1、INTERNATIONAL STANDARD lSO/IEC 15731 First edition 1998-05-l 5 Information technology - 12,65 mm wide magnetic tape cassette for information interchange - Helical scan recording - DTF-1 format Technologies de /information - Cassette de bande magktique de 12,65 mm de large pour kchange dinformation -
2、 Enregistrement par balayage en spirale - Format DTF- 1 Reference number ISO/IEC 15731:1998(E) ISO/IEC 15731:1998 (E) Contents Section 1 - General 1 1 Scope 1 2 Conformance 1 2.1 Magnetic tape cassette 1 2.2 Generating system 1 2.3 Receiving system 1 3 Normative references 1 4 Definitions 4.1 Absolu
3、te block number 4.2 a.c. erase 4.3 algorithm 4.4 Append file 4.5 Append volume 4.6 Average Signal Amplitude (ASA) 4.7 azimuth 4.8 back surface 4.9 bit cell 4.10 block 4.11 Block Management Table (BMT) 4.12 byte 4.13 cassette 4.14 compressed data 4.15 Control Track 4.16 flux transition position 4.17
4、flux transition spacing 4.18 Logical track set ID 4.19 Logical volume 4.20 magnetic tape 4.21 Master Standard Reference Tape (MSRT) 4.22 physical recording density 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 0 ISO/IEC 1998 All rights reserved. Unless otherwise specified, no part of this publicatio
5、n 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 Copyright Office l Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii 0 ISO/IEC ISO/IEC 1573
6、1:1998 (E) 4.23 Reference Field (RF) 4.24 Secondary Standard Reference Tape (SSRT) 4.25 Standard Reference Amplitude (SRA) 4.26 Standard Reference Current (Ir) 4.27 Tape Reference Edge 4.28 Test Recording Current (TRC) 4.29 track 4.30 track angle 4.31 Track Set 4.32 Typical Field (TF) 4.33 Unique Id
7、entifier (UID) 4.34 word 5 Conventions and notations 5.1 Representation of numbers 5.2 Names 6 Acronyms 7 Environment and safety 7.1 Testing environment 7.2 Operating environment 7.3 Storage environment 7.4 Transportation 7.5 Safety 7.6 Flammability Section 2 - Requirements for the case 8 Dimensiona
8、l and mechanical characteristics of the case 8.1 General 8.2 Type S cassette 8.2.1 Overall dimensions 8.2.2 Holding areas 8.2.3 Window 8.2.4 Label areas 8.2.5 Datum areas and datum holes 8.2.6 Support areas 8.2.7 Guiding grooves 8.2.8 Recognition holes 8.2.9 Write-inhibit plug 8.2.10 Pre-positioning
9、 surface 8.2.11 Cassette lid 8.2.12 Cassette reel lock 8.2.13 Reel access holes 8.2.14 Reels 8.2.15 Position of the tape in the case 8.2.16 Tape path zone 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 5 5 5 6 6 6 6 7 7 8 9 10 11 11 12 12 12 13 14 . . . 111 ISO/IEC 15731:1998 (E) 0 lSO/lEC 8.2.17 Tape access cavity
10、8.3 Type L cassette 8.3.1 Overall dimensions 8.3.2 Holding areas 8.3.3 Window 8.3.4 Label areas 8.3.5 Datum areas and datum holes 8.3.6 Support areas 8.3.7 Guiding grooves 8.3.8 Recognition holes 8.3.9 Write-inhibit plug 8.3.10 Pre-positioning surface 8.3.11 Cassette lid 8.3.12 Cassette reel lock 8.
11、3.13 Reel access holes 8.3.14 Reels 8.3.15 Position of the tape in the case 8.3.16 Tape path zone 8.3.17 Tape access cavity 8.3.18 Cavity for compatibility with Type S cassette Section 3 - Requirements for the unrecorded tape 9 Mechanical, physical and dimensional characteristics of the tape 9.1 Mat
12、erials 9.2 Tape length 9.3 Tape widths 9.4 Width and position of splicing tape 9.5 Discontinuity 9.6 Tape thickness 9.7 Longitudinal curvature 9.8 Out-of-plane distortions 9.9 Coating adhesion 9.10 Layer-to-layer adhesion 9.11 Tensile strength 9.11.1 Breaking strength 9.11.2 Yield strength 9.11.3 St
13、rength of Splice 9.12 Residual elongation 9.13 Electrical resistance of the coated surfaces 9.14 Tape wind 10 Magnetic recording characteristics 10.1 Typical Field TFI 10.2 Average Signal Amplitude(ASA) 10.3 Resolution 10.4 Signal-to-noise ratio (S/N) 14 29 29 29 30 30 30 30 31 32 33 34 34 35 35 36
14、36 37 38 38 53 53 53 54 54 54 54 54 54 54 55 55 55 55 55 56 56 56 56 56 57 57 57 57 iv 0 ISO/IEC ISO/IEC 15731:1998 (E) 10.5 Ease of erasure 10.6 Tape quality 10.6.1 Missing pulses 10.6.2 Missing pulse zone 10.7 Inhibitor tape Section 4 - Requirements for an interchanged tape 11 Format for helical t
15、racks 11.1 General description of the write data path 11.2 Formation of a Logical Track Set 11.2.1 Types of information track sets 11.2.2 Generation of a Logical Track Set 11.2.3 Subcode data field 11.2.4 BMT 11.2.5 Data and information field definitions 11.3 Track Set information 11.3.1 Loading the
16、 Product Code Arrays 11.4 Product code array processing 11.4.1 Error correction method 11.4.2 Error correction coding for Cl Parity 11.5 Track assignments 11.5.1 Sectors 11.5.2 Sync Blocks 11.5.3 Track interleave 11.5.4 Track Sync Blocks 11.5.5 Byte interleave across Sync Blocks 11.5.6 Randomization
17、 11.6 Formation of the contents of a helical track 11.6.1 Sector details (figure 50) 11.7 Channel bit coding (annex B) 11.7.1 General 11.7.2 Interleaved-NRZI 12 Track geometry 12.1 General 12.2 Helically recorded tracks 12.2.1 Location of the tracks 12.2.2 Track width 12.2.3 Track angle 12.2.4 Track
18、 pitch 12.2.5 Location of elements in the helical track 12.2.6 Location of the Data Area Reference Point 12.2.7 Straightness of tracks 12.2.8 Azimuth angles 12.2.9 Tracking Pilot Signal (TPS) 57 57 57 58 58 59 59 59 59 59 61 63 64 65 69 69 71 71 71 73 73 73 74 75 76 76 77 77 79 79 79 79 79 79 79 80
19、80 80 81 81 81 81 81 V ISO/IEC 15731:1998 (E) 0 ISO/IEC 12.2.10 Amplitude of servo signals 12.3 Longitudinal tracks geometry 12.3.1 Control Track 12.3.2 Time Code Track signals recording position 13 Method of recording helical tracks 82 13.1 Physical recording density 82 13.2 Record current optimiza
20、tion 82 13.3 Efficiency of erasure 82 14 Method of recording longitudinal tracks 14.1 Overview 14.2 Control Track 14.2.1 Signal 14.2.2 Polarity of magnetisation (figure 53) 14.2.3 Alignment 14.2.4 Read signal amplitude 14.2.5 Quality of the Control Track 14.3 Time Code Track 14.3.1 Method of recordi
21、ng the Time Code Track 14.3.2 Physical recording density 14.3.3 Bit shift 14.3.4 Read signal amplitude 14.3.5 Quality of the Time Code Track 14.4 Format for the Time Code Track 14.4.1 Count bits 14.4.2 Phase bit 14.4.3 Synchronizing pattern 14.4.4 Supplemental Data 14.4.5 Extent of Time Code Section
22、 5 - Requirements for recorded information 84 15 Recorded information 15.1 Recording area (figure 54) 15.2 Magnetic tape layout (figure 55) 15.2.1 Valid data areas 15.2.2 Invalid data areas 15.3 Physical TSID 15.3.1 Structure surrounding the VSIT area 15.3.2 Structure of the DIT area 15.3.3 Structur
23、e of the User Data Area 81 81 81 82 82 82 82 82 82 82 83 83 83 83 83 83 84 84 84 84 84 84 84 84 84 84 85 85 85 85 87 87 88 Section 6 - Write operations 89 16 Write retry sequence 89 vi 0 ISO/IEC 17 Append file operation 89 17.1 Append volume 89 17.2 Append write 90 17.3 Overwrite 90 17.4 File extens
24、ion 91 Annexes A - Measurement of Signal-to-Noise Ratio B - Representation 819 coding patterns C - Recommendations for Transportation D - Inhibitor Tape ISO/IEC 15731:1998 (E) 93 94 98 99 vii ISOilEC 15731:1998 (E) 0 ISO/IEC Foreword IS0 (the International Organization for Standardization) and IEC (
25、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 part
26、icular 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 esta
27、blished a joint technical committee, ISO/IEC JTC 1. 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 St
28、andard ISO/IEC 15731 was prepared by ECMA (as Standard ECMA-248) and was adopted, under a special “fast-track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its approval by national bodies of IS0 and IEC. Annexes A, and B form an integral part of thi
29、s International Standard. Annexes C and D are for information only. IS0 and IEC draw attention to the fact that it is claimed that compliance with this International Standard may involve the use of patents concerning the Master Standard Reference Tape and Secondary Standard Reference Tape given in c
30、lause 4. IS0 and IEC take no position concerning the evidence, validity and scope of this patent right. The holder of this patent right has assured IS0 and IEC that he is willing to negotiate licences under reasonable and non- discriminatory terms and conditions with applicants throughout the world.
31、 In this respect, the statement of the holder of this patent right is registered with IS0 and IEC. Information may be obtained from: Sony Corporation Contracts and Licensing Division Tokyo international P.O. Box 5 100 Tokyo 100-3 1 Japan Attention is drawn to the possibility that some of the element
32、s of this International Standard may be the subject of patent rights other than those identified above. IS0 and IEC shall not be held responsible for identifying any or all such patent rights. . . Vlll INTERNATIONAL STANDARD 0 ISO/IEC ISO/IEC 15731:1998 (E) Information technology - 12,65 mm wide mag
33、netic tape cassette for information interchange - Helical scan recording - DTF-1 format Section 1 - General 1 Scope This International Standard specifies the physical and magnetic characteristics of magnetic tape cassettes, using magnetic tape 12,65 mm wide so as to provide physical interchange of s
34、uch cassettes between drives. It also specifies the quality of the recorded signals, the recording method and the recorded format, called Digital Tape Format-l (DTF-I), thereby allowing data interchange between drives by means of such cassettes. The format supports variable length Logical Records, h
35、igh speed search, and the use of a registered algorithm for data compression. This International Standard specifies two sizes of cassette. For the purposes of this International Standard the larger cassette is referred to as Type L, and the smaller as Type S. Together with a standard for volume and
36、file structure, e.g. IS0 1001, this International Standard provides for full data interchange between data processing systems. 2 Conformance 2.1 Magnetic tape cassette A claim of conformance with this International Standard shall specify the Type of cassette. It shall be in conformance with this Int
37、ernational Standard if - the case meets all the requirements of clause 4 and clauses 6 to 10 for that Type - the recording on the tape meets the requirements of clauses 11 to 17 2.2 Generating system A claim of conformance with this International Standard shall specify which Type(s) of cassette is (
38、are) supported. A system generating a magnetic tape cassette for interchange shall be in conformance with this International Standard if all the recordings that it makes, meet the mandatory requirements of this International Standard. A claim of conformance with this International Standard shall sta
39、te whether or not one, or more, registered algorithm(s) is (are) implemented and, if so, the registered number(s) of (all) the implemented algorithm(s). 2.3 Receiving system A claim of conformance with this International Standard shall specify which Type(s) of cassette is (are) supported. A system r
40、eceiving a magnetic tape cassette for interchange shall be in conformance with this International Standard if it is able to handle any recording made on the tape according to this International Standard, and a claim of conformance shall state whether or not one, or more, registered algorithm(s) is (
41、are) implemented and, if so, the registered number(s) of (all) the implemented algorithm(s). 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, the editions indicat
42、ed 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 indicated below. Members of IEC and IS0 maintain registers of currently valid Inter
43、national Standards. IS0 527 (all parts), IS0 1001: 1986, ISO/IEC 11576: 1994, IEC 950:1991, JIS-B-7502, SMPTE timecode: Plastics - Determination of tensile properties. Information processing - File structure and lubelling of magnetic tapes for information interchange. Information technology - Proced
44、ure for the registration of algorithms for the lossless compression of data. Safety of information technology equipment. Characteristics of plastic goods. (C98.12 : time and control code for video and audio tape for 525/60 television system). ISO/IEC 15731:1998(E) OISO/IEC 4 Definitions For the purp
45、oses of this International Standard, the following definitions apply. 4.1 Absolute block number: A number N allocated to each block, indicating that the block is the Nth block from the beginning of the Logical volume containing it. 4.2 a.c. erase: A process of erasure utilizing alternating magnetic
46、fields of decaying intensity. 4.3 algorithm: A set of rules for transforming the logical representation of data. 4.4 Append file: A new file added from the End of Data (EOD) of a Logical volume. 4.5 Append volume: A Logical volume added after the last Logical volume recorded on the cassette. 4.6 Ave
47、rage Signal Amplitude (ASA): The average peak-to-peak value of the signal output of a read head measured over a minimum of 1,40 mm of track, exclusive of missing pulses. 4.7 azimuth: The angular deviation, in degrees of arc, of the recorded flux transitions on a track from the line normal to the tra
48、ck centreline. 4.8 back surface: The surface of the tape opposite to the magnetic coating used to record data. 4.9 bit cell: A distance along the track allocated for the recording of a Channel bit. 4.10 block: A unit of data which is sent to the tape controller when a single write command is execute
49、d. 4.11 Block Management Table (BMT): A table included in each Track Set to manage blocks contained in that Track Set. 4.12 byte: An ordered set of bits acted upon as a unit. 4.13 cassette: A case containing magnetic tape stored on twin reels. 4.14 compressed data: A representation of host-transmitted data after transformation by a data compression algorithm. 4.15 Control Track: A track used for recording the servo control signals. 4.16 flux transition position: That point along a track on the magnetic tape that
