Information technology — Data interchange on 12,7 mm 128-Track magnetic tape cartridges — DLT 3 format

Specifies the physical and magnetic characteristics of a 12,7 mm wide, 128-track magnetic tape cartridge, to enable interchangeability of such cartridges. It also specifies the quality of the recorded signals, a format, called Digital Linear Tape 3 (DLT 3), and a recording method.

Technologies de l'information — Échange de données sur cartouches de bande magnétique de 12,7 mm, 128 pistes — Format DLT 3

General Information

Status
Published
Publication Date
20-Mar-1996
Current Stage
9093 - International Standard confirmed
Start Date
07-Apr-2006
Completion Date
21-Aug-2020
Ref Project

Buy Standard

Standard
ISO/IEC 14833:1996 - Information technology -- Data interchange on 12,7 mm 128-Track magnetic tape cartridges -- DLT 3 format
English language
54 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL
ISO/IEC
STANDARD
First edition
1996-03-I 5
Information technology - Data
interchange on 12,7 mm 128-track
magnetic tape cartridges - DLT 3 format
Technologies de I ‘information
- khange de don&es SW cartouches de
bande magn&ique de 12,7 mm, 728 pistes - Format DLT 3
Reference number
lSO/IEC 14833:1996(E)
---------------------- Page: 1 ----------------------
ISO/IEC 14833:1996 (E)
Page
Contents
Section 1: General
1 Scope
2 Conformance
2.1 Magnetic tape cartridges
2.2 Generating systems
2.3 Receiving systems
3 References
4 Definitions
4.1 Average Signal Amplitude
4.2 azimuth
4.3 back surface
4.4 Beginning-Of-Tape marker (BOT)
4.5 byte
4.6 cartridge
4.7 Cyclic Redundancy Check (CRC) character
4.8 Early Warning (EW)
4.9 Error-Detecting Code (EDC)
4.10 End-Of-Tape marker (EOT)
4.11 Entity
4.12 Error-Correcting Code (ECC)
4.13 flux transition position
4.14 flux transition spacing
4.15 Logical Block
4.16 logical track
4.17 magnetic tape
4.18 Master Standard Reference Tape
4.19 object
4.20 page
4.21 physical block
4.22 physical recording density
0 ISO/IEC 1996

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 microfilm,

without permission in writing from the publisher.
ISO/IEC Copyright Office * Case Postale 56 * CH-1211 Geneve 20 * Switzerland
Printed in Switzerland
---------------------- Page: 2 ----------------------
ISO/IEC 14833:1996 (E)
OISO/IEC
4.23 physical track
4.24 Record
4.25 Reference Edge
Reference Field
4.26
4.27 Secondary Standard Reference Tape
4.28 Standard Reference Amplitu
4.29 Standard Reference Current
4.30 Test Recording Current
4.31 Typical Field
5 Conventions and notations
5.8 Representation of numbers
5.2 Dimensions
5.3 Names
5.4 Acronyms
6 Environment and safety
6.1 Cartridge and tape testing environment
6.2 Cartridge operating environment
6.3 Cartridge storage environment
6.4 Safety
6.4* 1 Safeness
6.4.2 Flammability
6.5 Transportation
Section 2: Requirements for the unrecorded tape
7 Mechanical and electrical requirements
7.1 Material
7.2 Tape length
7.3 Width
7.4 Total thickness
7.5 Thickness of the base material
7.6 Thickness of the magnetic coating
7.7 Thickness of the back coating
7.8 Discontinuity
7.9 Longitudinal curvature
7.9.1 Requirement
7.9.2 Procedure
7.10 Out-of-Plane distortions
7.11 Cupping
7.12 Roughness of the coating surfaces
7.12.1 Roughness of the back coating surface
7.12.2 Roughness of the magnetic coating surface
7.13 Coating adhesion
7.14 Layer-to-layer adhesion
. . .
III
---------------------- Page: 3 ----------------------
OISOHEC
ISO/IEC 14833:1996 (E)
7.14.1 Requirements
7.14.2 Procedure
7.15 Modulus of elasticity
7.151 Requirement
7.15.2 Procedure
7.16 Flexural rigidity
7.16.1 Requirement
7.16.2 Procedure
7.17 Tensile yield force
7.17.1 Procedure
7.18 Electrical resistance
7.18.1 Requirement
7.18.2 Procedure
7.19 Inhibitor tape
7.20 Abrasivity
7.20.1 Requirement
7.20.2 Procedure
7.21 Light transmittance of the tape and the leader
7.22 Coefficient of dynamic friction
7.22.1 Requirements
8 Magnetic recording characteristics
8.1 Typical Field
8.2 Signal amplitude
8.3 Resolution
8.4 Overwrite
8.4.1 Requirement
8.5 Peak shift
8.5.1 Requirement
8.52 Procedure
9 Tape quality
9.1 Missing pulses
9.1.1 Requirement
9.2 Missing pulse zone
9.2.1 Requirement
9.3 Tape durability
Section 3: Mechanical specifications of the tape cartridge
10 General
---------------------- Page: 4 ----------------------
ISO/IEC 14833:1996 (E)
OISO/IEC
ottom side and right side
ack side and left side
10.4 Tape leader
10.7 Tape winding
&Aoment of inertia
10.9 Material
equirements for an interchanged tape
Section 4:
11 Method of recording
11.1 Physical recording density
11.2 Channel bit cell length
11.2.1 Average Channel bit cell length
11.2.2 Long-term average Channel bit cell length
11.2.3 Short-term average Channel bit cell length
11.3 Flux transition spacing
11.4 Read signal amplitude
11.5 Azimuth
11.6 Channel skew
12 Tape format
12.1 Reference Edge
12.2 Direction of recording
12.3 Tape layout
12.4 Calibration and Directory Area
12.4.1 Scratch Area
12.4.2 Guard Area Gl
12.4.3 Calibration Tracks Area
12.4.4 Guard Area G2
Directory Area
12.4.5
12.4.6 Guard Area G3
12.5 Data Area
12.5.1 Physical tracks
12.5.2 Width of the physical tracks
12.5.3 Logical tracks
12.5.4 Locations of the physical tracks
12.5.5 Layout of tracks in the Data Area
13 Data format
13.1 Data Bytes
13.2 Logical Blocks
13.3 Data Blocks
13.4 Types of Logical Blocks
13.5 Entities
---------------------- Page: 5 ----------------------
OISO/IEC
ISO/IEC 14833:1996 (E)
13.6 Logical Block format
13.6.1 Preamble
13.6.2 Sync
13.6.3 Data Field
13.6.4 EDC
13.6.5
Control Field 1 (CFl)
13.6.6 Control Field 2 (CF2)
13.6.7 CRC
13.6.8
Postamble
14 Use of Logical Blocks
14.1 Data Blocks
14.2 Filler Blocks
14.3 End of Track Blocks (EOTR)
14.4 End of Data Blocks (EOD)
14.5 ECC Blocks
15 Format of Entities
16 Error handling
Annexes
A - Measurement of light transmittance
B - Generation of the Data Blocks CRCs
C - ECC generation
D - Generation of page CRCs
E - Format of MAP entries
F - Format of Control Field 1
G - Format of Control Field 2
H - Recommendations for transportation
J - Inhibitor tape
K - Recommendations on tape durability
L - Handling guidelines
---------------------- Page: 6 ----------------------
OISO/IEC
ISO/IEC 14833:1996 (E)
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 technical activity. IS0 and IEC technical committees collaborate in 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 JTCl, 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 10090 was prepared by the European Computer Manufacturers Association (as Standard

ECMA-209) and was adopted under a special “fast-track procedure”,
by Joint Technical Committee ISO/IEC JTCl,

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

Annexes A to G form an integral part of this International Standard. Annexes H to L are for information only.

---------------------- Page: 7 ----------------------
ISO/IEC 14833:1996 (E) OISOHEC
Introduction

International Standard ISO/IEC 13421 concerns a magnetic tape cartridge of a type different from that of International

Standards IS0 9661 and ISO/IEC 11559. Whilst the magnetic tape is also 12,7 mm wide, it is characterized by the fact that

the physical tracks, recorded and read in pairs, constitute two groups, the first recorded and read in forward direction, the

second in reverse direction. International Standard ISO/IEC 13962 constitutes a development of the cartridge specified in

International Standard ISO/IEC 13421 in that the number of tracks has been raised from 48 to 112, thus raising the total

capacity of the cartridge accordingly.

This International Standard specifies a further development of the DLT-formatted cartridges. By raising the number of tracks

to 128 and adopting an enhanced format, a further capacity increase is achieved.
---------------------- Page: 8 ----------------------
INTERNATIONAL STANDARD OISO/IEC ISO/IEC 14833:1996 (E)
Information technology - Data interchange on 12,7 mm 1284rack magnetic tape
cartridges - DLT 3 format
Section 1: General
Scope

This International Standard specifies the physical and magnetic characteristics of a 12,7 mm wide, 128-track magnetic tape

cartridge, to enable interchangeability of such cartridges. It also specifies the quality of the recorded signals, a format -

called Digital Linear Tape 3 (DLT 3) - and a recording method. Together with a labelling standard, for instance International

- File structure and labelling of magnetic tapes for information
Standard IS0 1001: 1986, Information processing

interchange, it allows full data interchange by means of such magnetic tape cartridges.

2 Conformance
21 . 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.

22 . Generating systems

A system 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 according to 2.1 meet the mandatory requirements of this International

Standard.
. Receiving systems

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

Standard if it is able to handle any recording made on a tape according to 2.1.
3 Normative reference

The following standard contains provisions which, through reference in this text, constitute provisions of this International

Standard. At the time of publication, the edition indicated was 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

edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International

Standards.
IS0 1302: 1992, Technical drawings - Method of indicating su$ace texture.
4 Definitions

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

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

physical recording density of 1 640 ftpmm measured over a minimum length of track of 25,4 mm, exclusive of missing

pulses.

42 . azimuth : The angular deviation, in minutes of arc, of the mean flux transition line of the recording made on a

track from the line normal to the Reference Edge.

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

44 0 Beginning-Of-Tape marker (BOT) : A hole punched on the centreline of the tape towards the end nearest to

the leader.
---------------------- Page: 9 ----------------------
ISO/IEC 14833tl996 (E) OISO/IEC
45 a byte : An ordered set of bits acted upon as a unit.
NOTE - In this International Standard, all bytes are &bit bytes.

46 0 cartridge : A case containing a single supply reel of 12,7 mm wide magnetic tape with a leader attached at the

outer end.

47 . Cyclic Redundancy Check (CRC) character : A 64-bit character, generated by a mathematical

computation, used for error detection.

48 . Early Warning (EW) : A signal generated by the drive indicating the approaching end of the recording area.

49 a Error-Detecting Code (EDC) t A mathematical computation yielding check bytes used for error detection.

4.10 End-Of-Tape marker (EOT) : A hole punched on the centreline of the tape towards the end farthest from the

leader.

4.11 Entity : A group of ten Logical Blocks treated as a logical unit and recorded on a logical track.

4.12 Error-Correcting Code (ECC) : A mathematical computation yielding check bytes used for the correction of

errors detected by the CRC and the EDC.

flux transition position : The point which exhibits the maximum free-space flux density normal to the tape

4.13
surface.

4.14 flux transition spacing : The distance on the magnetic tape between successive flux transitions.

4.15 Logical Block : The two physical blocks simultaneously written on, or read from, the two physical tracks of a

logical track.

4.16 logical track : A pair of physical tracks that are written or read simultaneously.

4.17 magnetic tape : A tape that accepts and retains magnetic signals intended for input, output, and storage

purposes on computers and associated equipment.

Master Standard Reference Tape : A tape selected as the standard for reference field, signal amplitude,

4.18
resolution, peakshift, and overwrite characteristics.

NOTE - The Master Standard Reference Tape is maintained by the Quantum Corporation.

object : A Record or a Tape Mark Block.
4.19
4.20 page : A logical division of a physical block.

4.21 physical block : A set of contiguous bytes recorded on a physical track and considered as a unit.

number of recorded flux transitions per unit length of track, expressed
4.22 physical recording density : The
flux transitions per millimetre (ftpmm).

4.23 physical track : A longitudinal area on the tape along which a series of magnetic signals can be recorded.

Record : A collection of User Bytes, the number of which is determined by the host.

4.24

4.25 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.
4.26 Reference Field : The Typical Field of the Master Standard Reference Tape.

4.27 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/DLTl” until the year 2003 from Quantum Corporation, 333 South

Street, Shrewsbury, Mass. 015454195, USA.

It is intended that these be used for calibrating tertiary reference tapes for routine calibration.

4.28 Standard Reference Amplitude (SRA) : The Average Signal Amplitude from the Master Standard

Reference Tape when it is recorded with the Test Recording Current at 1 640 ftpmm.

4.29 Standard Reference Current : The current that produces the Reference Field.
4.30

Test Recording Current : The current that is 1,l times the Standard Reference Current.

---------------------- Page: 10 ----------------------
OISO/IEC ISO/IEC 14833: 1996 (E)

4.31 Typical Field t In the plot of the Average Signal Amplitude against the recording field at the physical recording

density of 1 640 ftpmm, the minimum field that causes an Average Signal Amplitude equal to 95 % of the maximum

Average Signal Amplitude.
5 Conventions and notations
Representation of numbers
51 l

The following conventions and notations apply in this International Standard, unless otherwise stated.

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.
are by strings of

- Numbers in binary notation and bit patterns represented ZEROS and ONES shown with the most

significant bit to the left.
52 . Dimensions

Unless otherwise stated, all dimensions in the format figures are in millimetres with a tolerance of k 50 mm.

53 . Names

The names of basic elements, e.g. specific fields, are written with a capital initial letter.

Acronyms
54 .
BOT Beginning of Tape.
cm Control Field 1
CF2 Control Field 2
CRC Cyclic Redundancy Check (character)
ECC Error-Correcting Code
EDC Error-Detecting Code
End of Data
EOD
End of Tape
EOT
End of Track
EOTR
Early Warning
FCTI Forward Calibration Track 1
FCT2 Forward Calibration Track 2
RCTI Reverse Calibration Track 1
RCT2 Reverse Calibration Track 2
2.7 RLL Run Length Limited (method)
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.
Cartridge and tape testing environment
61 .
of this

Unless otherwise stated, tests and measurements made on the cartridge and tape to check the requirements

International Standard shall be carried out under the following conditions:
23 OC I& 2 OC
- temperature:
40 % to 60 %
- relative humidity:
24 h
conditioning before testing:
---------------------- Page: 11 ----------------------
OISO/IEC
ISO/IEC 14833:1996 (E)
62 0 Cartridge operating environment

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

10 “C to 40 “C
- temperature:
20 % to 80 %
relative humidity:
wet bulb temperature: 25 OC max.
NOTE - Localized 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 2 h. There shall be no deposit of moisture on or in the cartridge.

Cartridge storage environment
63 l
Cartridges shall be stored under the following conditions:
- temperature: 16 OC to 32 “C
20 % to 80 %
relative humidity:
wet bulb temperature: 26 OC max.

Tapes intended for archiving data for one year or more shall be stored under the following conditions:

- temperature: 18”Cto26”C
relative humidity: 20 % to 60 %

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.
64 a Safety
6.4.1 Safeness

The cartridge and its components shall not constitute any safety or health hazard when used in the intended manner, or

through any foreseeable misuse in an information processing system.
6.4.2 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.
65 l Transportation

This International Standard does not specify parameters for the environment in which cartridges should be transported.

Annex F gives some recommendations for transportation.
Section 2: Requirements for the unrecorded tape
7 Mechanical and electrical requirements
71 . 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 other surface of the cartridge

shall be coated with a non-ferromagnetic conductive coating.
72 l Tape length

The length of the tape, measured from BOT to EOT, shall be 355 m minimum and 365 m maximum.

73 0 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.

---------------------- Page: 12 ----------------------
OISO/IEC ISO/IEC 14833:1996 (E)
74 . Total thickness

The total thickness of the tape at any point shall be between 12,0 pm and 14,0 pm.

75 . Thickness of the base material
The thickness of the base material shall be between 9,0 pm and 11,O pm.
76 . Thickness of the magnetic coating
The thickness of the magnetic coating shall be between 2,0 pm and 3,0 pm.
77 Thickness of the back coating
The thickness of the back coating shall be between 0,4 pm and 0,9 pm.
78 . Discontinuity

There shall be no discontinuities in the tape between the BOT and EOT such as those produced by tape splicing or

perforations.
79 0 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.
7.9.1 Requirement

Any deviation of the Reference Edge from a straight line shall be continuous and shall not exceed 0,038 mm within any 229

mm length of tape.
7.9.2 Procedure

Measure at a tension of 1,39 N * 0,28 N in a test fixture equipped with two guides spaced at 229 mm. The two guides shall

be spring-loaded to position the Reference Edge of the tape against two edge control surfaces. Measure the maximum

deviation of the Reference Edge of the tape from the line drawn between the two control surfaces.

7.10 But-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.

7.11 Cupping

The departure across the width of the tape from a flat surface shall not exceed 0,76 mm.

Cut a 1,O m t, 0,l m length of tape. Condition it for a minimum of 3 hours in the test environment by hanging it so that both

surfaces are freely exposed to the test environment. 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 which is at least 25 mm high with an inside

diameter of 13,0 mm k 0,2 mm. 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.
7.12 Roughness of the coating surfaces
7.12.1 Roughness of the back coating surface

The back coating surface shall have an arithmetic average roughness Ra between 0,005 pm and 0,025 pm (IS0 1302:N 2).

This measurement shall be made using a contacting stylus of radius 12,5 pm with a 20 mg load, and a 254 p cut-off range.

7.12.2 Roughness of the magnetic coating surface

The magnetic coating surface shall have an arithmetic average roughness Ra between 0,005 0 pm and 0,012 5 pm (IS0

1302: N 3). For this measurement, the contacting stylus radius shall be 12,5 pm with a 20 mg load, and a 254 pm cut-off

range.
7.13 Coating adhesion

The force required to peel any part of the coating from the tape base material shall not be less than 0,2 N.

---------------------- Page: 13 ----------------------
ISO/IEC 14833:1996 (E) OISO/IEC
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”, 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 0,2 N, the test has

failed. If the test piece peels away from the double-sided pressure sensitive tape before the force exceeds 0,2 N, an

alternative type of double-sided pressure sensitive tape shall be used.
v. Repeat i) to iv) for the back coating.
93-0120-A
Figure 1 - Measurement of the coating adhesion
Layer-to-layer adhesion
7.14

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.
7.14.1 Requirements
There shall be no evidence of delamination or other damage to the coatings.
Procedure
7.14.2

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
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:

---------------------- Page: 14 ----------------------
OISO/IEC
ISO/IEC 14833:1996 (E)
Time Temperature
16 h to 18 h
54°C 85 %
54°C 10 % or less
1 hto2h 21 OC 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.

94-0005-A
1ooog
Figure 2 - Measurement of layer-to-layer adhesion
7.15 Modulus of elasticity

The modulus of elasticity (Young’s modulus) is the ratio of stress to strain in the longitudinal direction.

7.15.1 Requirement
The modulus of elasticity shall be between 5 500 N/mm2 and 8 500 N/mm2.
7.15.2 Procedure

Clamp a test piece of tape at least 178 mm in length with an initial 102 mm separation between the jaws of a universal

testing machine with a nominal crosshead speed of 3 mm per minute. Calculate the modulus using the chord of the curve

between the force at 0 % and 1 % elongation.
Flexural rigidity
7.16

Flexural rigidity is the ability of the tape to resist bending in the longitudinal direction.

7.16.1 Requirement

The flexural rigidity of the tape in the longitudinal direction shall be between 0,5 x 10m3 N l mm and 2,9 x 10e3 N . mm.

7.16.2 Procedure
Calculate the flexural rigidity D from the following equation:
---------------------- Page: 15 ----------------------
ISO/IEC 14833:1996 (E)
OISO/IEC
D Ext3
(1 v )
E = modulus of elasticity obtained from 7.15
t = measured thickness of the tape in mm
V = Poisson’s ratio, set to 0,33
7.17 Tensile yield force

The tensile yield force required to elongate the test piece by 3 % shall not be less than 14,7 N.

Procedure
7.17.1

Use a static-weighing-constant-rate-of-grip separation tester capable of indicating the load with an accuracy of 2 %. Clamp a

test piece of tape at least 178 mm long with an initial 102 mm separation between the jaws. Elongate the test piece at a rate

of 51 mm per minute until a minimum elongation of 10 % is reached. The force required to produce an elongation of 3 % is

the tensile yield force.
Electrical resistance
7.18
7.18.1 Requirement
The electrical resistance of any square area of the magnetic coating shall
- be greater than 50 x lo6 Sz
not exceed 50 x 1012 Q
The electrical resistance of any square area of the back coating shall
not exceed 100 x 1 O6 a
7.18.2 Procedure

Condition a test piece of tape in the test environment for 24 h. Position the test piece over two 24-carat gold-plated, semi-

circular electrodes having a radius r - - 254 mm and a finish of at least N4, so that the recording surface is in contact with

each electrode. These electrodes shall be placed parallel to the ground and parallel to each other at a distance d = 12,7 mm

between their centres. Apply a force F of 1,62 N to each end of the test piece. Apply a d.c. voltage of 100 V t 10 V across

the electrodes and measure the resulting current flow. From this value, determine the electrical resistance.

piece and average the 5 resistance

Repeat for a to tal of 5 positions al ong the test readings. For the back coating repeat the

procedure wi th the bat k surface i .n contact with the electrodes.
93-0122-A
Figure 3 - Measurement of electrical resistance
---------------------- Page: 16 ----------------------
ISO/IEC 14833tl996 (E)
OISO/IEC

When mounting the test piece, make sure that no conducting paths exist between the electrodes except that through the

coating under test.
NOTE - Particular attention should be given to keeping the surfaces clean.
Inhibitor tape
7.19

This International Standard does not specify parameters for assessing whether or not a tape is an inhibitor tape. However,

annex J gives further information on inhibitor tapes.
7.20 Abrasivity

Tape abrasivity is the tendency of the magnetic coating to wear the magnetic heads.

7.20.1 Requirement
The depth of the wear pattern in a ferrite wear bar shall be less than 1,27 pm.
7.20.2 Procedure

A test piece 61 m in length shall be passed for 100 passes (50 cycles) over a rectangular bar of manganese zinc ferrite. The

bar shall be 0,3 mm wide and its top surface shall be rounded off with a radius r, = 5

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.