1、INTERNATIONAL STANDARD ISO/IEC 8441-l First edition 1991-05-15 Information technology - High density digital recording (HDDR) - Part 1: Unrecorded magnetic tape for (HDDR) applications Technologies de /information - Enregisfremenf numkrique 9 haufe densif (HDDR) - Parfie I: Bande magnbfique vierge p
2、our les applications HDDR Reference number ISO/IEC 8441-1:1991(E) ISOllEC 8441-1:1991(E) Contents Page 1 Scope . 1 2 Normative references . 1 3 Definitions 1 4 General 3 4.1 Materials . 3 4.2 Tape reels . 3 4.3 Tape wind 3 4.4 Packaging 3 5 Test conditions 3 5.1 General 3 5.2 Conditioning 3 5.3 Test
3、 environment 3 6 Dimensions . 3 6.1 Tape width . 3 6.2 Tape length . 4 6.3 Tape thickness . 4 7 Physical properties . 4 7.1 Yield strength 4 7.2 Elongation under stress 4 8 Performance 5 8.1 Reference test system . 5 8.2 Sensitivity 5 8.3 Wavelength response 5 8.4 Output level uniformity (long term)
4、 6 8.5 Instantaneous nonuniformity (dropouts) 6 0 ISOllEC 1991 All rights reserved. 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. ISOllEC Copyrig
5、ht Office l Case Postale 56 l CH-1211 Genkve 20 l Switzerland Printed in Switzerland ii ISOllEC 8441-1:1991(E) 8.6 Signal-to-noise ratio . . . . _._._._._._. 6 8.7 Ease of erasure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、. . . . . . . . . . . . . . . . 7 8.8 Electrical surface resistance . . . _._,_ 7 8.9 Environmental performance 9 8.10 Durability . 9 8.11 Abrasivity 9 Annexes A Glass- and metal-flanged tape reels 10 B Wear of recording heads . 11 C Environmental conditions . . . _._I._. 12 C.l General ,._._._._,._
7、._._,_,.,_.,.,.,_,.,.,. 12 C.2 Normal operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 C.3 Extended operating conditions . 12 C-4 Severe operating conditions3) 12 C.5 Shipping and short-term storage ,.,.,.,. 12 C.6 Extended shipping and short-term storage 12 C.7 Re
8、commended long-term storage 12 C.8 Deterioration of tape arising from exposure to adverse environmental conditions _,.,.,.,._.,._._. 12 D Severe operating conditions . 14 D.l Application . 14 D.2 Conditions .,_._._._ 14 D.3 Environmental performance tests for limited duration recording under severe
9、conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D.3.1 Definition of severe conditions 14 D.3.2 Requirement 14 D.3.3 Test procedure 14 E Surface electrical resistance testing 16 E.l Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10、 . . . . . 16 E-2 Test specimens 16 E.3 Apparatus . 16 E.3.1 Electrodes for testing insulation resistance _. 16 . . . III ISOllEC 8441-1:1991(E) E.3.2 Electrodes for testing volume and surface resistance 16 E.3.3 Electrode materials . 16 E.3.4 Direct-current potential . 16 E.3.5 Measuring equipment
11、. 17 E.3.6 Switches and keys . 17 E.4 Procedure . 17 E.4.1 Conditioning of specimens . 17 E.4.2 Precautions in mounting specimens . 17 E.4.3 Method of measuring resistance . 17 E.4.4 Insulation resistance determination 19 E.4.5 Volume and surface resistance determination 19 E.4.6 Surface resistance
12、determination 20 E.5 Report . 21 F Tape abrasivity testing . 26 F.l Scope 26 F.2 Principle 26 F.3 Apparatus . 26 F.3.1 Sensor 26 F.3.2 Dummy head assembly 26 F.3.3 Tape abrasivity meters) . 26 F.3.4 Reference tape5) 26 F.4 Procedure . 26 F.4.1 Cleaning and measuring 26 F.4.2 Requirement 27 G Bibliog
13、raphy . 28 iv ISOllEC 8441-1:1991(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 I
14、nternational Standards through technical committees established by the respective organization to deal with particular fields of technical activity. IS0 and IEC technical com- mittees collaborate in fields of mutual interest. Other international or- ganizations, governmental and non-governmental, in
15、 liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bod- ies for voting. Publication a
16、s an International Standard requires ap- proval by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 8441-1 was prepared by Joint Technical Committee ISO/IEC JTC 1, information technology. ISO/IEC 8441 consists of the following parts, under the general title In- for
17、mation technology - High density digital recording (HDDR): - Part I: Unrecorded magnetic tape for (HDDR) applications - Part 2: Guide for interchange practice Annexes A, 6, C, D, E, F and G of this part of ISO/IEC 8441 are for infor- mation only. V ISOllEC 8441-1:1991(E) Introduction This part of IS
18、O/IEC 8441 gives guidance on the performance levels of unrecorded tape suitable for high density digital recording for inter- change purposes. It should be noted that the performance levels speci- tied may differ from those attained at the time of purchase of the tape. vi INTERNATIONAL STANDARD ISOl
19、lEC 8441-1:1991(E) Information technology - High density digital recording (HDDR) - Part 1: Unrecorded magnetic tape for (HDDR) applications 1 Scope This part of ISO/IEC 8441 specifies requirements for unrecorded magnetic tape designed for high density digital recording (HDDR) having the following c
20、haracteristics: a) nominal thickness 25,4 pm (0,001 in); b) longitudinal magnetic orientation; c) coercivity 72 kA/m (900 Oe) max. These tapes are suitable for interchange in accord- ance with ISO/IEC 8441-2. Requirements for packaging are also included. NOTE 1 Tapes of coercivity above 32 kA/m (400
21、 Oe) are usually classified as high energy tapes and users should establish compatibility with equipment used for driving them. Annex A gives guidance on glass and metal-flanged reels. Annex B gives information on the wear of re- cording heads. Different categories of environmental conditions and th
22、eir effects on tape are dealt with in annex C. Severe operating conditions are con- sidered in annex D. Surface electrical resistance testing is dealt with in annex E. A tape abrasivity testing technique is described in annex F. A list of bibliographical references is given in annex G. NOTES 2 It is
23、 recognized that archival interchange tapes, or those produced by systems in use prior to the publication of this part of ISOllEC 8441, may not comply with the re- quirements and/or recommendations herein. 3 Various tests and procedures herein refer to recording with a.c. HF bias. In practice, certa
24、in HDDR systems do not use bias. The use of bias in this part of ISO/IEC 8441 does not imply that the tape so tested is in any way un- suitable for a biasless system. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of thi
25、s part of ISO/IEC 8441. At the time of publica- tion, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO/IEC 8441 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated b
26、elow. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. IS0 1184:1983, Plastics - Determination of tensile properties of films. IS0 1860:1986, information processing - Precision reels for magnetic tape used in interchange instru- mentation applications. 3 Defini
27、tions For the purpose of this part of ISO/IEC 844 lowing definitions apply. 1, the fol- NOTE 4 Tape speed is taken to be 3048 m/s unless otherwise stated. (120 in/s), 3.1 abrasivity: The propensity of a magnetic tape to cause wear of a recording head, by the passage of the tape over the head. 1 ISOl
28、lEC 8441-1:1991(E) NOTES duration, in microseconds, for a tape speed of 3048 m/s (120 in/s) (for a general definition, see ISOllEC 8441-2). 5 It may be expressed as micrometres of head wear per metre of tape passed (microinches per inch), or as a value relative to a given reference tape. 6 The actua
29、l wear produced in the recording head will also depend on the tape speed and tension (see annex B). 3.2 durability: The ability of a tape to maintain its output uniformity and dropout characteristics after a given number of passes on the reference test re- corder. 3.3 ease of erasure: The ability of
30、 a specified eras- ing field to effect a specified reduction in the level of a signal recorded on a tape. 3.4 electrical surface resistance: The surface re- sistance, in ohms per square, of the magnetic coat- ing or the back surface of a tape, as appropriate. NOTE 7 The SI unit of surface resistivit
31、y is the ohm, al- though ohms per square is used in practice. 3.5 elongation under stress: The increase in the distance between reference lines on the test piece due to a tensile load, expressed as a percentage of the initial distance between the reference lines. 3.6 E value: The radial distance by
32、which the reel flanges extend beyond the outermost layer of tape wound on a reel under a tensile force of 0,109 N/mm + 0,033 N/mm of tape width (10 ozf/in + 3 ozf/in of tape width). NOTE 8 0,109 N/mm f 0,033 N/mm is equivalent to 282 gflin + 85 gflin. 3.7 instantaneous nonuniformities (dropouts): A
33、tape defect which causes a reduction in the repro- duced signal amplitude sufficient to jeopardize or impair data recovery. For the purpose of this part of ISO/IEC 8441, the on- set of a dropout event is denoted by a 12 dB re- duction in the output level from a 0,635 mm (0,025 in) wide track of a 1,
34、524 pm (60 pin) wavelength test signal recorded as a square wave slightly above saturation level (see 8.5.1). The end of a dropout event is denoted by recovery of the signal to within 9 dB of the average level. NOTES 9 The dropout count associated with each dropout event is the duration of the event
35、 expressed as one-half of the number of test signal periods occurring during the dropout event. 10 For a tape speed of 3 048 m/s (120 in/s) the test signal period is 0,5 vs. Hence, the dropout count is equal to the 3.6 operating bias current: That bias current through the recording head which gives
36、a 2 dB fall- off (overbias peak) of the peak output from the ref- erence tape when a 2,0 MHz signal is recorded at reference level (see 3.13), at a tape speed of 3048 m/s (120 in/s). 3.9 output level uniformity (long term): The differ- ence between the maximum and minimum peak output levels, the pea
37、k value in either case being the value that contains 95 % of the peaks (see figure 1 and 8.4). r 95 % probability band /- Envelope of peak amplitudes Replayed frequency 1 MHz F Tape speed 1,524 m/s (60 in/s) Baseline Short-term uniformity (see 8.5): 10 s Long-term uniformity (see 8.6): entire tape M
38、easurement time, f Deviation from uniformity = 20 loglo - dB Figure 1 - Replayed waveform for output uniformity test 3.10 reference tape: An unrecorded length of tape used as a reference. NOTE 11 The reference tape should be one adopted by agreement between the interchange parties. When abso- lute q
39、uantitative performance levels and an international source of standard reference tapes have been estab- lished, such agreements may be replaced by reference to standard reference tapes. 3.11 reference head: A head used in conjunction with the reference tape. NOTE 12 The reference head should be agre
40、ed on be- tween the interchange parties. 2 ISOllEC 8441-1:1991(E) 3.12 reference output level: The reproduce level of a 200 kHz signal recorded on the reference tape at 6 dB below standard record level 3048 m/s (120 in/s) and with operating bias current. 3.13 reference record level 3.13.1 with a.c.
41、bias: The input level of a 200 kHz signal recorded on the reference tape at 3048 m/s (120 in/s), with operating bias current such that on play back, the output signal has 1 % third-harmonic distortion as measured with a wave analyser. 3.13.2 without a.c. bias: The record head reference current level
42、 without a.c. bias (generally expressed in milliamperes peak-to-peak) is established in ac- cordance with ISO/IEC 8441-2. The same current level (in milliamperes) established at the record head to 200 kHz and for tape speed 3084 m/s (120 in/s) is defined as the reference record level. 3.14 secondary
43、 reference tape: An unrecorded length of tape, the magnetic characteristics (i.e. sensitivity, wavelength response, bias character- istic, distortion characteristics), of which have been calibrated against the reference tape. 3.15 sensitivity: The output of the tape sample un- der test compared to t
44、hat from the reference tape expressed as a ratio, normally quoted in decibels, the frequency being 200 kHz in both cases. 3.16 signal-to-noise ratio: The ratio of the repro- duced signal power from a tape and the wideband noise power (tape and equipment) measured over the system bandwidth. 3.17 wave
45、length response: The output voltage fre- quency characteristic of the tape when normalized to a specific wavelength compared to the response of the reference tape. 4 General 4.1 Materials The tape shall consist of a uniform layer of ferromagnetic material held in a flexible binder me- dium on a suit
46、able continuous and splice-free, flex- ible base material with a conductive back coating. 4.2 Tape reels The tape shall be wound on reels in accordance with IS0 1860. NOTE 13 Glass-flanged reels are preferable to reels with metal flanges, with or without window slots (see an- nex A), particularly fo
47、r recorders in performance catego- ries B and C (see IS0 8441-2, annex A) because they are known to give improved performance and greater pro- tection against dropouts, especially if combined with pro- tecting collars. 4.3 Tape wind The tape shall be wound with the magnetic coated surface innermost.
48、 NOTE 14 This is sometimes called “A” wind. 4.4 Packaging Each reel shall be enclosed by an individual wrap- per (e.g. polyethylene) packaged in an appropriate container which provides support of the enclosed reel at the hub. If windowless flanges with wraparound bands are used, the wrapper may not
49、be necessary. 5 Test conditions 5.1 General For all procedures described in this part of ISO/IEC 8441, conditioning shall be as specified in 5.2, and in the test environment as specified in 5.3. 5.2 Conditioning Conditioning shall be carried out in the test en- vironment (see 5.3). The tape may be tissue cleaned. It shall be wound and rewound with a tensile force of 0,109 N/mm + 0,33 N/mm of tape width (10 ozf/in k 3 ozf/in of tape width). The tape shall then be stored,
