ANSI INCITS 242-1994 Information Systems - Magnetic Tape Cartridge for Information Interchange - 0.50 in (12.65 mm) Serial Serpentine 48-Track 42 500 bpi (1 673 bpmm) DLT1 Format.pdf

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1、ANSI INCITS 242-1994 (R1999)(formerly ANSI X3.242-1994 (R1999)for Information Systems Magnetic Tape Cartridge forInformation Interchange 0.50 in (12.65 mm), Serial Serpentine,48-Track, 42 500 bpi (1 673 bpmm)ANSI X3.242-l 994 American National Standard for Information Systems Magnetic Tape Cartridge

2、 for Information Interchange - 0.50 in (12.65 mm), Serial Serpentine, 4 their existencedoes not in any respect preclude anyone, whether he has approved the standardsor not, from manufacturing, marketing, purchasing, or using products, processes,or procedures not conforming to the standards.The Ameri

3、can National Standards Institute does not develop standards and will inno circumstances give an interpretation of any American National Standard.Moreover, no person shall have the right or authority to issue an interpretation ofan American National Standard in the name of the American National Stand

4、ardsInstitute. Requests for interpretations should be addressed to the secretariat orsponsor whose name appears on the title page of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute requir

5、e that action be taken periodically to reaffirm, revise, or withdrawthis standard. Purchasers of American National Standards may receive currentinformation on all standards by calling or writing the American National StandardsInstitute.CAUTION: The developers of this standard have requested that hol

6、ders of patents that may be required for theimplementation of the standard disclose such patents to the publisher. However, neither the developers nor the publisherhave undertaken a patent search in order to identify which, if any, patents may apply to this standard. As of the date ofpublication of

7、this standard and following calls for the identification of patents that may be required for the implementationof the standard, no such claims have been made. No further patent search is conducted by the developer or publisher inrespect to any standard it processes. No representation is made or impl

8、ied that licenses are not required to avoidinfringement in the use of this standard.Published byAmerican National Standards Institute11 West 42nd Street, New York, New York 10036Copyright 1994 by Information Technology Industry Council (ITI)All rights reserved.No part of this publication may be repr

9、oduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaContents Page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Introduction .l Normative references .2 Definitions .2 Environment and safety .4 4.1 Cartridge and tape testing environment .4 4.2 Cartridge operating environment .4 4.3 Cartridge storage enviro

11、nment .4 4.4 Transportation . .5 4.5 Safety .5 Tape mechanical, electrical, and magnetic requirements .5 5.1 Material . .5 5.2 Width . .5 5.3 Total thickness . .5 5.4 Base material thickness .5 5.5 Magnetic coating thickness . .5 5.6 Discontinuity . .5 5.7 Longitudinal curvature .5 5.8 Out-of-plane

12、distortions 5 5.9 Cupping .6 5.10 Coating surface roughness . .6 5.11 Coating adhesion . .6 5.12 Layer-to-layer adhesion .6 5.13 Youngs modulus .7 5.14 Flexural rigidity .7 5.15 Electrical resistance of the recording surface . .7 5.16 Electrical resistance of the back surface . .7 5.17 Pre-record co

13、ndition . . .8 5.18 Inhibitor tape .8 5.19 Abrasivity . . . .9 5.20 Tape and leader opacity . .l 1 5.21 Tensile yield force . 11 5.22 Friction coefficient .12 5.23 Coercivity . 12 Tape magnetic-recording performance .12 6.1 Typical field . .12 6.2 Signal amplitude .13 6.3 Resolution . .13 6.4 Overwr

14、ite .13 6.5 Peak shift . .13 6.6 Self erasure . .13 Tape quality . .13 7.1 Dropouts .13 7.2 Excessive duration error 14 7.3 Tape edge quality . .14 7.4 Durability . .14 Mechanical specifications of the tape cartridge .14 8.1 Cartridge case label areas .15 8.2 Cartridge positioning planes .16 i .-_ _

15、-._ _,.- _ _ _ _l-_-. -_- _-_. - - -._ - _._ _ _. -IL-?- -_ _- _-i 1-. _ -e.- paw 8.3 Tape cartridge case material . .16 8.4 File-protect mechanism .16 8.5 Reel lock mechanism. 16 8.6 Tape winding . .16 8.7 Winding tension . .16 8.8 Tape-reel diameter . .16 8.9 Tape-reel moment of inertia .16 8.10 L

16、eader attachment . .27 8.11 Cartridge leader position .27 8.12 Leader retract velocity .27 8.13 Tape exit angles . .27 8.14 Tape access door . .27 8.15 Tape position holes . 27 9 Recording . .27 9.1 Physical recording density .28 9.2 Bit-cell length 28 9.3 Flux transition spacing (peak shift). . .28

17、 9.4 Read signal amplitude .32 9.5 Azimuth 3 2 9.6 Channel skew 3 2 10 Tape format 3 2 10.1 Reference edge of tape .32 10.2 Direction of recording .32 10.3 Tape layout 3 2 10.4 Calibration/directory area . 3 2 10.5 Data area . .35 11 Format of data .38 11.1 General . . .38 11.2 Data bytes . .38 11.3

18、 Physical blocks . . 38 11.4 Logical blocks . .40 11.5 Entities . . . . .40 12 Format and content of block structures .40 12.1 Preamble . .40 12.2 Sync .40 12.3 Data field . .40 12.4 Control field 1 . .41 12.5 Control field 2 . .42 12.6 Cyclical redundancy check (CRC) . .43 12.7 Postamble .44 12.8 U

19、se of logical blocks .44 13 Entity . .47 14 Error handling .47 Tables 1 Dimensions (customary and SI) for figures . .17 2 Identification of tracks . .36 3 Control field 1 configurations . .42 4 Control field 2 configurations 43 ii Figures 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 2

20、4 25 Tape resistance measurement electrodes .8 Tape resistance measurement circuit .9 Alfesil wear bar . .lO Wear bar holding fixture .10 Typical wear pattern .11 Waveform of peakshift . 14 Drawing coordinate system . .15 Tape cartridge .22 Cartridge - bottom view 23 Reel locks and notches . .24 Car

21、tridge - operating position . . . 25 Cartridge - cross section .26 Cartridge - side view . .27 Cartridge reel assembly . .28 Cartridge leader . . . .29 Position of cartridge leader . . . . 30 Tape/leader exit angles . . . 3 1 Recorded patterns of flux transitions. . . . 32 Flux transition spacing de

22、viation . . . .32 Format of calibration area . . . .33 Calibration track position .34 Format of data area . 3 9 Block format . 4 1 ECC blocks. . . . . . . . .45 Entity format . . 47 Annexes A Pre-record condition and magnetic moment measure”ment . . . . . . . . . . . . . . . . 48 B Recommendations f

23、or transportation . _ 49 C Tape cartridge handling guidelines .50 D Recommendation on tape durability . .51 . . . III Foreword (This foreword is not part of American National Standard X3.242-1 994.) This standard presents the minimum requirements for the organization and location of magnetically enc

24、oded data on a 0.50 inch (12.65 mm) wide mag- netic tape cartridge to allow parties that comply with these requirements to interchange information reliably. The standard applies to 48-track, 42 500 bpi (1673 bpmm), serial serpentine modified frequency modulation using tape drives that operate in the

25、 streaming mode. The advantage of using the format described in this standard is that it pro- vides for more than eight times the data capacity when compared to ANSI X3.1 81- 1990, American National Standard for Recorded magnetic tape and cartridge for information interchange, l/2 in (12.65 mm), ser

26、ial serpentine, 22-track, 6667 bpi (262 bpmm) and #8-track, 10 000 bpi (394 bpmm), MFM-encoded - Requirements for recording. The impetus to develop this standard was the requirement for higher capacity tape drives to provide backup for the increasingly greater capaci- ties of the fixed media disk dr

27、ives being used with information processing systems. This standard was developed by Technical Committee X3B5 on Digital Magnetic Tape. This group consists of experienced and qualified special- ists on the recording of digital information on magnetic tape. In the devel- opment of this standard, caref

28、ul consideration was given to current prac- tices, existing equipment and supplies, achieving the broadest possible acceptance, and providing a basis for future improvement in the use of the medium. This standard contains four annexes. Annex A is part of this standard and is normative. Annexes B, C,

29、 and D are informative and are not considered part of this standard. Suggestions for improvement of this standard will be welcome. They should be sent to the Computer and Business Equipment Manufacturers Association, 1250 Eye Street, NW, Suite 200, Washington, DC 20005- 3922. This standard was proce

30、ssed and approved for submittal to ANSI by the Accredited Standards Committee on Information Processing Systems, X3. Committee approval of this standard does not necessarily imply that all committee members voted for its approval. At the time, it approved this standard, the X3 committee had the foll

31、owing members: James D. Converse, Chair Donald C. Loughry, Vice-Chair Joanne Flanagan, Secretary Organization Represented Name of Representative American Nuclear Society , . . . . . . . . . . . . . . . . . . . . . Geraldine C. Main Sally Hartzell (Alt.) AMP, Inc. . . . . . . . . . . . . . . . . . .

32、. . . . . . . . . . . . . . . . . . . . . . . . . . . . Edward Kelly Charles Brill (Alt.) Apple Computer, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Karen Higginbottom David K. Michael (Alt.) AT - relative humidity: 40% to 60% Conditioning before testi

33、ng: Cartridge shall be exposed to the testing envi- ronment for 24 hours. 4.2 Cartridge operating environment Cartridges used for data interchange shall be capable of operating under the following con- ditions. - ambient temperature: 50” F to 104” F (10”cto40c); - relative humidity: 20% to 80%; - ma

34、ximum wet bulb temperature: 78” F (25” C). If during storage or transportation a cartridge has been exposed to conditions outside the above values, it shall be conditioned before use by exposure to the operating environment for a time equal to or greater than the time away from the operating environ

35、ment. Conditioning times in excess of 24 hours are not required. 4.3 Cartridge storage environment Cartridges shall be conditions: - temperature: stored under the following 60” F to 90” F (16”Cto32C); - relative humidity: 20% to 80%; - maximum wet bulb temperature: 80” F (26” C). Tapes containing ar

36、chival data that will stored over a long period of time should stored at this recommended environment: be be - temperature: 65” F to 79” F (18.3” to 26.1 C); - relative humidity: 20% to 60%; - stray magnetic fields at any point on the cartridge shall not exceed 4000 A/M. 4.4 Transportation The total

37、 thickness of the tape for transporta- tion appears in annex D. 4.5 Safety 4.51 Safeness The components of the tape and cartridge assembly shall not constitute any safety or health hazard when used in the intended man- ner, or through any foreseeable misuse in an information processing system. 4.5.2

38、 Flammability The materials used in the external cartridge covers shall have a flammability rating of at least 94V-2, as described in UL94. 5 Tape mechanical, electrical, and mag- netic requirements 5.1 Material The tape shall consist of a base material (ori- ented polyethylene terephthalate film or

39、 its equivalent) coated on one surface with a strong yet flexible layer of ferromagnetic mate- rial dispersed in a suitable binder. The other surface of the base material shall be coated with a nonmagnetic conductive coating. 5.2 Width The width of the tape shall be 0.4980 in +_ 0.0004 in (12.649 mm

40、 + 0.010 mm). The width shall be measured across the tape from edge to edge when the tape is under a tension of less than 1 .O ozf (0.28 N). 5.3 Total thickness The total thickness of the tape at any point shall be between 473 pin (12 pm) and 552 uin (14 v). ANSI X3.242-1994 5.4 Base material thickn

41、ess The thickness of the base material shall be between 366 pin (9.3 urn) and 394 uin (10.0 urn). The design shall meet the total thickness (see 5.3). 5.5 Magnetic coating thickness The magnetic coating thickness shall be between 94.6 pin (2.4 urn) and 130 pin (3.3 pm). The design shall meet the tot

42、al thickness (see 5.3). 5.6 Discontinuity There shall be no discontinuities in the tape between the BOT and EOT markers such as those produced by tape splicing or perfora- tions. 5.7 Longitudinal curvature Longitudinal curvature is the departure of the reference edge of the tape from a straight line

43、 along the longitudinal dimension of the tape in the plane of the tape surface. 5.7.1 Requirement Any deviation of the reference edge from a straight line must be gradual and shall not exceed 0.0015 in (0.038 mm) within any 9.0 in (229 mm) length of tape. 5.7.2 Procedure Measure at a tension of 5.0

44、ozf f 1 .O ozf (1.39 N + 0.28 N) in a test fixture equipped with two guides spaced at 9.0 in (229 mm). The two guides shall be spring loaded to position the reference edge of the tape against two edge control surfaces. Measure the maximum devi- ation of the reference edge of the tape from the line d

45、rawn between the two control sur- faces. 5.8 Out-of-plane distortions Out-of-plane distortions are local deforma- tions that cause portions of the tape to devi- ate from the plane of the surface of the tape. Out-of-plane distortions are most readily observed when the tape is lying on a flat sur- fac

46、e under no tension. All visual evidence of out-of-plane distortion shall be removed when the tape is subjected to a uniform tension of 2.0 ozf (0.6 N). 5 ANSI X3.242-l 994 5.9 Cupping Cupping is the departure across a tape (trans- verse to motion) from a flat surface. 59.1 Requirement The departure

47、across the width of tape from a fiat surface shall be less than 0.030 in (0.76 mm). 5.9.2 Procedure Cut a 36 in (0.9 m) sample of tape. Condition it for a minimum of three hours in the test envi- ronment by hanging it so that the recording sur- face is freely exposed to the test environment. From th

48、e center portion of the acclimated tape cut a sample 1 .O in (25.4 mm) in length. Stand the cut sample on its end in a cylinder, that is at least 1.0 in (25.4 mm) high and has an inside diameter of 0.512 in + 0.008 in (13.0 mm + 0.2 mm). With the cylinder standing on an optical comparator measure th

49、e cupping by aligning the edges of the sample to the reticle and determining the distance from the aligned edges to the corresponding surface of the sample at its center. 5.10 Coating surface roughness 5.10.1 Back coating surface roughness The back coating surface shall have an arith- metic average roughness (Ra) between 0.2 uin (0.005 urn) and 1.0 pin (0.025 urn). For this measurement, the contacting stylus radius shall be 500 pin (12.7 urn) with a 0.71 ozf (20 mg) load, and a 0.010 in (254 urn) cut- off range. 5.10.2 Magnetic coating surface roughness The