8 Short File Mark Block 42
11.2.9 Logical Beginning of Partition (LBOP) Block 43
11.2.10 Set Mark Block 44
11.2.11 Gap Block 45
11.2.12 End of Data (EOD) Block 45
11.2.13 Recorded patterns 45
11.3 Search field format 46
11.3.1 Search field data 46
11.3.2 Search field ECC 47
11.3.3 Search field recording patterns 48
11.4 Servo area 49
11.5 Track layout 50
12 Method of recording 51
12.1 Physical Recording Density 51
12.1.1 Long Term Average Bit Cell Length 51
12.1.2 Short Term Average Bit Cell Length 52
12.1.3 Rate of Change 52
12.2 Bit Shift 52
12.3 Amplitude of Data Signals 52
13 Track geometry 52
13.1 General 52
13.2 Average track pitch - C 52
13.3 Track pitch variation 53
13.4 Track width - B 53
13.5 Track angle - A 53
13.6 Track length -E 53
13.7 Guard band - F 53
13.8 Azimuth angles 53
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ISO/IEC
13.9 Track linearity 53
14 Layout of a tape 53
14.1 General 53
14.2 Tape History Log (THL) 54
14.3 Physical Beginning of Partition 54
14.4 Logical Beginning of Partition 54
14.5 Data area 54
14.5.1 General 54
14.5.2 Short File Mark 54
14.5.3 Long File Mark 54
14.5.4 Set Mark 54
14.6 End of Data 54
14.7 Physical End of Partition (PEOP) 54
Annexes
A - Measurement of Light Transmittance of Tape and Leaders 55
B - Measurement of bit shift 58
C - Representation of 8-bit bytes by 10-bit patterns 60
D - Generation of Data Area CRC 67
E - Generation of ECC 68
F - Generation of Logical Block CRC 70
G - Generation of Hamming Code ECC 71
H - Generation of Search Field CRC 72
J - Randomization 73
K - Recommendations for transportation 74
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ISO/IEC ISO/IEC 15757:1998 (E)
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. 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.
International Standard ISO/IEC 15757 was prepared by ECMA (as ECMA-249) 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 J form an integral part of this International Standard. Annex K is for information only.
vii

INTERNATIONAL STANDARD ISO/IEC ISO/IEC 15757:1998 (E)
Information technology — Data interchange on 8 mm wide magnetic tape
cartridge — Helical scan recording — DA-2 format
Section 1 - General
1Scope
This International Standard specifies the physical and magnetic characteristics of a 8 mm wide magnetic tape cartridge to
enable physical interchange 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.
Information interchange between systems also requires, at a minimum, agreement between the interchange parties upon the
interchange code(s) and the specifications of the structure and labelling of the information on the interchanged cartridge.
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 throughout the extent of the tape.
2.2 Generating drive
A drive generating a magnetic tape cartridge for interchange shall be entitled to claim conformance with this International
Standard if all the recordings that it makes on a tape meet the mandatory requirements of this International Standard. A claim
of conformance shall state whether or not one or more registered compression algorithm(s) are implemented within the system
to process data from the host prior to allocating data to physical blocks.
2.3 Receiving drive
A system receiving a magnetic tape cartridge for interchange shall be entitled to claim conformance with the International
Standard if it is able to handle any recording on this tape according to this International Standard. A receiving drive shall be
able to recognize the use of a data compression algorithm and make the algorithm registration number available to the host.
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 ISO maintain registers of currently valid International
Standards.
ISO 527-1:1993, Plastics — Determination of tensile properties — Part 1: General principles.
ISO 1302:1992, Technical drawings — Method of indicating surface texture.
ISO/IEC 11576:1995, Information technology — Procedure for the registration of algorithms for the lossless compression
of data.
IEC 950:1991, Safety of information technology equipment.
4 Definitions
For the purposes of this International Standard, the following definitions apply.

ISO/IEC
4.1 a.c. erase: A process of erasure utilizing alternating magnetic fields of decaying intensity.
4.2 algorithm: A set of rules for transforming the logical representation of data.
4.3 append point: The first physical block on the first track 1 following the two gap stripes that precede a Long File
Mark, Set Mark, or EOD and follow the last track pair containing any portion of a logical block
4.4 Average Signal Amplitude: The average peak-to-peak value of the signal of a read head measured over a
minimum of 3 000 flux transitions, exclusive of missing pulses.
4.5 azimuth: The angular deviation, in degrees of arc, of the recorded flux transitions on a track from a line normal to
the track centreline.
4.6 back surface: The surface of the tape opposite to the magnetic coating used to record data.
4.7 bit cell: A distance along the track allocated for the recording of a channel bit.
4.8 byte: An ordered set of bits acted upon as a unit.
4.9 cartridge: A case containing magnetic tape stored on twin reels.
4.10 Channel bit: A bit after 8-10 transformation.
4.11 Cluster: A group of sequential blocks of the same block type.
4.12 Cyclic Redundancy Check (CRC) character: A character derived from information contained in data
bytes that are used for error detection.
4.13 Digital Sum Variation (DSV): The integrated value of Channel bits taken from the beginning of each track
counting a ONE as +1 and a ZERO as -1.
4.14 Error Correcting Code (ECC): A mathematical procedure yielding bytes used for the detection and
correction of errors.
4.15 File Mark:
A mark recorded on the tape at the request of the host system to separate files or to provide a splice
point. This format provides for Long or Short File Marks.
4.16 flux transition spacing: The distance along a track between successive flux transitions.
4.17 Logical Beginning of Partition (LBOP): The point in a partition where a recording of data for
interchange commences.
4.18 Logical Block: Information (data, file marks, or set marks) sent from the host to the tape drive to be recorded.
4.19 magnetic tape: A tape that accepts and retains magnetic signals intended for input, output, and storage of data
for information processing.
4.20 Master Standard Reference Tape: A tape selected as the standard for Signal Amplitude, Typical Field,
Overwrite and Resolution.
NOTE - The Master Standard Reference Tape has been established by Pericomp Corporation.
4.21 Partition: A formatted length of tape used to record data. Partitions are used to divide the tape into shorter
updatable areas.
4.22 Physical Beginning of Partition (PBOP): The point along the length of tape at which a partition begins.
4.23 Physical Beginning of Tape (PBOT): The transition from the tape leader to the opaque area of the splice
by which the translucent leader tape is joined to the magnetic tape.
4.24 Physical End of Partition (PEOP): The point along the length of tape at which a partition ends.
4.25 Physical End of Tape (PEOT): The transition from the opaque area of the splice to the translucent trailer
tape.
4.26 physical recording density: The number of recorded flux transitions per unit length of track, expressed in
flux transitions per millimetre (ftpmm).
4.27 Read Back Check (RBC): A Read Back Check occurs when, while writing, the data is read by trailing heads
and checked for errors.
4.28 Reference Field: The Typical Field of the Master Standard Reference Tape.
4.29 Secondary Standard Reference Tape (SSRT): A tape the performance of which is known and stated in
relation to that of the Master Standard Reference Tape.
NOTE - Secondary Standard Reference Tapes can be ordered under the Part Number SSRT/M.AME/PC97, from Pericomp Corporation, 14 Huron Drive,
Natick, MA 01760, USA.
ISO/IEC ISO/IEC 15757:1998 (E)
In principle, such tapes will be available for a period of 10 years from the first edition of this International Standard. However, by agreement between
ISO/IEC JTC 1 and Pericomp, this period may be shortened or extended to take account of demand for such tapes.
It is intended that these be used for calibrating Tertiary Reference Tapes for use in routine calibration.
4.30 Set Mark: A mark recorded on the tape at the request of the host system to separate a set of data or to provide a
splice point.
4.31 Standard Reference Amplitude (SRA): The Average Signal Amplitude derived from the Master Standard
Reference Tape, using the Test Recording Current at 3 819 ftpmm.
4.32 Standard Reference Current (Ir): The current that produces the Reference Field.
4.33 Tape Reference Edge: The lower edge of tape as seen when viewing the recording surface of the tape with the
supply reel to the observer’s right.
4.34 Test Recording Current (TRC): The current used to record the SRA. The TRC is 1,5 times the Standard
Reference Current.
4.35 Track: A diagonally positioned area on the tape along which a series of magnetic transitions may be recorded.
4.36 Typical Field: In the plot of the Average Signal Amplitude against the recording field at the physical recording
density of 3 819 ftpmm, the minimum field that causes an Average Signal Amplitude equal to 90% of the maximum Average
Signal Amplitude.
5 Conventions and Notations
5.1 Representation of numbers
• A measured value is rounded off to the least significant digit of the corresponding specified value. It implies that a specific
value of 1,26 with a positive tolerance of +0,01, and a negative tolerance of -0,02 allows a range of measured values from
1,235 to 1,275.
• Letters and digits in parentheses represent numbers in hexadecimal notation.
• The setting of a bit is denoted by ZERO or ONE.
• Numbers in binary notation and bit combinations are represented by strings of digits 0 and 1.
• Numbers in binary notation and bit combinations are shown with the most significant byte to the left, and with the most
significant bit in each byte to the left.
• Negative values of numbers in binary notation are given in Two’s complement.
• In each field the data is processed so that the most significant byte (byte 0) is processed first. Within each byte the most
significant bit (numbered 7 in an 8-bit byte) is processed first, least significant bit is numbered 0 and is processed last. This
order of processing applies also to the data input to the Error Detection and Correction circuits and to their output, unless
otherwise stated.
5.2 Names
The names of entities, e.g. specific tracks, fields, etc., are given with a capital initial.
5.3 Reserved fields
Fields marked resv are reserved for future format extensions and all bits in these fields shall be set to ZERO.
6 Acronyms
CRC Cyclic Redundancy Check
BID Block Identifier
ECC Error Correction Code
EOD End of Data
FID File Identifier
LBOP Logical Beginning of Partition
LID Logical Block Identifier
lsb Least Significant Bit
LSB Least Significant Byte
msb Most Significant Bit
MSB Most significant Byte
PBOP Physical Beginning of Partition

ISO/IEC
PBOT Physical Beginning of Tape
PEOP Physical End of Partition
PEOT Physical End of Tape
PID Physical Identifier
RBC Read Back Check
SID Stream Identifier
SMID Set Mark Identifier
SRA Standard Reference Amplitude
SSRT Secondary Standard Reference Tape
TRC Test Recording Current
7 Environment and Safety
The conditions specified below refer to the ambient conditions immediately surrounding the cartridge.
Cartridges exposed to environments outside these limits may still be able to function usefully; however, such exposure may
cause permanent damage.
7.1 Testing environment
Unless otherwise specified, tests and measurements made on the cartridge to check the requirements of this International
Standard shall be carried out under the following conditions
temperature: 23°C ± 2°C
relative humidity: 40 % to 60 %
conditioning period
before testing: 24 h
7.2 Operating environment
Cartridges used for data interchange shall be capable of operating under the following conditions
temperature: 5°C to 45°C
relative humidity: 20 % to 80 %
wet bulb temperature: 26°C max.
The average temperature of the air immediately surrounding the tape shall not exceed 45°C.
Conditioning before operating: If a cartridge has been exposed during storage and/or transportation to conditions 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.
7.3 Storage environment
The following conditions shall be observed during storage
temperature: 5°C to 32°C
relative humidity: 20 % to 60 %
stray magnetic field: shall not exceed 4 000 A/m at any point on the tape.
There shall be no deposit of moisture on or in the cartridge.
7.4 Transportation
Recommended limits for the environments 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 K.
7.5 Safety
The cartridge shall satisfy the safety requirements of Standard IEC 950 when used in the intended manner or in any foreseeable
use in an information processing system.
7.6 Flammability
The cartridge shall be made from materials that comply with the flammability class for HB materials, or better, as specified in
Standard IEC 950.
ISO/IEC ISO/IEC 15757:1998 (E)
Section 2 - Requirements for the case
8 Dimensional and mechanical characteristics of the case
8.1 General
The cartridge shall consist of the following elements:
− a case
− recognition holes
− a write inhibit mechanism
− twin reels containing magnetic tape
− a locking mechanism for the reels
Dimensional characteristics are specified for those parameters deemed to be mandatory for interchange and compatible use of
the cartridge. Where there is freedom, of design, only the functional characteristics of the elements described are indicated. In
the figures a typical implementation is represented in third angle projections.
Figure 1 is a perspective view of the cartridge seen from the top.
Figure 2 is a perspective view of the cartridge seen from the bottom.
Figure 3 is a perspective view of Reference Planes X, Y and Z.
Figure 4 shows the front side with the lid closed.
Figure 5 shows the left side with the lid closed.
Figure 6 shows the top side with the lid closed.
Figure 7 shows the right side with the lid closed.
Figure 8 shows the rear side with the lid closed.
Figure 9 shows the bottom side, datum and support areas.
Figure 10 shows the bottom side with the lid removed.
Figure 11 is the enlarged view of the datum and recognition holes.
Figure 12 are the cross-sections through the light path holes, the recognition holes and the write-inhibit hole.
Figure 13 shows details of the lid when closed, rotating and open.
Figure 14 shows the details of the lid release insertion channel.
Figure 15 shows the lid lock release requirements.
Figure 16 shows the reel lock release requirements.
Figure 17 shows the reel unlock force direction.
Figure 18 shows the lid release force direction.
Figure 19 shows the lid opening force direction.
Figure 20 shows the light path and light window.
Figure 21 shows the internal tape path and light path.
Figure 22 shows the cartridge reel and a cross-section view of the cartridge reel.
Figure 23 is a cross-section view of the cartridge reel interface with the drive spindle.
Figure 24 shows the tape access cavity clearance requirements.
The dimension are referred to three orthogonal Reference Planes X, Y and Z (see figure 3).
Plane X is perpendicular to Plane Z and passes through the centres of the Datum Holes A and B.
Plane Y is perpendicular to Plane X and Plane Z and passes through the centre of Datum Hole A.
Datum area A, B and C shall lie in Plane Z.
8.2 Overall dimension (figures 5 and 6)
The length of the case shall be
l = 62,5 mm ± 0,3 mm
The width of the case shall be
l = 95,0 mm ± 0,2 mm
The distance from the top of the case to Plane Z shall be
l = 15,0 mm ± 0,2 mm
The distance from the rear side to Plane X shall be
l = 47,35 mm ± 0,15 mm

ISO/IEC
The distance from the right side to Plane Y shall be
l = 13,0 mm ± 0,1 mm
8.3 Holding areas
The holding areas shown hatched in figure 6 shall be the areas along which the cartridge shall be held down when inserted into
the drive. The distance of the holding areas from Plane X shall be
l = 12,0 mm max.
The width when measured from the edge of the case shall be
l = 3,0 mm min.
8.4 Cartridge insertion
The cartridge shall have asymmetrical features to prevent insertion into the drive in other than the correct orientation. These
consist of an insertion channel, a recess and an incline.
The insertion channel (figures 4 and 14) shall provide for an unobstructed path, when the lid is closed and locked, to unlock the
lid. The distance of the insertion channel from Plane Y shall be
l = 79,7 mm ± 0,2 mm
There shall be a chamfer at the beginning of the insertion channel defined by
l = 1,0 mm ± 0,1 mm
l = 1,5 mm ± 0,1 mm
An additional chamfer further into the insertion channel shall be defined by
l = 0,7 mm ± 0,1 mm
l = 1,0 mm ± 0,1 mm
l = 3,8 mm ± 0,1 mm
The innermost width of the insertion channel shall be
l = 1,0 mm min.
The thickness of the lid shall be
l = 1,2 mm ± 0,1 mm
There shall be a chamfer on the lid defined by
l = 0,8 mm ± 0,1 mm
l = 1,2 mm ± 0,1 mm
The lid shall extend from the case a distance of
l = 0,5 mm ± 0,1 mm
The distance from the left side of the case to the lid lock shall be
l = 0,2 mm ± 0,2 mm
The height of the insertion area shall be
l = 2,3 mm min.
+ 0,2 mm
l = 2,5 mm
- 0,0 mm
The recess is located on the right side of the cartridge. The position and dimensions (figures 5, 7 and 10) shall be defined by
l = 7,5 mm max.
l = 11,0 mm ± 0,2 mm
l = 1,5 mm ± 0,1 mm
ISO/IEC ISO/IEC 15757:1998 (E)
The depth of the recess shall be
l = 1,5 mm ± 0,1 mm
The incline (figure 13a) is part of the lid structure. The distance of the incline from Plane X shall be defined by
+ 0,0 mm
l = 7,7 mm
- 2,5 mm
The angle of the incline shall be
o o
a = 20 ± 1
The incline shall end when it intersects the radius r (see clause 8.13).
8.5 Window (figure 1)
A window may be provided on the top side so that parts of the reels are visible. The window, if provided, shall not extend
beyond the height of the cartridge.
8.6 Loading grips (figures 5 and 7)
The cartridge shall have recessed loading grips on each side to aid an automatic loading mechanism.
The distance from Plane X to the centreline of the loading grip shall be
l = 39,35 mm ± 0,20 mm;
The distance from Plane Z on the bottom side and from the top side shall be
l = 1,5 mm ± 0,1 mm;
The width of the indent shall be
l = 5,0 mm ± 0,3 mm;
The depth of the indent shall be
l = 2,0 mm ± 0,2 mm;
and the angle of the indent
o o
a = 90 ± 5 .
8.7 Label areas (figures 6 and 8)
A portion of the rear side of the cartridge and a portion of the top side of the cartridge may be used for labels. The position and
the size of the labels shall not interfere with the operation or clearance requirements of the cartridge component parts.
The area used for labels on the top side shall not extend beyond the inner edge of the holding areas defined by l and l .
6 7
The position and dimensions of the label area on the rear side shall be defined by
l = 0,5 mm min.
l = 1,5 mm min.
l = 80,0 mm max.
The depth of the label areas shall be 0,3 mm max.
8.8 Datum areas and datum holes
The annular datum areas A, B and C shall lie in Plane Z (see figures 9, 10 and 11). They determine the vertical position of the
cartridge in the drive. Each shall have a diameter d equal to 6,0 mm ± 0,1 mm and be concentric with the respective datum
hole.
The centres of datum holes A and B lie in Plane X.
The centre of the circular datum hole A shall be at the intersection of planes X and Y (see figure 10).
The distance from the centre of datum hole B to Plane Y (see figure 9) shall be
l = 68,0 mm ± 0,1 mm
The distance from the centre of the circular datum hole C to Plane Y (see figure 11) shall be
l = 10,20 mm ± 0,05 mm

ISO/IEC
The distance from the centre of datum hole D to Plane Y (see figure 11) shall be
l = 79,2 mm ± 0,2 mm
The distance from the centres of datum holes C and D to Plane X (see figure 10) shall be
l = 36,35 mm ± 0,08 mm
The thickness of the case in the datum areas shall be
l = 1,2 mm ± 0,1 mm
The diameter at the bottom of datum hole A and datum hole C shall be
l = 2,6 mm min.
The depth of the holes shall be
l = 4,0 mm min.
The upper diameter of datum holes A and C shall be
+ 0,05 mm
l = 3,00 mm
- 0,00 mm
This diameter shall be to a depth of
l = 1,5 mm min.
There shall be a chamfer around the outside of datum hole A and datum hole C defined by
l = 0,3 mm max.
o o
a = 45 ± 1
The width at the bottom of datum holes B and D shall be l .
The depth of the holes shall be l .
The dimensions at the top of the holes shall be
l = 3,5 mm ± 0,1 mm
+ 0,05 mm
l = 3,00 mm
- 0,00 mm
r = 1,75 mm ± 0,05 mm
This width shall be to a depth l .
There shall be a chamfer around the outside of datum holes B and D defined by l and a .
43 3
8.9 Support areas (figure 9)
The cartridge Support areas are shown shaded in figure 9. Support areas A’, B’ and C’ shall be coplanar with Datum areas A, B
and C, respectively, within 0,1 mm. Support area D’ shall be coplanar with Plane Z within 0,15 mm.
The areas within l of the edge of the cartridge shall be recessed from the Support Areas.
l = 0,5 mm ± 0,1 mm
Support areas A’ and B’ shall extend from Plane X towards the front of the case a distance
l = 10,0 mm ± 0,1 mm
Support areas A’ and B’ shall extend from the centre of the Datum holes toward the outside of the case a distance l .
Support areas A’ and B’ shall extend from the centre of the Datum holes toward the inside of the case a distance of
l = 11,0 mm ± 0,1 mm
Support areas A’ and B’ shall extend from Plane X toward the rear of the case a distance of
l = 7,0 mm ± 0,1 mm
ISO/IEC ISO/IEC 15757:1998 (E)
The distance of Support areas C’ and D’ from Plane X shall be
l = 30,0 mm ± 0,1 mm
The dimensions of Support areas C’ and D’ shall be defined by l and
l = 5,5 mm ± 0,1 mm
l = 64,5 mm ± 0,2 mm
8.10 Recognition holes (figures 10, 11 and 12)
There shall be 5 recognition holes numbered 1 to 5 as shown in figure 11.
The centre of recognition hole 1 shall be defined by
l = 43,35 mm ± 0,15 mm
l = 6,4 mm ± 0,1 mm
The centre of recognition hole 2 shall be defined by l and l .
54 57
The centre of recognition hole 3 shall be defined by l and
l = 79,0 mm ± 0,2 mm
The centre of recognition hole 4 shall be defined by
l = 3,7 mm ± 0,1 mm
l = 2,3 mm ± 0,1 mm
The centre of recognition hole 5 shall be defined by l and l .
55 56
All recognition holes shall have the cross-section E-E and F-F shown in figure 12 and shall have a diameter of 3,0 mm ± 0,1
mm.
The depth of a closed recognition hole below Plane Z shall be
+0,3 mm
l = 1,2 mm
- 0,1 mm
The depth of an open recognition hole below Plane Z shall be
l = 5,0 mm min.
One of the cross-sections shows a recognition hole closed by a plug. The other shows one hole with the plug punched out and
the other hole closed by a plug. These plugs shall withstand an applied force of 0,5 N max. without being punched out.
This International Standard prescribes the following states of these holes.
− Recognition hole 1 shall be open.
− Recognition hole 2 shall be open
− Recognition hole 3 shall be open
− Recognition hole 4 shall be closed.
− Recognition hole 5 shall be closed.
8.11 Write-inhibit hole (figures 11 and 12)
The centre of the Write-inhibit hole shall be defined by l and
l = 10,0 mm ± 0,1 mm
The diameter of the hole shall be 3,0 mm ± 0,1 mm.
The depth of a closed Write-inhibit hole below Plane Z shall be l .
The depth of an open Write-inhibit hole below Plane Z shall l
When the Write-inhibit hole is open, recording on the tape is inhibited. When it is closed, recording is enabled.
The case may have a movable element allowing the write-inhibit hole to be opened or closed. If present, this element shall be
such that the state of the write-inhibit hole shall be visible (see figure 8 as an example). The write-inhibit hole closure shall be
constructed to withstand a force of 0,5 N. The force required to open or close the write-inhibit hole shall be between 1 N and
15 N.

ISO/IEC
8.12 Pre-positioning surfaces (figures 4 and 10)
These surfaces determine the position of the cartridge when it is inserted into the drive loading slot.
The distance from Plane Z to the surface on which the tape reference edge rests (figure 4) shall be
+ 0,0 mm
l = 2,4 mm
- 0,1 mm
Positioning of the cartridge relative to Plane Y shall be controlled by the surfaces defined by
l = 1,0 mm ± 0,1 mm
l = 69,0 mm ± 0,2 mm
Positioning of the cartridge relative to Plane X shall be controlled by the surfaces defined by
l = 14,65 mm ± 0,10 mm
The position and angle of the chamfer at the edge of this surface shall be defined by
l = 13,15 mm ± 0,10 mm
o o
a = 45 ± 1
8.13 Cartridge lid (figures 6 and 13)
The cartridge shall have a lid for protection of the tape during handling, storage and transportation. The lid consists of two
parts, the main part and an auxiliary part.
The main part rotates around axis A (see figure 13) the position of which is fixed relative to the case.
The location of axis A shall be defined by
+ 0,05 mm
l = 0,55 mm
- 0,10 mm
l = 7,5 mm ± 0,1 mm
The auxiliary part rotates around axis B the position of which is fixed relative to the main part of the lid and moves with it.
When the lid is in the closed position, the location of axis B shall be defined by
l = 7,0 mm ± 0,1 mm
l = 10,1 mm ± 0,1 mm
The rotation of the auxiliary part is controlled by a cam at each end to give the path indicated in figure 13.
The auxiliary part, when fully opened, shall allow a clearance of
l = 14,8 mm min.
+ 0,2 mm
l = 11,5 mm
- 0,0 mm
l = 1,2 mm ± 0,1 mm
When the lid is completely open, neither part shall extend above a plane located l above and parallel to Plane Z.
l = 22,3 mm max.
The angle to the bottom of the lid from Plane Z when the lid is completely open shall be
o
+ 1
o
a = 85
o
- 2
When the lid is in a partially open position, neither part shall extend above a plane located l above and parallel to Plane Z.
l = 22,5 mm max.
The path of the top of the lid as it opens shall be defined by
r = 14,9 mm max.
ISO/IEC ISO/IEC 15757:1998 (E)
The start point of the incline on the case that meets the lid (cross-section B-B in figure 6) shall be defined by
l = 8,4 mm max.
The height of the lid from Plane Z (figure 13) shall be
+ 0,0 mm
l = 15,2 mm
- 0,5 mm
The front of the lid measured from Plane X shall be
+ 0,0 mm
l = 15,3 mm
- 0,3 mm
The inside of the lid shall provide clearance for the tape defined by
l = 13,15 mm ± 0,10 mm
The top front of the lid shall have a radius r . The centre of the radius shall be axis A.
+ 0,0 mm
r = 14,7 mm
- 0,3 mm
The design of the locking mechanism is not specified by this International Standard except that is shall be operated by a release
pin in the drive. The lid release mechanism shall be actuated when the drive release pin is in the shaded area (see figure 15)
defined by
l = 2,0 mm ± 0,1 mm
l = 8,2 mm ± 0,2 mm
l = 0,7 mm ± 0,2 mm
o o
a = 30 ± 1
The force required to unlock the lid lock shall not exceed 0,25 N in the direction shown in figure 18.
The force required to open the lid shall not exceed 1,0 N in the direction shown in figure 19.
8.14 Cartridge reel lock (figure 16)
The reels shall be locked when the cartridge is removed from the tape drive. The design of the locking mechanism is not
specified by this International Standard except that it shall be operated by a release pin in the drive.
The locking mechanism shall be accessed through a rectangular hole in the case (see figure 10) defined by the centreline from
Plane Y
l = 34,5 mm ± 0,1 mm;
the top from Plane X
l = 35,85 mm ± 0,15 mm;
and
l = 4,0 mm ± 0,1 mm
l = 6,5 mm min.
The dimension of the locking mechanism shall be defined by
+ 0,3 mm
l = 3,2 mm
- 0,2 mm
l = 4,0 mm ± 0,1 mm
o o
a = 60,0 ± 1,0
The reels shall be locked when the operating face of the release pin is located l from Plane X.
+ 2,0 mm
l = 39,0 mm
- 0,0 mm

ISO/IEC
The reels shall be unlocked when the operating face of the release pin is located l from Plane X.
+ 0,50 mm
l = 41,75 mm
- 0,00 mm
In this position there shall be a clearance of l between the locking mechanism and the inside of the rear wall of the cartridge.
l = 0,5 mm min.
The pin used to move the locking mechanism shall penetrate the cartridge a distance of
l = 7,8 mm max.
The cavity of the locking mechanism shall be defined by
l = 4,0 mm ± 0,1 mm
r = 0,3 mm max.
The force required to unlock the reel lock in the direction shown in figure 17 shall not exceed 1,0 N.
8.15 Reel access holes (figure 10)
The case shall have two circular reel access holes which shall allow penetration of the drive spindles.
The positions of the access holes shall be defined by
l = 23,00 mm ± 0,05 mm
l = 11,40 mm ± 0,05 mm
l = 46,2 mm ± 0,1 mm
The diameter of the holes shall be
d = 18,80 mm ± 0,05 mm
8.16 Interface between the reels and the drive spindles
The drive spindles (see figures 22 and 23) shall engage the reels in the area defined by
l = 11,75 mm ± 0,15 mm
l = 8,30 mm ± 0,05 mm
l = 0,6 mm ± 0,1 mm
l = 0,3 mm ± 0,1 mm
l = 1,10 mm ± 0,05 mm
l = 0,6 mm max.
l = 5,4 mm ± 0,1 mm
l = 4,4 mm ± 0,1 mm
l = 0,6 mm max.
+ 0,08 mm
d = 10,00 mm
- 0,00 mm
d = 16,0 mm max.
+ 0,0 mm
d = 18,0 mm
- 0,1 mm
+ 0,0 mm
d = 16,0 mm
- 0,1 mm
+ 0,0 mm
d = 45,1 mm
- 0,5 mm
+ 0,0 mm
ISO/IEC ISO/IEC 15757:1998 (E)
d = 45,1 mm
- 0,2 mm
There shall be a chamfer of the reel driving hole defined by
l = 2,4 mm ± 0,1 mm
o o
a = 15 ± 1
There shall be a chamfer at the bottom of the reel on the outside edge defined by
l = 0,2 mm max.
o o
a = 45 ± 1
The position and width of the slots to receive the reel drive spindle shall be defined by
+ 0,2 mm
l = 2,4 mm
- 0,0 mm
o o
a = 60 ± 1
The teeth in the reel driving hole shall have a radius
r = 0,2 mm max.
The depth l of the reel driving hole shall be effective to the diameter d .
108 3
l = 9,4 mm min.
+ 0,08 mm
d = 6,50 mm
- 0,00 mm
When the tape is loaded in the drive, the position of the tape centre relative to Plane Z shall be
l = 7,05 mm ± 0,10 mm
When the tape is loaded in the drive, the position of the reel relative to Plane Z shall be
l = 0,6 mm ± 0,2 mm
The penetration of the reel drive spindle into the reel shall be defined by
l = 7,5 mm max.
l = 8,0 mm max.
l = 1,20 mm ± 0,05 mm
l = 1,40 mm ± 0,05 mm
0 o
a = 60 ± 1
When the cartridge is mounted in the drive and the Support areas are at a distance l from Plane Z, the reel spring force F
shall be 0,6 N ± 0,2 N in the direction shown in figure 23.
8.17 Light path (figures 10, 12, 20 and 21)
A light path shall be provided for sensing the leader and trailer tapes. When the lid is open, an unobstructed light path shall
exist from the d diameter light path hole to the outside of the cartridge via square windows in the light path hole (see cross-
section D-D in figure 12) and the light window in the cartridge lid.
The centre of the light path hole shall be defined by l and
l = 8,35 mm ± 0,10 mm
The diameter of the light path hole shall be
+ 0,3 mm
d = 6,5 mm
- 0,0 mm

ISO/IEC
The light path hole shall have a chamfer defined by
l = 0,5 mm max.
o o
a = 45 ± 1
The position and size of the square window on each side of the light path hole shall be
l
= 6,05 mm ± 0,10 mm
+ 0,4 mm
l = 2,5 mm
- 0,0 mm
The hole shall be deep enough to allow penetration of a light emitter a distance of
l = 12,5 mm min.
The angle of the light path shall be
o o
a = 5,50 ± 0,25
The position and size of the cartridge lid window shall be
l = 3,8 mm ± 0,1 mm
+ 0,4 mm
l = 2,5 mm
- 0,0 mm
l = 6,05 mm ± 0,10 mm
8.18 Position of the tape in the case (figure 21)
The tape shall run between two guide surfaces in a plane parallel to Plane X and l from it.
l = 10,15 mm ± 0,10 mm
The guide surfaces shall have a radius of r and shall be tangential, as shown in figure 21, to lines tangential to the reel hubs
that extend to points outside the case.
r = 3,0 mm ± 0,1 mm
These points shall be defined by
l = 76,28 mm ± 0,30 mm
l = 27,15 mm ± 0,20 mm
l = 31,15 mm ± 0,20 mm
l = 9,67 mm ± 0,10 mm
8.19 Tape path zone
When the cartridge is inserted into the drive, the tape is pulled outside the case by tape guides and is no longer in contact with
the guide surfaces. The tape path zone (see figure 21) of the case is the zone in which the tape shall be able to move freely. This
zone shall be maintained for both sides of the case and shall be defined by l to l and
124 127
l = 23,0 mm ± 0,1 mm
l = 0,3 mm min.
l = 46,2 mm ± 0,2 mm
l = 11,4 mm ± 0,1 mm
The clearance between the tape and the guides shall be defined by
l = 0,3 mm min.
8.20 Tape access cavity (figure 10)
When the cartridge is inserted into the drive, tape guides in the drive pull the tape into the drive tape path. The two radii r are
centred on Datum holes A and B. The shape and dimensions of the access cavity for these tape guides shall be defined by l
and l , and the following
r = 2,3 mm ± 0,1 mm
ISO/IEC ISO/IEC 15757:1998 (E)
The two radii r are centred on the centres of the reel access holes.
r = 24,15 mm ± 0,10 mm
l = 3,85 mm ± 0,10 mm
8.21 Tape access cavity clearance requirements (figure 24)
The case design shall provide clearance for drive tape threading mechanisms and shall be defined by
l = 1,2 mm max.
+ 0,20 mm
l = 1,15 mm
- 0,00 mm
+ 0,0 mm
l = 14,0 mm
- 0,2 mm
l = 66,8 mm min.
l = 10,0 mm min.
l = 14,8 mm ± 0,1 mm
o
a = 49 max.
Figure 1 - Tape cartridge assembly top view, lid opened

ISO/IEC
Figure 2 - Tape cartridge assembly bottom view, lid closed
Figure 3 - Reference Planes X, Y, and Z
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 4 - Front side, lid closed
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ISO/IEC
Figure 9 - Bottom side, Datum and Support areas
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 10 - Bottom side, lid removed
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ISO/IEC
Figure 11 - Details of datum and recognition holes
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 12 - Cross-sections of light path holes, recognition holes and write-inhibit hole

ISO/IEC
Figure 13 - Lid
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 14 - Lid release insertion channel
Figure 15 - Lid release requirement

ISO/IEC
Figure 16 - Reel lock and release
Figure 17 - Direction of force needed to unlock the reel lock
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 18 - Direction of force needed to unlock the lid lock
Figure 19 - Direction of force needed to open the lid
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ISO/IEC
Figure 20 - Light path and light window
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 21 - Internal tape path and light path
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ISO/IEC
Figure 22 - Cartridge reel
ISO/IEC ISO/IEC 15757:1998 (E)
Figure 23 - Interface with drive spindle

ISO/IEC
Figure 24 - Tape access cavity clearance
ISO/IEC ISO/IEC 15757:1998 (E)
Section 3 - Requirements for the Unrecorded Tape
9 Mechanical, physical and dimensional characteristics of the tape
9.1 Materials
The recordable area of the tape shall consist of a base material (oriented polyethylene terephthalate film or equivalent) coated
on one side with a strong yet flexible layer of evaporated metal material (or equivalent). The back surface may be coated.
There shall be a leader tape between the take-up hub and PBOT. There shall be a trailer tape between PEOT and the supply
hub. The leader and trailer tapes shall consist of a translucent length of the same or equivalent base material withou
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