1、Standard ECMA-2462ndEdition - June 1998Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.ch8 mm Wide Magnetic TapeCartridge for InformationInterchange - Helical ScanRecording - AIT-1 Format.Standard EC
2、MA-246June 1998Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.chMB E-246-ii.doc 01-07-98 12,278 mm Wide Magnetic TapeCartridge for InformationInterchange - Helical ScanRecording - AIT-1 Format.Brief
3、 HistoryTechnical Committee ECMA TC17 has produced a series of ECMA Standards for magnetic tape cassettes andcartridges of different widths, e.g. 12,7 mm, 8 mm, 6,35 mm and 3,81 mm. In each series, the standards correspondto specific types of application and user requirements. Enhanced and new media
4、 also correspond to advancements indrive technology. The series of helically recorded cartridges with a magnetic tape of 8 mm width comprises thefollowing standards.ECMA-145 (1990) 8 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical RecordingISO/IEC 11319ECMA-169 (1992) 8 mm Wide
5、 Magnetic Tape Cartridge - Dual Azimuth Format for Information Interchange -ISO/IEC 12246 Helical Scan RecordingECMA-247 (1996) 8 mm Wide Magnetic Tape Cartridges for Information Interchange - Helical Scan Recording -ISO/IEC 15718 HH-1 FormatECMA-249 (1996) 8 mm Wide Magnetic Tape Cartridge for Info
6、rmation Interchange - Helical Scan RecordingISO/IEC 15757 - DA-2 FormatThe present ECMA Standard specifies a cartridge in the case of which a memory chip can be built. The case hascorresponding specific features. Thus, it is different from that of Standards ECMA-247 and ECMA-249.This ECMA Standard,
7、together with Standards ECMA-247 and ECMA-249 has been contributed to ISO/IEC andadopted as ECMA Standards under the fast-track procedure.This Standard has been adopted as 2ndEdition of Standard ECMA-246 by the ECMA General Assembly of June1998.- i -Table of contentsSection 1 - General 11 Scope 12 C
8、onformance 12.1 Magnetic tape cartridge 12.2 Generating drive 12.3 Receiving drive 13 References 24 Definitions 24.1 Absolute Frame Number (AFN) 24.2 a.c. erase 24.3 Access 24.4 algorithm 24.5 Area ID 24.6 Automatic Track Finding (ATF) 24.7 Average Signal Amplitude 24.8 azimuth 24.9 back surface 24.
9、10 byte 24.11 cartridge 24.12 Channel bit 24.13 Codeword 24.14 Early Warning Point (EWP) 34.15 End of Data (EOD) 34.16 Entity 34.17 Error Correcting Code (ECC) 34.18 flux transition position 34.19 flux transition spacing 34.20 Frame 34.21 Housekeeping Frame 34.22 Logical Beginning of Tape (LBOT) 34.
10、23 magnetic tape 34.24 Master Standard Amplitude Calibration Tape 34.25 Master Standard Reference Tape 34.26 Memory In Cartridge (MIC) 34.27 Partition Boundary 34.28 Physical Beginning of Tape (PBOT) 34.29 Physical End of Tape (PEOT) 44.30 physical recording density 44.31 pre-recording condition 44.
11、32 processing 44.33 processed data 44.34 Processed Record 44.35 record 44.36 Reference Field 44.37 reprocessing 44.38 Secondary Standard Amplitude Calibration Tape 44.39 Secondary Standard Reference Tape 44.40 Separator Mark 44.41 Standard Reference Amplitude (SRA) 4- ii -4.42 Tape Reference Edge 54
12、.43 Typical Field 54.44 Standard Reference Current 54.45 Test Recording Current 54.46 track 54.47 unprocessed data 54.48 Unprocessed Record 55 Conventions and Notations 55.1 Representation of numbers 55.2 Names 56 Acronyms 57 Environment and safety 67.1 Test environment 67.2 Operating environment 67
13、.3 Storage environment 67.4 Transportation 67.5 Safety 67.6 Flammability 6Section 2 - Requirements for the case 78 Dimensional and mechanical characteristics of the case 78.1 General 78.2 Overall dimension 78.3 Holding areas 88.4 Cartridge insertion 88.5 Window 98.6 Loading grips 98.7 Label areas 98
14、.8 Datum areas and Datum holes 98.9 Support areas 108.10 Recognition holes 118.11 Write-inhibit hole 118.12 Pre-positioning surfaces 128.13 Cartridge lid 128.14 Cartridge reel lock 138.15 Reel access holes 148.16 Interface between the reels and the drive spindles 148.17 Light path 158.18 Position of
15、 the tape in the case 168.19 Tape path zone 168.20 Tape access cavity 178.21 Tape access cavity clearance requirements 178.22 Requirements for the MIC 178.22.1 Access holes 178.22.2 Recognition recesses 18Section 3 - Requirements for the unrecorded tape 389 Mechanical, physical and dimensional chara
16、cteristics of the tape 389.1 Materials 38- iii -9.2 Tape length 389.2.1 Length of magnetic tape 389.2.2 Length of leader and trailer tapes 389.2.3 Length of the splicing tapes 389.3 Tape width 389.3.1 Width of magnetic, leader and trailer tapes 389.3.2 Width and position of the splicing tape 389.4 D
17、iscontinuities 389.5 Tape thickness 399.5.1 Thickness of the magnetic tape 399.5.2 Thickness of leader and trailer tape 399.5.3 Thickness of splicing tape 399.6 Longitudinal curvature 399.7 Cupping 399.8 Coating adhesion 399.9 Layer-to-layer adhesion 409.10 Tensile strength 409.10.1 Breaking strengt
18、h 409.10.2 Yield strength 409.11 Residual elongation 409.12 Electrical resistance of the recording surface 419.13 Tape winding 419.14 Light transmittance of the tape 4110 Magnetic recording characteristics 4110.1 Typical Field 4210.2 Signal Amplitude 4210.3 Resolution 4210.4 Overwrite 4210.5 Ease of
19、 erasure 4310.6 Tape quality 4310.6.1 Missing pulses 4310.6.2 Missing pulse zone 4310.7 Signal-to-Noise Ratio (SNR) characteristic 43Section 4 - Requirements for an interchanged tape 4311 Format 4311.1 General 4311.2 Basic Groups 4411.2.1 Entity 4511.2.2 Group Information Table 4511.2.3 Block Access
20、 Table (BAT) 4711.3 Sub-Groups 5011.3.1 G1 Sub-Group 5011.3.2 G2 Sub-Group - Randomizing 5111.3.3 G3 Sub-Group 5211.4 Data Block 5311.4.1 ID information 5411.4.2 Recording of the ID Information in the Data Block Headers 5612 Method of recording 59- iv -12.1 Physical recording density 5912.2 Long-ter
21、m average bit cell length 5912.3 Short-term average bit cell length 5912.4 Rate of change 5912.5 Bit shift 5912.6 Read signal amplitude 5912.7 Maximum recorded levels 5913 Track geometry 6013.1 Track configuration 6013.2 Average track pitch 6013.3 Variations of the track pitch 6013.4 Track width 601
22、3.5 Track angle 6113.6 Track edge straightness 6113.7 Track length 6113.8 Azimuth angles 6114 Recorded patterns 6114.1 Recorded Data Block 6114.2 Margin blocks 6115 Format of a track 6115.1 Track capacity 6115.2 Positioning accuracy 6215.3 Tracking scheme 6316 Layout of a Single Data Space tape 6316
23、.1 Device Area 6416.2 Reference Area 6416.3 Position Tolerance Band No. 1 6416.4 System Area 6516.4.1 System Preamble 6516.4.2 System Log 6516.4.3 System Postamble 6816.4.4 Position Tolerance Band No. 2 6816.4.5 Vendor Group Preamble 6816.5 Data Area 6816.5.1 Vendor Group 6816.5.2 Recorded Data Grou
24、p 6916.5.3 ECC3 6916.5.4 Multiple Recorded Instances 7016.5.5 Repeated Frames 7016.5.6 Appending and overwriting 7016.6 EOD Area 7216.7 Optional Device Area 7216.8 Early Warning Point - EWP 7316.9 Initialization 7317 Layout of partitioned tape 7417.1 Overall magnetic tape layout 7417.1.1 Partition 7
25、417.2 LBOT 75- v -17.3 Empty Partition 7517.4 Initialization of partitioned tapes 7518 Housekeeping Frames 7518.1 Amble Frames 7618.2 System Amble Frames 76Annex A - Measurement of light transmittance 77Annex B - Measurement of Signal-to-Noise Ratio 81Annex C - Method for determining the nominal and
26、 the maximum allowable recorded levels 83Annex D - Representation of 8-bit bytes by 10-bit patterns 85Annex E - Measurement of bit shift 97Annex F - Method of measuring the straightness of track edges 99Annex G - ECC calculation 101Annex H - Recommendations for transportation 105Annex J - Read-After
27、-Write 107Annex K - Example of the content of a Basic Group No. 0 109- vi -.Section 1 - General1ScopeThis ECMA Standard specifies the physical and magnetic characteristics of an 8 mm wide magnetic tapecartridge to enable physical interchange of such cartridges between drives. It also specifies the q
28、uality of therecorded signals, the recording method and the recorded format - called Advanced Intelligent Tape No. 1(AIT-1) - thereby allowing data interchange between drives by means of such magnetic tape cartridges.Information interchange between systems also requires, at a minimum, agreement betw
29、een the interchangeparties upon the interchange code(s) and the specifications of the structure and labelling of the informationon the interchanged cartridge.2 Conformance2.1 Magnetic tape cartridgeA tape cartridge shall be in conformance with this ECMA Standard if it meets all the mandatoryrequirem
30、ents specified herein. The tape requirements shall be satisfied throughout the extent of the tape.2.2 Generating driveA drive generating a magnetic tape cartridge for interchange shall be in conformance with this ECMAStandard if all recordings on the tape meet the mandatory requirements of this ECMA
31、 Standard, and ifeither or both methods of appending and overwriting are implemented.A claim of conformance shall state which of the following optional features are implemented and whichare notG01 the performing of a Read-After-Write check and the recording of any necessary repeated frames;G01 the g
32、eneration of ECC3 Frames.In addition a claim of conformance shall stateG01 whether or not one, or more, registered algorithm(s) are implemented within the system and are able tocompress data received from the host prior to collecting the data into Basic Groups, andG01 the registered identification n
33、umber(s) of the implemented compression algorithm(s).2.3 Receiving driveA drive receiving a magnetic tape cartridge for interchange shall be in conformance with this ECMAStandard if it is able to handle any recording made on the tape according to this ECMA Standard. Inparticular it shallG01 be able
34、to recognise repeated frames, and to make available to the host, data and Separator Marks fromonly one of these frames;G01 be able to recognise multiple representations of the same Basic Group, and to make available to thehost, data and Separator Marks from only one of these representations;G01 be a
35、ble to recognise an ECC3 frame, and ignore it if the system is not capable of using ECC3 checkbytes in a process of error correction;G01 be able to recognise processed data within an Entity, identify the algorithm used, and make itsregistered identification number available to the host;G01 be able t
36、o make processed data available to the host.In addition a claim of conformance shall stateG01 whether or not the system is capable of using ECC3 check bytes in a process of error correction;G01 whether or not one or more de-compression algorithm(s) are implemented within the system, and areable to b
37、e applied to compressed data prior to making such data available to the host;- 2 -G01 the registered identification number(s) of the compression algorithm(s) for which a complementary de-compression algorithm is implemented.3 ReferencesECMA-129 (1994) Information Technology Equipment - SafetyISO/R 5
38、27:1966 Plastics - Determination of tensile properties.ISO 1302:1992 Technical Drawings - Method of indicating surface texture on drawings.ISO/IEC 11576:1994 Information Technology - Procedure for the registration of algorithms for thelossless compression of data.4 DefinitionsFor the purposes of thi
39、s ECMA Standard the following definitions apply.4.1 Absolute Frame Number (AFN)A sequence number, encoded in the Frame.4.2 a.c. eraseA process of erasure utilizing magnetic fields of decaying intensity.4.3 AccessA read or write pass over a partition.4.4 algorithmA set of rules for transforming the l
40、ogical representation of data.4.5 Area IDAn identifier defining the area of the tape and specifying the types of Frame written.4.6 Automatic Track Finding (ATF)The method by which tracking is achieved.4.7 Average Signal AmplitudeThe average peak-to-peak value of the output signal from the read head
41、at the fundamental frequency ofthe specified physical recording density over a minimum of 20,0 mm of track, exclusive of missing pulses.4.8 azimuthThe angular deviation made by the mean flux transition line with a line normal to the centreline of therecorded track.4.9 back surfaceThe surface of the
42、tape opposite to the magnetic coating which is used to record data.4.10 byteAn ordered set of bits acted upon as a unit.4.11 cartridgeA case containing magnetic tape stored on twin hubs.4.12 Channel bitA bit after 8-10 transformation.4.13 CodewordA word generated by a compression algorithm. The numb
43、er of bits in a Codeword is variable, and is notspecified by this ECMA Standard.- 3 -4.14 Early Warning Point (EWP)A point along the length of the tape at which warning is given of the approach, in the forward direction oftape motion, of the Partition Boundary or of the Physical End of Tape.4.15 End
44、 of Data (EOD)The point on the tape at the end of the group which contains the last user data.4.16 EntityA unit of recorded data, comprising an Entity Header and a Record sequence.4.17 Error Correcting Code (ECC)A mathematical computation yielding check bytes used for the detection and correction of
45、 errors.4.18 flux transition positionThat point which exhibits maximum free-space flux density normal to the tape surface.4.19 flux transition spacingThe distance along a track between successive flux transitions.4.20 FrameA pair of adjacent tracks with azimuths of opposite polarity, in which the tr
46、ack with the positive azimuthprecedes that with the negative azimuth.4.21 Housekeeping FrameA Frame which contains no user data and which is identified as such by the setting of the Data Fieldstherein.4.22 Logical Beginning of Tape (LBOT)The point along the length of the tape where a recording of da
47、ta for interchange commences.4.23 magnetic tapeA tape which will accept and retain the magnetic signals intended for input, output and storage purposeson computers and associated equipment.4.24 Master Standard Amplitude Calibration TapeA pre-recorded tape on which the standard signal amplitudes have
48、 been recorded in the tracks of positiveand negative azimuth, 35,0 G03m wide, recorded at a track pitch of 11,0 G03m, on an a.c. erased tape.Note 1The tape includes recording at 1 428,6 ftpmm, 1 904,8 ftpmm, 2 857,1 ftpmm and 3 809,5 ftpmm.Note 2The Master Standard Amplitude Calibration Tape has bee
49、n established by Sony Corporation of Japan.4.25 Master Standard Reference TapeA tape selected as the standard for the Reference Recording Field, Signal Amplitude, Resolution,Overwrite and Signal-to-Noise ratio.NoteThe Master Standard Reference Tape has been established by Sony Corporation of Japan.4.26 Memory In Cartridge (MIC)A chip within the case containing information on recordings made on the tape.4.27 Partition BoundaryThe point along the length of a magnetic tape at which a Partition ends and the next Partition commences.4.28 Physical Beginning of Tape (PBOT)The point where the l
