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 22051:2002(E)
©
ISO/IEC 2002

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ISO/IEC 22051:2002(E)
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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 22051:2002(E)
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
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ISO/IEC 22051:2002(E)
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
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ISO/IEC 22051:2002(E)
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
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ISO/IEC 22051:2002(E)
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


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ISO/IEC 22051:2002(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.
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.

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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.
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ISO/IEC 22051:2002(E)
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.
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ISO/IEC 22051:2002(E)
4.22 Record
User data processed as described in Clause 12.
4.23 Reference Edge
The bottom edge of the tape when viewing the magnetic coating of the tape with the BOT to the left and the EOT to the right
of the observer.
4.24 Reference Field
The Typical Field of the Master Standard Reference Tape.
4.25 Secondary Standard Reference Tape
A tape the characteristics of which are known and stated in relation to those of the Master Standard Reference Tape.
NOTE - Secondary Standard Reference Tapes can be ordered under Reference "SSRT/SDLT1" from Quantum Corporation, 333 South
Street, Shrewsbury, Mass. 01545-4195, USA. It is intended that these be used for calibrating tertiary reference tapes for routine calibration.
In principle, these Secondary Standard Reference Tapes will be available for a period of 10 years from the publication of the first version of
this International Standard. However, by agreement between ECMA and Quantum Corporation, this period may be changed to take into
account the demand for such Secondary Standard Reference Tapes.
4.26 Standard Reference Amplitude (SRA)
The Average Signal Amplitude from the Master Standard Reference Tape when it is recorded with the Test Recording Current
at 2 700 ftpmm.
4.27 Standard Reference Current
The current that produces the Reference Field.
4.28 Test Recording Current
The current that is 1,1 times the Standard Reference Current.
4.29 Typical Field
In the plot of the Average Signal Amplitude against the recording field at 2 700 ftpmm, the minimum field that causes an
Average Signal Amplitude equal to 95 % of the maximum Average Signal Amplitude.
5 Conventions and notations
5.1 Representation of numbers
The following conventions and notations apply in this International Standard, unless otherwise stated.
− A measured value is rounded off to the least significant digit of the corresponding specified value. It implies that a
specified value of 1,26 with a positive tolerance +0,01, and a negative tolerance -0,02 allows a range of measured values
from 1,235 to 1,275.
− In each block and in each field the bytes shall be arranged with Byte 1, the least significant, first. Within each byte the bits
shall be arranged with Bit 1, the least significant, first and Bit 8, the most significant bit, last. This order applies to the
data, and to the input and output of the error-detecting and error-correcting codes, and to the cyclic redundancy characters.
− Letters and digits in parentheses represent numbers in hexadecimal notation.
− The setting of bits is denoted by ZERO or ONE.
− Numbers in binary notation and bit patterns are represented by strings of digits 0 and 1 shown with the most significant bit
to the left.
5.2 Dimensions
The dimensions in figures 1 to 3 are nominal dimensions. Unless otherwise stated, all dimensions in the other figures are in
millimetres with a tolerance of ± 50 mm.
5.3 Names
The names of basic elements, e.g. specific fields, are written with a capital initial letter.
5.4 Acronyms
BOT Beginning of Tape
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ISO/IEC 22051:2002(E)
CAF Coarse Alignment Field
CF1 Control Field 1
CF2 Control Field 2
CRC Cyclic Redundancy Check (character)
CT1 Calibration Track 1
CT2 Calibration Track 2
FAF1 Fine Alignment Field 1
FAF2 Fine Alignment Field 2
ECC Error-Correcting Code
EDC Error-Detecting Code
EOD End of Data
EOT End of Tape
EOTR End of Track
SRA Standard Reference Amplitude
6 Environment and safety
Unless otherwise stated, the conditions specified below refer to the ambient conditions in the test or computer room and not to
those within the tape drive.
6.1 Cartridge and tape testing environment
Unless otherwise stated, tests and measurements made on the cartridge and tape 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 before testing: 24 h min.
6.2 Cartridge operating environment
Cartridges used for data interchange shall be capable of operating under the following conditions:
− temperature:  10 °C to 40 °C
− relative humidity: 20 % to 80 %
− wet bulb temperature: 26 °C max.
NOTE - Localised tape temperatures in excess of 49 °C may cause tape damage.
If during storage and/or transportation a cartridge has been exposed to conditions outside the above values, it shall be
conditioned before use by exposure to the operating environment for a time equal to, or greater than, the time away from the
operating environment up to a maximum of 24 h. There shall be no deposit of moisture on or in the cartridge.
6.3 Cartridge storage environment
Cartridges shall be stored under the following conditions:
− temperature:  16 °C to 32 °C
− relative humidity:  20 % to 80 %
− wet bulb temperature: 26 °C max.
The stray magnetic field at any point on the tape shall not exceed 4000 A/m. There shall be no deposit of moisture on or in the
cartridge.
6.4 Safety
The cartridge and its components shall satisfy the requirements of IEC 60950 when used in the intended manner or in any
foreseeable use in an information processing system.
6.5 Flammability
The cartridge and its components shall be made from materials which, if ignited from a match flame and when so ignited, do
not continue to burn in a still carbon dioxide atmosphere.
6.6 Transportation
This International Standard does not specify parameters for the environment in which cartridges should be transported. Annex
G gives some recommendations for transportation.
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ISO/IEC 22051:2002(E)
Section 2 - Requirements for the unrecorded tape
The measurements specified in Section 2 shall be performed on an unrecorded tape with servo marks
(See 7.20) on the back surface.
7 Mechanical and electrical requirements
7.1 Material
The tape shall consist of a base material (oriented polyethylene terephthalate film or its equivalent) coated on one surface with
a strong yet flexible layer of ferromagnetic material dispersed in a suitable binder. The back surface of the tape shall be coated
with a non-ferromagnetic conductive coating.
7.2 Tape length
The length of the tape from the leader splice to the hub shall be 558 m ± 1 m.
7.3 Tape width
The width of the tape shall be 12,649 mm ± 0,010 mm.
The width shall be measured across the tape from edge to edge when the tape is under a tension of less than 0,28 N.
7.4 Tape thickness
The total thickness of the magnetic tape at any point shall be between 8,20 µm and 9,30 µm.
7.5 Discontinuity
There shall be no discontinuities in the tape between the BOT and EOT such as those produced by tape splicing or
perforations.
7.6 Longitudinal curvature
The longitudinal curvature is measured as the departure of the Reference Edge of the tape from a straight line along the
longitudinal dimension of the tape in the plane of the tape surface.
7.6.1 Requirements
Any deviation of the Reference Edge from a straight line shall be continuous and shall not exceed 0,076 mm within any 229
mm length of tape.
7.6.2 Procedure
i. Measure at a tension of 1,39 N ± 0,28 N in a test fixture equipped with two guides spaced at 229 mm.
ii. Spring-load the two guides to position the Reference Edge of the tape against two edge control surfaces.
iii. Measure the maximum deviation of the Reference Edge of the tape from the line drawn between the two control surfaces.
7.7 Out-of-Plane distortions
All visual evidence of out-of-plane distortion shall be removed when the tape is subjected to a uniform tension of 0,6 N. Out-
of-plane distortions are local deformations which cause portions of the tape to deviate from the plane of the surface of the tape.
Out-of-plane distortions are most readily observed when the tape is lying on a flat surface under no tension.
7.8 Cupping
The departure across the width of the tape from a flat surface shall not exceed 2,54 mm.
Procedure
i. Cut a 1,0 m ± 0,1 m length of tape. Condition it for a minimum of 3 h in the test environment by hanging it so that both
surfaces are freely exposed to the test environment.
ii. From the centre portion of the conditioned tape cut a test piece of approximately 25 mm length. Stand the test piece on its
end in a cylinder that is at least 25 mm high with an inside diameter of 13,0 mm ± 0,2 mm.
iii. With the cylinder standing on an optical comparator measure the cupping by aligning the edges of the test piece to the
reticle and determining the distance from the aligned edges to the corresponding surface of the test piece at its centre.
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ISO/IEC 22051:2002(E)
7.9 Roughness of the coating surfaces
7.9.1 Roughness of the back coating surface
The back coating surface shall have an arithmetic average roughness R between 0,003 µm and 0,027 µm (ISO 1302:N 2).
ab
This measurement shall be made using a contacting stylus of radius 12,5 µm with a 20 mg load, and a 254 µm cut-off range.
7.9.2 Roughness of the magnetic coating surface
The magnetic coating surface shall have an arithmetic average roughness R between 0,003 µm and 0,008 µm (ISO 1302:
am
N 3). The set up for this measurement shall be identical with that of 7.9.1.
7.10 Coating adhesion
The force required to peel any part of the coating from the tape base material shall not be less than 0,016 N.
Procedure
i. Take a test piece of the tape approximately 380 mm long and scribe a line through the recording coating across the width
of the tape 125 mm from one end.
ii. Using a double-sided pressure sensitive tape, attach the full width of the test piece to a smooth metal plate, with the
magnetic coating (recording surface) facing the plate, as shown in figure 1.
iii. Fold the test piece over 180°, adjacent to, and parallel with, the scribed line. Attach the metal plate and the free end of the
test piece to the jaws of a universal testing machine and set the speed of the jaw separation to 254 mm per min.
iv. Note the force at which any part of the coating first separates from the base material. If this is less than 0,016 N, the tape
has failed the test. If the test piece peels away from the double-sided pressure sensitive tape before the force 0,010 N, an
alternative type of double-sided pressure sensitive tape shall be used.
v. Repeat i) to iv) for the back coating.

Recording surface Scribed line
125 mm Pressure-sensitive tape
93-0120-A


Figure 1 - Measurement of coating adhesion
7.11 Layer-to-layer adhesion
Layer-to-layer adhesion refers to the tendency of a layer, when held in close proximity to the adjacent layer, to bond itself to an
adjacent layer so that free and smooth separation of the layers is difficult.
7.11.1 Requirements
There shall be no evidence of delamination or other damage to the coatings.
7.11.2 Procedure
i. Fasten one end of a 914 mm length of tape, magnetic coating inwards, to a horizontally mounted stainless steel cylinder
with a low cold-flow adhesive material.
ii. The dimensions of the cylinder shall be:
- diameter: 12,7 mm
- length: 102 mm
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ISO/IEC 22051:2002(E)
iii. Attach a mass of 1 000 g to the opposite end of the tape.
iv. Attach, 25,4 mm above the mass, a narrow strip of double-sided adhesive tape to the magnetic coating.
v. Slowly rotate the cylinder, so that the tape winds uniformly around it into a compact and even roll. The double-sided tape
secures the end and prevents unwinding when the mass is removed.
vi. The cylinder with the tape shall then be exposed to the following temperature and humidity cycle:
Time Temperature RH
16 h to 18 h 54 °C 85 %
4 h 54 °C 10 % or less
1 h to 2 h 21 °C 45 %

vii. Open the end of the roll and remove the double-sided adhesive tape.
viii. Release the free end of the tape.
ix. The outer one or two wraps shall spring loose without adhesion.
x. Hold the free end of the tape and allow the cylinder to fall, thereby unwinding the tape.
xi. The tape shall show no coating delamination, except for the 51 mm of tape nearest to the cylinder.
12,712,7
914914
25,425,4
stripstrip
10001000 gg
94-0085-A94-0085-A

Figure 2 - Measurement of layer-to-layer adhesion
7.12 Modulus of elasticity
The modulus of elasticity (Young's modulus) is the ratio of stress to strain in the longitudinal direction.
7.12.1 Requirement
2 2
The modulus of elasticity shall be between 5 884 N/mm and 11 768 N/mm .
7.12.2 Procedure
i. Clamp a test piece of tape at least 180 mm in length with an initial 100 mm separation between the jaws of a universal
testing machine with a nominal crosshead speed of 3 mm per minute.
ii. Calculate the modulus using the chord of the curve between the force at 0 % and 1 % elongation.
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ISO/IEC 22051:2002(E)
7.13 Flexural rigidity
Flexural rigidity is the ability of the tape to resist bending in the longitudinal direction.
7.13.1 Requirement
-7 . -7 .
The flexural rigidity of the tape in the longitudinal direction shall be between 3 x 10 N mm and 9 x 10 N mm.
7.13.2 Procedure
Calculate the flexural rigidity D from the following equation:
3
Et
2
 D = ()1 − υ
12
where:
E = modulus of elasticity obtained from 7.12
t = measured thickness of the tape in mm
ν = Poisson's ratio, set to 0,33
7.14 Tensile yield force
The tensile yield force required to elongate the test piece by 3 % shall not be less than 9,6 N.
7.14.1 Procedure
i. Use a static-weighing-constant-rate-of-grip separation tester capable of indicating the load with an accuracy of 2 %.
ii. Clamp a test piece of tape at least 178 mm long with an initial 102 mm separation between the jaws.
iii. Elongate the test piece at a rate of 51 mm per minute until a minimum elongation of 10 % is reached.
iv. The force required to produce an elongation of 3 % is the tensile yield force.
7.15 Electrical resistance
7.15.1 Requirement
The electrical resistance of any square area of the magnetic coating shall
6
− be greater than 10 Ω
12
− not exceed 50 x 10 Ω
The electrical resistance of any square area of the back coating shall
6
− not exceed 100 x 10 Ω
7.15.2 Procedure
i. Condition a test piece of tape in the test environment for 24 h.
ii. Position the test piece over two 24-carat gold-plated, semi-circular electrodes having a radius r = 25,4 mm and a finish of
at least N4, so that the recording surface is in contact with each electrode.
iii. Place these electrodes parallel to the ground and to each other at a
...