1、BRITISH STANDARD BS ISO/IEC 12246:1993 Implementation of ISO/IEC12246:1993 Information technology 8mm wide magnetic tape cartridge dual azimuth format for information interchange Helical scan recording UDC 681.327.636BSISO/IEC 12246:1993 This British Standard, having been prepared under the directio
2、nof the Information Systems Technology Standards Policy Committee, was publishedunder the authorityofthe Standards Boardand comes into effect on 15June1994 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference IST/4 Draft for comment 92/66914 DC ISBN 0 580
3、 23193 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Information Systems Technology Standards Policy Committee (IST/-) to Technical Committee IST/4, upon which the following bodies were represented: British Computer Society ICI Image
4、data Institute of Quality Assurance Institution of Electrical Engineers International Computers Limited Kodak Limited Amendments issued since publication Amd. No. Date CommentsBSISO/IEC12246:1993 BSI 01-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword vii
5、Text of ISO/IEC 12246 1BSISO/IEC 12246:1993 ii BSI 01-2000 National foreword This British Standard reproduces verbatim ISO/IEC12246:1993 and implements it as the UK national standard. This British Standard is published under the direction of the Information Systems Technology Standards Policy Commit
6、tee whose Technical Committee IST/4 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments an
7、d promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, Publications, BSI, Linford Wood, Milton Keynes, MK146LE. A British Standard does not purport to include all the necessary provisions of a contract. Users of Bri
8、tish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theISO/IEC title page, pages ii to viii, pages1 to6
9、0 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO/IEC 12246:1993 (E) ii BSI 01-2000 Contents Page Foreword vii Introduction 1 Section 1. General 1 Scope 2 2 Con
10、formance 2 3 Normative references 2 4 Definitions 2 4.1 a.c. erase 2 4.2 algorithm 2 4.3 Average Signal Amplitude 2 4.4 azimuth 2 4.5 back surface 2 4.6 bit cell 2 4.7 byte 3 4.8 cartridge 3 4.9 compressed data 3 4.10 Cyclic Redundancy Check (CRC) Character 3 4.11 Error Correcting Code (ECC) 3 4.12
11、flux transition position 3 4.13 flux transition spacing 3 4.14 logical record 3 4.15 magnetic tape 3 4.16 Master Standard Reference Tape 3 4.17 Physical Beginning of Tape (PBOT) 3 4.18 Physical End of Tape (PEOT) 3 4.19 physical recording density 3 4.20 Secondary Reference Amplitude 3 4.21 Secondary
12、 Reference Field 4 4.22 Secondary Standard Reference Tape 4 4.23 Standard Reference Current 4 4.24 Tape Reference Edge 4 4.25 Test Recording Current 4 4.26 track 4 4.27 Typical Field 4 4.28 uncompressed data 4 5 Environment and safety 4 5.1 Testing environment 4 5.2 Operating environment 4 5.3 Stora
13、ge environment 5 5.4 Transportation 5 5.5 Safety 5 5.6 Flammability 5 Section 2. Cartridge 6 Dimensional and mechanical characteristics of the cartridge 6 6.1 General 6 6.2 Overall dimensions 6 6.3 Holding areas 6 6.4 Cartridge insertion 7 6.5 Window 7 6.6 Loading grips 7ISO/IEC12246:1993(E) BSI 01-
14、2000 iii Page 6.7 Label areas 8 6.8 Datum areas and datum holes 8 6.9 Support areas 9 6.10 Recognition holes 9 6.11 Write-inhibit hole 10 6.12 Pre-positioning surfaces 10 6.13 Cartridge lid 10 6.14 Cartridge reel lock 11 6.15 Reel access holes 12 6.16 Interface between the reels and the drive spindl
15、es 12 6.17 Light path 13 6.18 Position of the tape in the case 13 6.19 Tape path zone 13 6.20 Tape access cavity 14 6.21 Tape access cavity clearance requirements 14 Section 3. Requirements for the unrecorded tape 7 Mechanical, physical and dimensional characteristics of the tape 31 7.1 Materials 31
16、 7.2 Tape length 31 7.2.1 Magnetic tape 31 7.2.2 Leader and trailer tapes 31 7.2.3 Splicing tape 31 7.3 Width 31 7.4 Discontinuities 31 7.5 Thickness 31 7.5.1 Thickness of magnetic tape 31 7.5.2 Thickness of leader and trailer tape 31 7.6 Longitudinal curvature 31 7.7 Cupping 31 7.8 Coating adhesion
17、 32 7.9 Layer-to-layer adhesion 32 7.10 Tensile strength 32 7.10.1 Breaking strength 33 7.10.2 Yield strength 33 7.11 Residual elongation 33 7.12 Electrical resistance of the surface 33 7.13 Tape winding 34 7.14 Light transmittance of tape 34 8 Magnetic recording performance 34 8.1 Test conditions 3
18、4 8.2 Typical Field 34 8.3 Signal amplitude 34 8.4 Resolution 34 8.5 Narrow-band signal-to-noise ratio 34 8.5.1 Requirement 34 8.5.2 Procedure 34 8.6 Ease of erasure 35 8.7 Tape quality 35 8.7.1 Missing pulses 35ISO/IEC 12246:1993 (E) iv BSI 01-2000 Page 8.7.2 Missing pulse zone 35 8.8 Inhibitor tap
19、e 35 Section 4. Requirements for an interchanged tape 9 Format 36 9.1 General 36 9.2 Information Matrix 36 9.2.1 Loading of the Information Matrix 37 10 Method of recording 40 10.1 Physical recording density 40 10.1.1 Long-term average bit cell length 40 10.1.2 Short-term average bit cell length 40
20、10.1.3 Rate of change 40 10.2 Bit shift 40 10.3 Read signal amplitudes 40 10.3.1 Amplitude of data signals 40 10.3.2 Amplitude of servo signals 41 10.4 Erasure 41 11 Track geometry 41 11.1 Track positions 41 11.2 Track pitch 42 11.2.1 Adjacent track pitch 42 11.2.2 Average track pitch 42 11.3 Track
21、width 42 11.4 Track angle 42 11.5 Straightness of track edge 42 11.6 Azimuth 42 12 Format of a track 42 12.1 Channel Bit 42 12.2 Information Segment 42 12.2.1 Bit Synchronization Field 42 12.2.2 Information Segment Number 43 12.2.3 Information Segment field 43 12.3 Information Block 43 12.4 Physical
22、 track types 44 12.4.1 T1 and T2 track layouts 44 12.5 Search Field Zones 45 12.5.1 Search Field Data Zones 45 12.5.2 Search Field Zone Sequence of recording 46 12.6 Servo Zone 47 12.6.1 Servo Zone 1 47 12.6.2 Servo Zone 2 47 12.6.3 Servo Zone 3 47 12.7 Information Tracks 47 12.7.1 Format Track 47 1
23、2.7.2 Data Track 47 12.7.3 Long Tape Mark Track 47 12.7.4 Gap Track 47 12.7.5 End of Data Track 47 13 Tape Mark 48ISO/IEC12246:1993(E) BSI 01-2000 v Page 13.1 Long Tape Mark 48 13.2 Short Tape Mark 48 14 End of Data 48 15 ID Information 48 15.1 Physical Block ID 48 15.2 Logical Block ID 48 15.3 Logi
24、cal Record ID 48 15.4 Block type 49 15.4.1 Data Block 49 15.4.2 Gap Block 50 15.4.3 Format Block 50 15.4.4 Long/Short Tape Mark Block 50 15.4.5 End of Data Block 51 16 Rewritten Information Blocks 51 17 Physical Tape Format 51 17.1 Initial Erased Area 52 17.2 Logical Beginning of Tape Area (LBOT Are
25、a) 52 17.3 Usable area of the tape 52 Annex A (normative) Measurement of light transmittance of tape and leaders 53 Annex B (normative) Measurement of bit shift 55 Annex C (normative) Representation of 8-bit bytes by 10-bit patterns 57 Annex D (informative) Recommendations for transportation 60 Anne
26、x E (informative) Inhibitor tape 60 Figure 1 Tape cartridge assembly top view (lid open) 15 Figure 2 Tape cartridge assembly bottom view (lid closed) 15 Figure 3 Top side (lid closed) 16 Figure 4 Bottom side, datum and support areas 17 Figure 5 Bottom side (lid removed) 18 Figure 6 Details of datum
27、and recognition holes 19 Figure 7 Cross-sections of light path holes, recognition holes and write-inhibit hole 20 Figure 8 Lid 21 Figure 9 Lid release insertion channel 22 Figure 10 Lid release requirement 23 Figure 11 Reel lock release 24 Figure 12 Direction of force needed to unlock the reel lock
28、25 Figure 13 Direction of force needed to unlock the lid lock 25 Figure 14 Direction of force needed to open the lid 26 Figure 15 Light path and light window 26 Figure 16 Internal tape path and light path 27 Figure 17 Cartridge reel 28 Figure 18 Interface with drive spindle 29 Figure 19 Tape access
29、cavity clearance 30 Figure 20 Setup for measuring coating adhesion 32 Figure 21 Setup for measuring electrical resistance 33 Figure 22 Information Matrix 36 Figure 23 Track layout and track location 41 Figure 24 Information Segment Layout 42ISO/IEC 12246:1993 (E) vi BSI 01-2000 Page Figure 25 Segmen
30、t field partitioning of the Information Matrix 44 Figure 26 T1 and T2 track layouts 44 Figure 27 Search Field Data Zone 45 Figure 28 Physical Tape Layout 51 Figure A.1 Optical arrangement 54 Figure A.2 Measuring circuitry 55 Figure B.1 Measurement of waveform 56 Table 1 Representation of the Informa
31、tion Segment Numbers 43ISO/IEC12246:1993(E) BSI 01-2000 vii 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
32、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 n
33、on-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 JTC1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for votin
34、g. Publication as an International Standard requires approval by at least75% of the national bodies casting a vote. International Standard ISO/IEC12246 was prepared by the European Computer Manufacturers Association (ECMA) (as Standard ECMA-169) and was adopted, under a special “fast-track procedure
35、”, by Joint Technical Committee ISO/IEC JTC1, Information technology, in parallel with its approval by national bodies of ISO and IEC. Annex A,Annex B andAnnex C form an integral part of this International Standard.Annex D,Annex E andAnnex F are for information only.viii blankISO/IEC12246:1993(E) BS
36、I 01-2000 1 Introduction ISO/IEC have produced a series of International Standards for cassettes and cartridges containing magnetic tapes of different width and characteristics. The first International Standards (e.g.ISO3407, ISO4057, ISO8063, ISO8462, ISO/IEC9661, ISO/IEC11559) dealt with media des
37、igned for the digital recording of data for storage and processing in data processing systems. Later, other magnetic media, originally developed for audio and video applications, have been considered for use in data processing applications for storage as well as for information interchange. The reco
38、rding method known as helical scan recording, together with new types of magnetic tapes, allows to achieve capacities of more than1 gigabyte of user data. International Standards ISO/IEC10777, ISO/IEC11319, ISO/IEC11321, ISO/IEC11557, ISO/IEC12247 and ISO/IEC12248 deal with such magnetic tape cartri
39、dges. This International Standard is based on ISO/IEC11319 with extensions and modifications which specify the additional features of the Dual Azimuth format. The specifications of the tape, cartridge, recorded signal, recording method and much of the recorded format are identical with those in ISO/
40、IEC11319. It is not intended that this International Standard replace ISO/IEC11319. Existing drives and cartridges which conform to ISO/IEC11319 will continue to do so and will not conform to this International Standard. Future drives and tapes which conform to ISO/IEC11319 may, in addition, conform
41、 to this International Standard, but only if they support those features herein which are not in ISO/IEC11319.ISO/IEC 12246:1993 (E) 2 BSI 01-2000 Section 1. General 1 Scope This International Standard specifies the physical and magnetic characteristics of an8mm wide magnetic tape cartridge to enabl
42、e interchangeability of such cartridges. It also specifies the quality of the recorded signals, the format and the recording method, thus allowing, together with ISO1001 for Magnetic Tape Labelling, full data interchange by means of such magnetic tape cartridges. It is based on ISO/IEC11319, but use
43、s Dual Azimuth Recording to allow the raw capacity to be doubled. The format supports variable length Logical Records, high speed search, and the use of a registered data compression algorithm. 2 Conformance A magnetic tape cartridge conforms to this International Standard if it satisfies all mandat
44、ory requirements specified herein. The tape requirements shall be satisfied throughout the extent of the tape. 3 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, th
45、e editions indicated were 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 editions of the standards listed below. Members of IEC and ISO maintain registers of curren
46、tly valid International Standards. ISO/R 527:1966, Plastics Determination of tensile properties. ISO 1001:1986, Information processing File structure and labelling of magnetic tapes for information interchange. ISO 1302:1992, Technical drawings Method of indicating surface texture. ISO/IEC 11319:199
47、3, Information technology 8mm wide magnetic tape cartridge for information interchange Helical scan recording. ISO/IEC 11576:1993, Information technology Procedure for the registration of algorithms for the lossless compression of data. IEC 950:1991, Safety of information technology equipment, inclu
48、ding electrical business equipment. 4 Definitions For the purposes of this International Standard, the following definitions apply. 4.1 a.c. erase a process of erasure utilizing alternating magnetic fields of decaying level 4.2 algorithm a set of rules for transforming the logical representation of
49、data 4.3 average signal amplitude the average peak-to-peak value of the signal output of the read head measured over a minimum of1,40mm of track, exclusive of missing pulses 4.4 azimuth the angular deviation, in degrees of arc, of the recorded flux transitions on a track from the line normal to the track centreline 4.5 back surface the surface of the tape opposite to the magnetic coating used to record data 4.6 bit cell a distance along the track allocated for the recording of a Channel Bi
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