1、ANSI INCITS 312-1998 (R2003)(formerly ANSI NCITS 312-1998)for Information Technology Magnetic Tape Cartridgefor Information Interchange,0.50 in (12.65 mm),Serial Serpentine, 128-Track,81 600 bpi (3212 bpmm) DLT4 FormatANSINCITS 312-1998American National Standardfor Information Technology Magnetic Ta
2、pe Cartridgefor Information Interchange,0.50 in (12.65 mm),Serial Serpentine, 128-Track,81 600 bpi (3212 bpmm) DLT4 FormatSecretariatInformation Technology Industry CouncilApproved April 28, 1998American National Standards Institute, Inc.Approval of an American National Standard requires review by A
3、NSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Subs
4、tantial agreement means much more thana simple majority, but not necessarily unanimity. Consensus requires that allviews and objections be considered, and that a concerted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not i
5、n any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not conforming to the standards.The American National Standards Institute does not develop standards andwill in no circumstances give inte
6、rpretation on any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose n
7、ame appears on the titlepage of this standard.CAUTION NOTICE:This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of Ameri
8、can National Standards mayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.11 West 42nd Street, New York, NY 10036Copyright 1998 by Information Technology Indus
9、try Council (ITI)All rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaCAUTION:The developers of this standard have requested that holders o
10、f patents that may be re-quired for the implementation of the standard disclose such patents to the publisher. However, nei-ther the developers nor the publisher have undertaken a patent search in order to identify which, ifany, patents may apply to this standard.As of the date of publication of thi
11、s standard, following calls for the identification of patents thatmay be required for the implementation of the standard, notice of one or more such claims hasbeen received.By publication of this standard, no position is taken with respect to the validity of this claim or ofany rights in connection
12、therewith. The known patent holder(s) has (have), however, filed a state-ment of willingness to grant a license under these rights on reasonable and nondiscriminatoryterms and conditions to applicants desiring to obtain such a license. Details may be obtained fromthe publisher.No further patent sear
13、ch is conducted by the developer or publisher in respect to any standard itprocesses. No representation is made or implied that this is the only license that may be requiredto avoid infringement in the use of this standard.iContentsPageForeword.iv1Introduction. 11.1 Scope . 11.2 Purpose 11.3 Conform
14、ance 21.4 Dimensions. 22Normative references . 23Definitions. 34Environment and safety 54.1 Cartridge and tape testing environment . 54.2 Cartridge operating environment 64.3 Cartridge storage environment. 64.4 Transportation 64.5 Safety . 65Tape mechanical, electrical, and magnetic requirements 75.
15、1 Material. 75.2 Tape Length . 75.3 Total thickness 75.4 Width 75.5 Discontinuity . 75.6 Longitudinal curvature 75.7 Out-of-plane distortions 75.8 Cupping 85.9 Coating surface roughness. 85.10 Coating adhesion 85.11 Layer-to-layer adhesion 95.12 Youngs modulus 105.13 Flexural rigidity . 105.14 Tensi
16、le yield force. 105.15 Electrical resistance of the recording surface. 115.16 Electrical resistance of the back surface 115.17 Inhibitor tape. 125.18 Abrasivity 125.19 Tape and leader opacity. 135.20 Friction coefficient. 135.21 Pre-record condition . 136Tape magnetic recording performance. 146.1 Ty
17、pical field. 146.2 Signal amplitude. 146.3 Resolution. 146.4 Overwrite 146.5 Peak shift 156.6 Self-erasure 157Tape quality 16iiPage7.1 Dropouts. 167.2 Excessive duration error. 167.3 Tape edge quality. 168Mechanical specifications of the tape cartridge 168.1 Cartridge case label areas . 178.2 Cartri
18、dge positioning planes. 178.3 Tape cartridge case material 178.4 File-protect mechanism 178.5 Reel lock mechanism . 188.6 Tape winding 188.7 Winding tension 188.8 Tape-reel diameter . 188.9 Tape-reel moment of inertia . 188.10 Leader attachment . 188.11 Cartridge leader position 188.12 Leader retrac
19、t velocity 188.13 Tape exit angles . 198.14 Tape access door. 198.15 Tape position holes 199Recording . 199.1 Method of recording . 199.2 Code conversion 199.3 Physical recording density 199.4 Bit-cell length 199.5 Read signal amplitude 209.6 Azimuth 209.7 Channel skew. 2010Tape format 2010.1 Refere
20、nce edge of tape 2010.2 Direction of recording . 2010.3 Tape layout. 2010.4 Calibration/directory area . 2110.5 Data area 2311Format of data 2511.1 General. 2511.2 Data bytes 2511.3 Logical blocks. 2512Format and content of block structures 2712.1 Preamble 2712.2 Sync . 2712.3 Data field 2712.4 EDC
21、2812.5 Control field 1 . 2812.6 Control field 2 . 3012.7 Cyclical redundancy check (CRC) 3112.8 Postamble 3112.9 Use of logical blocks. 31iiiPage13Entity. 3314Error handling . 33Tables1RLL code conversion 332Dimensions (customary and SI) for figures. 343Identification of tracks . 394Block format 435
22、Contents of Map Entries . 446Control field 1 configuration 457Control field 2 configuration 46Figures1Tape resistance measurement electrodes 472Tape resistance measurement circuit. 473Waveform of peakshift 484Measurement of abrasivity 495Drawing coordinate system 506Tape cartridge. 507Cartridge - Bo
23、ttom view 518Reel locks and notches 529Cartridge - Operating position. 5310Cartridge - Side view 5411Cartridge - Cross section 5512Cartridge reel assembly 5613Cartridge leader 5714Position of cartridge leader . 5815Tape/leader exit angles 5916Format of calibration area. 6017Calibration track positio
24、n 6118Format of data area 6219ECC blocks . 6320Entity format 65AnnexesAPre-record condition and magnetic moment measurement 66BRecommendations for transportation 67CTape cartridge handling guidelines. 69ivPageDRecommendations on tape durability . 70EBibliography 71vForeword (This foreword is not par
25、t of American National Standard NCITS 312-1998.)This standard presents the minimum requirements for the organization and locationof magnetically encoded data on a 0.50-inch (12.65-mm)-wide magnetic tape car-tridge to allow parties that comply with these requirements to interchange informationreliabl
26、y. The standard applies to 128-track, 81 600 bpi (3 213 bpmm), serial serpen-tine, 2,7 RLL recording mode tape drives that operate in the streaming mode. Thisformat is called DLT4.The advantage of using the format described in this standard is that it provides morethan twice the data capacity when c
27、ompared to the format described in American Na-tional Standard for Information Technology - Magnetic Tape Cartridge for InformationInterchange 0.50 in (12.65 mm), Serial Serpentine, 128-Track, 62 500 bpi (2 460bpmm), DLT3 Format,ANSI X3.282-1996; three times the capacity of the format de-scribed in
28、American National Standard for Information Technology - Magnetic TapeCartridge for Information Interchange 0.50 in (12.65 mm), Serial Serpentine 112-Track, 42 500 bpi (1 673 bpmm) DLT2 Format,ANSI X3.266-1996; and eight timesthe capacity of the format described in American National Standard for Info
29、rmationSystems - Magnetic Tape Cartridge for Information Interchange - 0.50 in (12.65 mm),Serial Serpentine, 48-Track, 42 500 bpi (1 673 bpmm) DLT1 Format,ANSI X3.242-1994.The impetus to develop this standard was the requirement for higher-capacity tapedrives to provide backup for the increasingly g
30、reater capacities of the fixed mediadisk drives being used with information processing systems.This standard was developed by Technical Committee NCITS B5 on Digital MagneticTape. This group consists of experienced and qualified specialists on the recording ofdigital information on magnetic tape. In
31、 the development of this standard, careful con-sideration was given to current practices, existing equipment and supplies, achievingthe broadest possible acceptance, and providing a basis for future improvement inthe use of the medium.This standard contains five annexes. Annex A is part of this stan
32、dard and is norma-tive. Annexes B, C, D and E are informative and are not considered part of this stan-dard.Requests for interpretation, suggestions for improvement or addenda, or defect re-ports are welcome. They should be sent to the National Committee for InformationTechnology Standards (NCITS),
33、ITI, 1250 Eye Street, NW, Suite 200, Washington,DC 20005.This standard was processed and approved for submittal to ANSI by NCITS. Com-mittee approval of this standard does not necessarily imply that all committee mem-bers voted for its approval. At the time it approved this standard, NCITS had thefo
34、llowing members:Karen Higginbottom, Chair(vacant), Vice-ChairMonica Vago, SecretaryOrganization Represented Name of RepresentativeAMP, IncJohn HillCharles Brill (Alt.)Apple Computer, IncDavid K. MichaelJerry Kellenbenz (Alt.)AT maximum wet bulb temperature: 0.15.5.20.2 ProcedureThe following procedu
35、re shall be used for the friction coefficient measurements.For the back-to-front measurement, wrap a tape sample, with a total wrap angle of at least 90 degrees,around a 1-in (25-mm) -diameter cylindrical mandrel (calcium titanate ceramic, Ra = 2 in) with the backsurface of the tape facing outward.
36、Place a second sample of tape with the magnetic coating surface facinginward around the first sample with a total wrap angle of 90 degrees. Attach one end of the outer tape to a0.145 lb (0.066 kg) weight. Attach the other end to a force gauge mounted on a motorized linear slide. Drivethe slide at a
37、speed of 0.04 in/sec (1 mm/sec). Connect the force gauge to a plotter to record the results.Particular attention should be given to keeping the samples clean and secure. The first piece of tape shall notmove during the test.For the measurements of the front and back individual friction, remove the f
38、irst piece of tape.5.21 Pre-record conditionThe tape shall have been anhysteretically erased to ensure that the remanent magnetic moment of therecording surface does not produce an amplitude more than 2% of the average signal amplitude and that nolow density transitions are present on the tape. This
39、 requirement is for testing the tape, and does not need tobe performed for writing data on the tape.NOTE - See annex A for the explanation of the requirement and for a suggested method of measurement.ANSI NCITS 312-1998146 Tape magnetic recording performanceThe magnetic recording performance is defi
40、ned by the testing requirements given in the following paragraphs.When performing the tests, the output or resultant signal shall be measured on the same relative pass forboth the reference tape and the tape under test (read-while-write, or on equipment without read-while-writecapability, on the fir
41、st forward-read-pass) on the same equipment.The following conditions shall apply to all magnetic recording testing requirements, unless otherwise noted: tape condition: pre-record condition; tape speed: 98.0 in/s 2 in/s (2.49 m/s 0.05 m/s); read gap: within the written track; gap alignment: 5 of arc
42、 between the mean write transitions and the read gap; write-gap length: 35 in 7 in (0.89 m 0.18 m); write-gap width: 0.0085 in 0.0004 in (0.216 mm 0.010 mm); read-gap length: 7.00 in 1.80 in (0.18 m 0.05 m); read-gap width: 0.0017 in 0.0002 in (0.043 mm 0.05 mm); tape tension: 2.85 ozf 0.3 ozf (0.79
43、 N 0.08 N); recording current: standard measurement current (It); Bandwidth of read amplifier 10.0 MHz; Physical recording densities:2F = 54 422 ftpi 1088 ftpi (2142 ftpmm 43 ftpmm) corresponding to 2.667 MHz;1F = 27 211 ftpi 545 ftpi (1071 ftpmm 22 ftpmm) corresponding to 1.333 MHz.6.1 Typical fiel
44、dThe typical field of the 2F frequency shall be between 75% and 125% of the master standard reference tapefield. Traceability to the corresponding master standard reference field is provided by the calibration factorssupplied with each secondary standard reference tape.6.2 Signal amplitudeThe averag
45、e signal amplitude of the 2F frequency shall be between 85% and 115% of the correspondingsignal amplitude of the master standard reference tape. Traceability to the corresponding master standardreference signal amplitude is provided by the calibration factors supplied with each secondary standardref
46、erence tape.6.3 ResolutionThe resolution is the ratio of the average signal amplitude at the physical recording density of 54 422 ftpi(2142 ftpmm) to that at the physical recording density of 27 211 ftpi (1071 ftpmm). The resolution shall bebetween 90% and 120% of that for the master standard refere
47、nce tape.Traceability to the corresponding resolution of the master standard reference tape is provided by thecalibration factors supplied with each secondary standard reference tape.6.4 Overwrite6.4.1 RequirementThe overwrite shall be within 3dB or better of master standard reference tape.ANSI NCIT
48、S 312-1998156.4.2 ProcedureThe overwrite is measured using the following procedure:a) Record a 1F pattern at the standard measurement current Im;b) Measure the average signal amplitude of the 1F pattern;c) Record a 2F pattern at the standard measurement current Imover the recorded pattern;d) Measure
49、 the average signal amplitude of the overwritten 1F pattern;e) Calculate the ratio of the overwritten 1F pattern amplitude to the original 1F pattern amplitude.The overwrite (dB) = 20 log(ratio)6.5 Peak shiftPeak shift is measured as the time displacement from nominal of the 1s transitions in the channel bit patternrecorded on tape as 1101101102.6.5.1 RequirementThe measured peak shift percentage shall not differ from that of the master standard reference tape by morethan 2 percentage points.6.5.2 ProcedureThe standard measure
