1、INTERNATIONAL STANDARD ISOAEC 1864 Fourth edition 1992-06-I 5 Information technology - Unrecorded 12,7 mm (0,5 in) wide magnetic tape for information interchange - 32 ftpmm (800 ftpi), NRZI, 126 ftpmm (3 200 ftpi) phase encoded and 356 ftpmm (9 042 ftpi), NRZI Technologie de /information - Bande mag
2、nktique vierge de 12,7 mm (0,5 in) de large, pour /change dinformation - 32 ftpmm (800 ftpi), NRZI, 126 Rpmm (3 200 ftpi) par codage de phase et 356 ftpmm (9 042 ftpi), NRZI Reference number ISO/IEC 1864:1992(E) ISOllEC 1864:1992(E) Foreword IS0 (the international Organization for Standardization) a
3、nd IEC (the In- ternational 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
4、 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 liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and
5、 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 as an International Standard requires ap- proval by at least 75 % of the national bodies casting a vote
6、. International Standard ISO/IEC 1864 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Sub-Committee SC 11, Flexible magnetic media for digital data interchange. This fourth edition cancels and replaces the third edition (IS0 1864:1985), of which it constitutes a tech
7、nical revision. Annexes A and B form an integral part of this International Standard. Annex C is for information only. 0 ISO/IEC 1992 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 micro
8、film, without permission in writing from the publisher. ISO/IEC Copyright Office l Case POStale 56 l CH-1211 Gen SRA: The Aver- age Signal Amplitude from the Master Standard Reference Tape when it is recorded with the appro- priate Test Recording Current at one of the specified physical recording de
9、nsities. Traceability to the Standard Reference Amplitude is provided by the calibration factor(s) supplied with each Secondary Standard Reference Tape. 3.10 reference edge: The edge furthest from an observer when the tape is lying flat with the mag- netic surface uppermost and the direction of move
10、- ment for recording is from left to right. 3.11 in-contact: An operating condition in which the magnetic surface of a tape is in contact with a mag- netic head. 3.12 track: A longitudinal area on a tape along which a series of magnetic signals may be recorded. 3.13 row: Nine transversely-related lo
11、cations (one in each track) in which bits are recorded. 3.14 position of flux transition: That point which exhibits the maximum free-space flux density normal to the tape surface. 3.15 physical recording density: The number of re- corded flux transitions per unit length of track (ftpmm or ftpi). 3.1
12、6 data density: The number of data characters stored per unit length of tape (cpmm or cpi). 3.17 resistance per square: The surface resistance of a square area of any size measured between electrodes placed along two opposite sides of the square. The unit of measurement is the ohm. 3.18 oxide coatin
13、g to brass and chrome: The re- sistance of the tape oxide coating to motion on brass (chrome). 3.19 oxide coating to tape back surface: The re- sistance of the tape oxide coating to motion on the tape back surface. 3.20 tape back surface to stainless steel: The re- sistance of the tape back surface
14、to motion on stainless steel. 3.21 rubber to tape back surface: The resistance of the tape back surface to motion on rubber. 4 Environment The conditions specified below refer to the ambient conditions in the test or computer room and not to those within the tape drive equipment. 4.1 Testing environ
15、ment Unless otherwise stated, all measurements made on a tape to check compliance with the require- ments of this International Standard and all tests 2 ISOllEC 1864:1992(E) prescribed for a tape in this International Standard shall be carried out under the environmental con- ditions of 23 “C + 2 “C
16、 (73 “F + 4 OF) and relative humidity 40 % to 60 %, after at least 24 h of con- ditioning in the same environment. 4.2 Operating environment The operating temperature shall be within the range 16 “C to 32 “C (60 “F to 90 OF) and the relative hu- midity 20 % to 80 %. Operation near the extremes of th
17、ese ranges can result in degraded performance. The wet bulb temperature shall not exceed 25 “C (78 “F). 4.3 Storage environment During storage, it is recommended that the tapes are kept within the following conditions: 4.3.1 Unrecorded tape temperature: 5 “C to 48 “C (40 “F to 120 OF) relative humid
18、ity: 20 % to 80 % wet bulb temperature: not greater than 26 “C (80 OF) 4.3.2 Recorded tape temperature: 5 “C to 32 “C (40 “F to 90 OF) relative humidity: 20 % to 80 % wet bulb temperature: not greater than 26 “C (80 OF) 5 Characteristics of the tape 5.4 Base material thickness The base material thic
19、kness shall be 0,038 mm (0,001 5 in) nominal. 5.5 Coating thickness The coating thickness shall not exceed 0,015 mm (0,000 6 in). 5.6 Length The normal minimum length of tape is 732 m (2 400 ft) splice-free. If the length of the tape is less than 732 m (2 400 ft), the actual length shall be stated.
20、Maximum tape length is limited by thickness, E value (see 5.7), moment of inertia and reel di- mensions. 5.7 E value The E value is the radial distance by which the reel flanges extend beyond the outermost layer of a tape which has been wound at a tension of 2 N to 3,6 N (7 ozf to 13 ozf) on the spe
21、cified reel. The minimum E value shall be 3,2 mm (0,125 in). When the tape is used with a self-loading cartridge (see IS0 6098), the E value shall satisfy: 6,3 mm (0,25 in) E 15,9 mm (0,625 in) 5.8 Elastoplastic properties The elastoplastic properties of the tape shall be such that when the tape is
22、subjected to a tension of 30 N (108 ozf) for a period of 3 min under any com- bination of temperature and relative humidity within the ranges of 10 “C to 50 “C (50 “F to 122 “F) and 20 % to 80 % relative humidity, the permanent elongation measured with negligible tension after a second 3 min interva
23、l is less than 1.0 %. 5.1 Material 5.9 Longitudinal curvature The tape shall consist of a base material (oriented polyethylene terephthalate film or its equivalent) coated on one side with a strong yet flexible layer of ferromagnetic material dispersed in a suitable binder. If the tape is also coate
24、d on the rear surface, the coating shall be non-ferromagnetic. 5.2 Width The width of the tape shall be 12,7 $;y mm (0,500 T$!j in). 5.3 Total tape thickness The total tape thickness, at any point, shall be 0,048 mm + 0,008 mm (0,001 9 in + 0,000 3 in). There shall be a minimum radius of curvature f
25、or the edge of the tape, defined and tested by allowing a 1 m (36 in) length of the tape to unroll and assume its natural curvature on a flat surface. The minimum radius shall be 33 m (108 ft). If measured over an arc of a circle, this corresponds to a deviation of 3,8 mm (A/8 in) from a 1 m (36 in)
26、 chord. 5.10 Tape wind Tape shall be wound, with its magnetic surface to- ward the reel hub, in a clockwise direction; i.e. when the reel is viewed from the front, the loose end of the tape hangs from the right side of the reel. Tape shall be wound with a tension of 2 N to 3,6 N (7 ozf to 13 ozf) (s
27、ee figure 2). 3 ISOllEC 1864:1992(E) 5.11 Magnetic properties 5.16 Test for missing pulses and extra pulses The magnetic properties of the tape are not defined here by B-H loops or similar parameters, but are defined by the testing procedures given in 5.13 and 5.15. 5.12 Test density For the purpose
28、 of testing tape in accordance with this International Standard, the physical recording density shall be 32 ftpmm, 126 ftpmm or 356 ftpmm (800 ftpi, 3 200 ftpi or 9 042 ftpi). The flux transitions shall be uniformly spaced. The flux transition spac- ing and the track configuration shall conform to I
29、S0 1863, IS0 3788 or IS0 5652 as appropriate. 5.13 Typical Field The Typical Field of the tape under test shall be within + 20 % of the Reference Field for a physical recording density of 32 ftpmm (800 ftpi) or 126 ftpmm (3 200 ftpi) and within at 126 ftpmm (3 200 ftpi), any pair of consecutive outp
30、ut pulses from any track together having a peak-to-peak amplitude less than 35 % of the SRA; at 356 ftpmm (9 042 ftpi), any signal from any track having a base-to-peak amplitude less than 35 % of half the SRA; 5.16.2 Extra pulses Following DC-erasure of the tape on the machine used for conducting th
31、e missing pulse test as de- scribed in 5.16.1, any signal from any track when measured base-to-peak which exceeds 10 % of half the SRA shall be an extra pulse. 5.16.3 Allowable number of missing pulses and extra pulses The allowable number of missing pulses and of ex- tra pulses is not specified by
32、this International Standard, but is a matter for agreement between interchange pat-ties. NOTE 5 It is considered impractical to specify this number for the following reasons: a) the performance of test equipment for magnetic tape is not uniform but depends on such things as tape tension, head design
33、, and the method of guidance employed; b) different machines and systems of programming vary in their ability to tolerate missing and extra pulses on tapes. 4 5.17 Reflective markers ISOllEC 1864:1992(E) 5.20 Resistance Each reel of tape shall be furnished. with two photo- reflective markers, each c
34、onsisting of, or equivalent to, a transparent plastic base with a metallic (for example, vaporized aluminium) coating sandwiched between the base and a thin layer of low cold flow thermal setting adhesive. Reflective markers shall be placed on the side of the tape which does not carry the magnetic s
35、urface, and they shall be on opposite edges of the tape with the beginning-of-tape reflective marker (BOT) on the reference edge. The width of the markers shall be 4,8 mm f 0,5 mm (0,19 in + 0,02 in). The length of the markers shall be 28 mm + 5 mm (I,1 in f 0,2 in). The thickness of the markers, me
36、asured after their application to the tape, shall be not greater than 0,020 mm (0,000 8 in). The beginning-of-tape reflective marker (BOT) shall be placed 4,9 m + 0,6 m (16 fl + 2 ft) from the be- ginning of the tape and the end-of-tape marker (EOT) shall be placed 7,6 I!;$ m (25 1: ft) from the end
37、 of the tape and such th&t the tested area is at least 720,6 m (2 363 fit) in length. The distance from the outer edge of a marker to the adjacent edge of the tape shall be 0,8 mm max. (0,031 in max.) and the marker shall not protrude beyond the edge of the tape. The markers shall be free of wrinkle
38、s and excessive adhesive. NOTE 6 It is desirable that the thinnest markers be employed which perform satisfactorily in minimizing the distortion of the layers of tape adjacent to them. 5.18 Cupping Cupping is the departure across the width of tape from a flat surface. The maximum cupping of a 6,35 m
39、m (0,25 in) long length of tape shall not ex- ceed 0,25 mm (0,010 in) when placed concave side down on a smooth, flat surface. The time between cutting and the measurement should be 1 h. 5.19 Opacity Opacity is a characteristic which limits the amount of transmission of light through the tape. The t
40、ape opacity shall not be less than 95 % over the wave- length range from 0,4 pm to 1,5 pm (16 pin to 59 pin). The electrical resistance of the magnetic surface shall be within the range of 5 x lo5 Sz to 5 x IO* a. 5.21 Reflectivity 5.21 .I Marker reflectivity The photo-reflective marker shall posses
41、s a reflectivity of at least 90 % compared to a reference standard, at a 60” angle of incidence of light and over the range of wavelengths from 0,4 pm to 1,5 pm (16 pin to 59 pin). The reference standard shall be constructed from a piece of aluminium AI-MS 1 Si Cu (see IS0 209-I) with a flat face di
42、mension of 30 mm (I,2 in) by 5 mm (0,20 in) with a surface roughness R, (arith- metical mean deviation) between 0,008 pm (0,32 pin) and 0,016 pm (0,63 pin) (see IS0 468). The standard should be resurfaced periodically to pre- vent a reflectivity shift due to oxidation. 5.21.2 Tape backing reflectivi
43、ty The tape backing shall possess a reflectivity not ex- ceeding 30 % of that of the reference standard when measured under the conditions specified in 5.21.1. 5.22 Dynamic frictional characteristics The force specified in 5.22.1.1, 5.22.2.1, 5.22.3.1 and 5.22.4.1 shall be the sum of the forces exer
44、ted by the 65 g (2,3 oz) mass and the dynamic friction. 5.22.1 Oxide coating to brass and chrome 5.22.1.1 Requirement The force shall be I,28 N max. (4,6 ozf max.). 5.22.1.2 Procedure The sample shall be pulled at 50 mm (2 in) per min- ute over a brass (chrome) cylinder (go-degree wrap) of diameter
45、25 mm (1 in) with a 65 g (2,3 oz) mass on the other end of the tape. The force versus time (or force versus distance) shall be plotted. Particular attention should be given to keeping the samples clean and maintaining the brass (chrome) cylinder finish 0,13 pm to 0,26 pm (5 pin to 10 pin) peak-to-peak. 5.22.2 Oxide coating to tape back surface 5.22.2.1 Requirement The force shall be 0,78 N min. (2,8 ozf min.).
