1、BRITISH STANDARD BS ISO/IEC 3788:1990 Implementation of ISO/IEC3788:1990 Information processing 9-track, 12,7mm (0,5in) wide magnetic tape for information interchange using phase encoding at126 ftpmm(3200ftpi) 63cpmm(1600 cpi) UDC 681.327.636BSISO/IEC3788:1990 This British Standard, having been prep
2、ared under the directionof the Information Technology Systems StandardsPolicy Committee, waspublishedunder the authorityofthe Board of BSI andcomes intoeffect on 31 October1990 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference IST/4 Draft for comment87
3、/65766DC ISBN 0 580 19071 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Information Technology Systems Standards Policy Committee (IST/-) to Technical Committee IST/4, upon which the following bodies were represented: British Compute
4、r Society British Telecommunication plc Department of Trade and Industry (National Physical Laboratory) EEA (The Electronics and Business Equipment Association) HM Customs and Excise Institute of Quality Assurance Institution of Electrical Engineers Institution of Mechanical Engineers Post Office Am
5、endments issued since publication Amd. No. Date CommentsBSISO/IEC3788:1990 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO/IEC 3788 1BSISO/IEC3788:1990 ii BSI 12-1999 National foreword This British Standard reproduces verbatim ISO/I
6、EC3788:1990 and implements it as the UK national standard. This British Standard is published under the direction of the Information Technology Systems Standards Policy Committee whose Technical Committee IST/4 has the responsibility to: aid enquirers to understand the text; present to the responsib
7、le international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from BSI
8、Sales Department, BSI, Linford Wood, Milton Keynes, MK146LE. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from
9、 legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO/IEC title page, pages ii to iv, pages 1 to 13 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicat
10、ed in the amendment table on the inside front cover.ISO/IEC3788:1990(E) ii BSI 12-1999 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 General requirements 2 5 Recording 2 6 Track configuration 4 7 Data representation 4 8 Format of the tape 4 9 Quality of recording fo
11、r data interchange 6 Annex A (normative) Procedure and instrumentation for measuring fluxtransitionspacing 7 Annex B (informative) Determination of the erase magnetic field direction 12 Annex C (informative) Storage and transportation 12 Figure 1 Track layout 5 Figure A.1 Example of amplifier differ
12、entiator 9 Figure A.2 Calibration equipment setup 10 Figure A.3 Measurement equipment setup 11 Figure A.4 Test pattern display 12 Descriptors: Data processing, information interchange, data recording devices, magnetic tapes,9-tracks, half-inch magnetic tapes, specifications, dimensions, track format
13、s.ISO/IEC3788:1990(E) BSI 12-1999 iii 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
14、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 li
15、aison 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 JTC1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an I
16、nternational Standard requires approval by at least75% of the national bodies casting a vote. International Standard ISO/IEC3788 was prepared by Joint Technical Committee ISO/IEC JTC1, Information technology. Annex A forms an integral part of this International Standard.Annex B andAnnex C are for in
17、formation only.iv blankISO/IEC3788:1990(E) BSI 12-1999 1 1 Scope This International Standard specifies a format and recording standard for9-track,12,7mm(0,5in) magnetic tape to be used for data interchange between information processing systems, communication systems, and associated equipment utiliz
18、ing the7-bit coded character set (seeISO646), its extension inISO2022 where required, or an8-bit coded character set (seeISO4873). Magnetic labelling for use on magnetic tape is the subject ofISO1001. The magnetic tape and reel to be used shall conform toISO1864 and/orISO8064. NOTE 1Numeric values i
19、n the SI and/or Imperial measurement system in this International Standard may have been rounded off and therefore are consistent with, but not exactly equal to, each other. Either system may be used, but the two should be neither intermixed nor reconverted. The original design was made using the Im
20、perial measurement system. 2 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
21、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 646:1983, Information processing ISO7-bit
22、coded character set for information interchange. ISO 1001:1986, Information processing File structure and labelling of magnetic tapes for information interchange. ISO 1864:1985, Information processing Unrecorded12,7mm(0,5in) wide magnetic tape for information interchange 32ftpmm(800ftpi) NRZ1,126ftp
23、mm(3200ftpi) phase encoded and356ftpmm(9042ftpi) NRZ1. ISO 2022:1986, Information processing ISO7-bit and8-bit coded character sets Coded extension techniques. ISO 4873:1986, Information processing ISO8-bit code for information interchange Structure and rules for implementation. ISO 8064:1985, Infor
24、mation processing Reels for12,7mm(0,5in) wide magnetic tapes Sizes16,18 and22. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 magnetic tape a tape which will accept and retain magnetic signals intended for input, output and storage purposes on com
25、puters and associated equipment 3.2 reference tape a tape which has been selected for given properties for use in calibration 3.3 master standard reference tape a reference tape selected as a standard for signal amplitude NOTE 2A Master Standard Reference Tape has been established by the US National
26、 Institute of Standards and Technology (NIST). 3.4 secondary standard reference tape a tape the performance of which is known and stated in relation to that of the Master Standard Reference Tape NOTE 3Secondary Standard Reference Tapes are available from NIST (Office of Standard Reference Materials,
27、 RoomB311, Chemistry Building, NBS, Gaithersburg, Md20899, USA) under part number SRM3200. It is intended that these be used for calibration of tertiary tapes for use in routine calibration. 3.5 typical field in the plot of Average Signal Amplitude against recording field at the specified flux trans
28、ition density, the Typical Field is the minimum field that causes an Average Signal Amplitude equal to95% of the maximum Average Signal Amplitude 3.6 reference field the Typical Field of the Master Standard Reference Tape at the specified recording density 3.7 standard reference amplitude the averag
29、e peak-to-peak signal amplitude derived from the Master Standard Reference Tape in the NIST measurement system under the recording conditions specified in5.6.1ISO/IEC3788:1990(E) 2 BSI 12-1999 3.8 reference edge the edge further from an observer, when a tape is lying flat with the magnetic surface u
30、ppermost and the direction of movement for recording is from left to right (seeFigure 1) 3.9 in-contact an operating condition in which the magnetic surface of a tape is in contact with a magnetic head 3.10 track a longitudinal area on a tape along which a series of magnetic signals may be recorded
31、3.11 row nine transversely related locations (one in each track) in which bits are recorded 3.12 physical recording density the number of recorded flux transitions per unit length of track, ftpmm (ftpi) 3.13 data density the number of data characters stored per unit length of tape, cpmm (cpi) 3.14 s
32、kew within a row, the maximum displacement of any location from any other location measured as the distance between two perpendiculars to the reference edge through said locations 3.15 position of a flux transition the point which exhibits the maximum free-space flux density normal to the tape surfa
33、ce 4 General requirements 4.1 Operating environment Tapes used for data interchange shall be operated under the following conditions: temperature:16 C to32C(60 F to90 F); relative humidity:20% to80%; wet bulb temperature: not greater than25C(78 F). Conditioning before operating: If a tape has been e
34、xposed during storage and/or transportation to conditions outside the above values, it should be conditioned for a period of2h to12h depending upon the extent of exposure. 4.2 Storage and transportation The recommendations for storage and transportation environment are specified in Annex C. Responsi
35、bility for ensuring that adequate precautions against damage are taken during shipment shall be with the sender (seeAnnex C). 4.3 Wind tension For interchange, the tape winding tension shall be between2,0N and3,6N(7ozf to13ozf). 5 Recording 5.1 Method of recording The recording method shall be phase
36、 encoding, described as follows: 5.1.1 A ONE is represented by a flux transition to the polarity of the interblock gap, when reading in the forward direction. 5.1.2 A ZERO is represented by a flux transition to the polarity opposite to that of the interblock gap, when reading in the forward directio
37、n. 5.1.3 Additional flux transitions shall be written at the nominal midpoint between bit flux transitions, as defined in5.1.1 and5.1.2, if required to establish the proper polarity for the succeeding bits. These flux transitions shall be called phase flux transitions. 5.1.4 Interblock gaps shall be
38、 of the same polarity as erase (see5.7). 5.2 Density of recording The nominal physical recording density shall be126ftpmm(3200ftpi). The resulting nominal flux transition spacing is7,9354m(312,54in). A density of63ftpmm(1600ftpi) is also used for specific measurements. 5.3 Average flux transition sp
39、acing The following requirements shall be measured by reading a tape that has been continuously and evenly recorded at63ftpmm(1600ftpi) in phase in all tracks. The resulting nominal bit flux transition spacing is15,874m(6254in). 5.3.1 The long-term average (static) flux transition spacing shall be w
40、ithin 4% of the nominal spacing. This average shall be measured over a minimum of5 10 5successive flux transitions. 5.3.2 The short-term average (dynamic) flux transition spacing, when referred to a particular flux transition spacing, is defined as the average of that flux transition spacing and the
41、 preceding three flux transition spacings.ISO/IEC3788:1990(E) BSI 12-1999 3 The short-term average flux transition spacing shall be within 10% of the long-term average flux transition spacing. In addition, the rate of change of the short-term average flux transition spacing shall not exceed0,5%. 5.4
42、 Instantaneous flux transition spacing The instantaneous spacing between flux transitions may be influenced by the reading and writing process, the bit sequence recorded (pulse crowding effects) and other factors. Instantaneous spacings between flux transitions shall meet the following five conditio
43、ns, when tested on the reference read chain (seeAnnex A): a) The spacing between successive data flux transitions without an intervening phase flux transition shall be between85% and108% of the corresponding short-term average flux transition spacing. b) The spacing between successive data flux tran
44、sitions with an intervening phase flux transition shall be between93% and112% of the corresponding short-term average flux transition spacing. c) The spacing between a data flux transition and any adjacent phase flux transition shall be between44% and62% of the corresponding short-term average flux
45、transition spacing. d) The average spacing between actual data flux transitions in a sequence of flux transitions at63 per millimetre(1600perinch) and the predicted position of those data bits relative to flux transitions at126 per millimetre(3200 perinch) preceding or succeeding the sequence shall
46、not exceed 6% of the corresponding short-term average spacing. e) The equipment used for recording tapes at63 characters per millimetre(1600 characters per inch) and the magnetic tape to be used for interchange shall fulfil the requirements of a) to d) when tested under the conditions specified in t
47、he reference read chain(seeAnnex A). 5.5 Skew The skew shall be less than15,874m(6254in). This condition is required to be satisfied for both flux transition polarities and for each row. 5.6 Signal amplitude 5.6.1 Standard Reference Amplitude The Standard Reference Amplitude is the average peak-to-p
48、eak signal amplitude derived from the Master Standard Reference Tape on the qualified measurement system at the density of126ftpmm(3200ftpi) and the recording current, I r , of1,8 I f . The signal amplitude shall be averaged over4000 flux transitions, and shall be measured on the read-while-write pa
49、ss. The reference current, I f , is the current which produces the Reference Field. 5.6.2 Average signal amplitude The average peak-to-peak signal amplitude of an interchanged tape at126ftpmm(3200ftpi) shall be between65% and150% of the Standard Reference Amplitude. The average peak-to-peak signal amplitude at63ftpmm(1600ftpi) shall be less than300% of the Standard Reference Amplitude. Averaging shall be done over a minimum of4000flux transitions, which for the interchange tape, may be segmented into blocks. Averaging sh
