ANSI INCITS 136-1986 Information Systems - Serial Recorded Magnetic Tape Cartridge for Information Interchange - 4 and 9 Track 0.250 Inch (6.30 mm) 8000 bpi (315 bpmm) Streaming Mo.pdf

1、ANSI INCITS 136-1986 (R2002) (formerly ANSI X3.136-1986 (R1997)for Information Systems Serial Recorded MagneticTape Cartridge for InformationInterchange 4 and 9 Track, 0.250 inch (6.30 mm),8000 bpi (315 bpmm) Streaming Mode,Group Code RecordingAmericanNationalStandardApproval of an American National

2、 Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the judgment of the ANSI Board of StandardsReview, substantial agreement has been reached by directly and mater

3、iallyaffected interests. Substantial agreement means much more than a simplemajority, but not necessarily unanimity. Consensus requires that all views andobjections be considered, and that a concerted effort be made toward theirresolution.The use of American National Standards is completely voluntar

4、y; 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 American National Standards Institute does not develop standards and will

5、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 StandardsInstitute. Requests for interpretations should be addressed to th

6、e 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 require that action be taken periodically to reaffirm, revise, or withdrawt

7、his standard. Purchasers of American National Standards may receive currentinformation on all standards by calling or writing the American National StandardsInstitute.Published byAmerican National Standards Institute11 West 42nd Street, New York, New York 10036Copyright 1986 by Information Technolog

8、y Industry 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 ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaANSI X3.136-1986 American Natio

9、nal Standard for Information Systems - Serial Recorded Magnetic Tape Cartridge for Information Interchange - 4 and 9 Track, 0.250 inch (6.30 mm), 8000 bpi (315 bpmm) Streaming Mode, Group Code Recording Secretariat Computer and Business Equipment Manufacturers Association Approved February 28,1986 A

10、merican National Standards Institute, Inc American National Standard Approval of an American National Standard requires verification by ANSI that the re- quirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in

11、 the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Sub- stantial agreement means much more than a simple majority, but not necessarily unanim- ity. Consensus requires that all views and objections be considered,

12、and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary, their existence does not in any respect preclude anyone, whether he has approved the standards or not, from man- ufacturing, marketing, purchasing. or using products, processe

13、s, or procedures not con- forming to the standards. The American National Standards Institute does not develop standards and will in no cir- cumstances give an interpretation of any American National Standard. Moreover, no per- son shall have the right or authority to issue an interpretation of an A

14、merican National Standard in the name of the American National Standards Institute. Requests for inter- pretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at a

15、ny time. The procedures of the American National Standards Institute require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of approval. Purchasers of American National Standards may receive current infor- mation on all standards by calling

16、 or writing the American National Standards Institute. Published by American National Standards Institute 1430 Broadway, New York, New York 10018 Copyright 0 1986 by American National Standards Institute, Inc All rights reserved. No part of this publication may be reproduced in any form, in an elect

17、ronic retrieval system or otherwise, without the prior written permission of the publisher Printed in the United States of America AlM686/7 Foreword (This Foreword is not part of American National Standard X3.136-1986.) This standard presents the minimum requirements for the organization and locatio

18、n of magnetically encoded data on a 0.250-inch (6.30-mm)-wide magnetic tape to allow parties that comply with these requirements to reliably interchange information. The standard applies to 4- and 9-track, 8000-bpi (315-bpmm), serial, group-coded information using tape drives that operate in the str

19、eaming mode. The advantage of using the format described in this standard is that it provides far greater data capacities and higher data transfer rates than are provided by the existing formats. For example, the 9-track format allows 45 megabytes of formatted data to be recorded on a cartridge meet

20、ing the requirements of American National Standard for Information Processing - Unrecorded Magnetic Tape Cartridge for Information Interchange, 0.250 inch (6.30 mm), 1600 bpi (63 bpmm), phase encoded, ANSI X3.55-1982, while previous stop/start formats allowed a maximum of 18 megabytes. This standard

21、 was developed by Technical Committee X3B5 on Digital Magnetic Tape. This group consists of experienced and qualified specialists on the recording of digital information on magnetic tape. In the development of this standard, careful consideration was given to current practices, existing equipment an

22、d supplies, achieving the broadest possible acceptance, and providing a basis for a future improvement in the use of the medium. The impetus to develop this standard was the sudden increase in requirements for tape backup systems in the early 1980s. The demand was fueled by the great increase in the

23、 use of small, inexpensive, fixed media rigid disk drives for computer systems. The indus- try provided defacto standard products that were to become the basis for the cartridges described in this American National Standard. Suggestions for improvement of this standard will be welcome. They should b

24、e sent to the Computer and Business Equipment Manufacturers Association, 311 First Street, NW, Washington, DC 200 11. This standard was processed and approved for submittal to ANSI by the Accredited Stan- dards Committee on Information Processing Systems, X3. Committee approval of this standard does

25、 not necessarily imply that all committee members voted for its approval. At the time it approved this standard, the X3 Committee had the following members Edward Lohse, Chair Richard Gibson, Vice-Chair Catherine A. Kachurik, Administrative Secretary Organization Represented American Express. . . .

26、. . . . . . . . . . . . . . American Library Association. . . . . . . . . . American Nuclear Society . . . . . . . . . . . . . AMP Incorporated . . . . . . . . . . . . . Association for Computing Machinery . Association of the Institute for Certification of Computer Professionals AT P = Preamble; D

27、= Data or control block. Dimension Minimum (inch) (mm) Maximum (inch) (mm) Description aI 0 0 0 0 BOT to start of track reference burst 3.0 16.2 4.0 101.6 Load point to end of track reference burst and start of preamble on even tracks a3 - - 36.0 914.4 Early warning to end of data on even tracks a4

28、1.0 25.4 2.0 50.8 Early warning to start of preamble on odd tracks a, 0.1 2.5 4.0 101.6 End of data to load point on Tracks 1 and 7 a6 - - 27.0 685.8 Load point to end of data on Tracks 3 and 5 Figure 1 Tape Position Holes 9 AMERICAN NATIONAL STANDARD X3.136-1986 BELT GUIDE ROLLERS (2) TAPE SHOWN IN

29、 FLAT DRIVE BELT TAKE-UP HUB BOT POSITION I I SUPPLY HUB , 1 I / BELT CAPSTAN / RUBBER-COVERED DRIVE ROLLER DRIVE MOTOR x I - - FIXED TAPE GUIDES (2) MIRROR LIGHT SENSING LDIRECTION OF FORWARD TAPE MOTION ECT Figure 2 Possible Cartridge Configuration 10 AMERICAN NATIONAL STANDARD X3.136-1986 3.13 Er

30、ase. To remove all magnetically recorded infor- mation from the tape. 3.14 File Mark. An identification mark following the last block in a file. 3.15 Flux Transition. A point on the magnetic tape that exhibits maximum free space flux density normal to the tape surface. 3.16 Flux Transition Spacing.

31、The distance on the magnetic tape between flux transitions. 3.17 Group Code Recording (GCR). A data encoding method in which a 4-bit group of data bits is encoded into a 5-bit group for recording on magnetic tape (see ANSI X3.54-1986 for more information about this type of recording). 3.18 Load Poin

32、t (LP) Marker. A single hole punched in the tape to indicate the approaching start of the usable recording area in the forward direction (see Figure 1). 3.19 Nibble. A group of 4 data (5 encoded) bits oper- ated on as a unit 3.20 Postamble. A special sequence of bits recorded at the end of each reco

33、rded block. 3.21 Preamble. A special sequence of bits recorded at the beginning of recorded block. 3.22 Recorded Block. A group of consecutive bits comprising preamble, data block marker, data block, block address, CRC, and postamble. 3.23 Master Standard Amplitude Reference Tape. An amplitude refer

34、ence tape that has been selected by the National Bureau of Standards (NBS) to establish the reference level for average peak-to-peak signal ampli- tude output when recorded at 10 000 ftpi (394 ftpmm) on a master measurement system. 3.24 Secondary Standard Amplitude Reference Tape. An amplitude refer

35、ence tape that has been calibrated by the NBS with respect to the reference level of the master standard amplitude reference tape.3 3.25 Streaming. A method of recording on magnetic tape that maintains continuous tape motion without the requirement to start and stop within an inter- record gap. 3A m

36、aster standard amplitude reference tape has been estab- lished at the NBS. Secondary standard amplitude reference tapes are available from NBS under part number SRM 3217. For ordering information, contact: Office of Standard Refer- ence Materials, Room B311, Chemistry Building, National Bureau of St

37、andards, Gaithersburg, MD 20899. 3.26 Track. A longitudinal area on the tape along which a series of magnetic signals may be recorded. 3.27 Underrun. A condition that develops when the host transmits or receives data at a rate less than that required by the device for streaming operation. 4. Recordi

38、ng 4.1 Method. The method of recording shall be the “non-return to zero, change on one” (NRZl) where a ONE is represented by a flux transition occurring in the bit cell and a ZERO is represented by the absence of a flux transition in the bit cell. 4.2 Code. Each g-bit data byte is separated into two

39、 4-bit groups (nibbles). Each 4-bit data nibble is en- coded into a 5-bit GCR nibble for recording on the streaming magnetic tape cartridge. The most significant nibble is recorded first The encoded data has the prop- erty that no more than two consecutive ZEROS shall occur. The translation table fo

40、r data nibbles (B3, B2, Bl , BO) and GCR nibbles (G4, G3, G2, Gl , GO) shall be as shown in Table 1 4.2.1 Byte and Code Requirements 4.2.1 .l Byte Length. The data shall be in g-bit bytes. 4.2.1.2 Code. Bits bl through b7 shall corres- pond to the bit assignments for 7-bit ASCII characters as descri

41、bed in ANSI X3.4-1986. Bit bs shall always be ZERO when the seven bits, bi through b7, represent a 7-bit ASCII character. Each of the bits br through bs may be either a ZERO or a ONE when the representation is coded in accordance with a standard, as agreed upon by the interchange parties, which perm

42、its such encoding. 4.3 Density of Recording 4.3.1 Density. The nominal recording density shall be 10 000 ftpi (394 ftpmm). 4.3.2 Bit Cell Length. The nominal bit cell length shall be 100 microinches (2 54 micrometers). 4.3.3 Average Bit Cell Length. The average bit cell length is the sum of distance

43、s over N bit cells divided byN. 4.3.4 Long-Term Average Bit Cell Length. The long-term average bit cell length is the average bit cell length taken over a minimum of 900 000 bit cells. The long-term average bit cell length shall be within f 4% of the nominal bit cell length. 4.3.5 Short-Term Average

44、 Bit Cell Length. The short-term average bit cell length is the average taken over a minimum of 126 and a maximum of 130 bit cells. The short-term average bit cell length shall be within +7% of the long-term average. 11 AMERICAN NATIONAL STANDARD X3.136-1986 Table 1 Translation Table for Data Nibble

45、s and GCR Nibbles HEX B3 B2 Bl BO G4 G3 G2 Gl GO HEX 0 0 0 0 - 1 1 0 1 19 1 0 0 8 1 - 1 1 i 1 1 1B 2 0 0 1 0 - 1 0 0 1 0 12 3 0 0 1 1 - 1 0 0 1 1 13 40100+1 1 1 1D 5 0 1 0 1 t-* 1 i 1 15 6 0110c-t1 1 1 i 16 70111-l 8 1 1 1 17 8 1 0 1 0 9 1 0 il 1 0 A 1 10*0101 B 1 8 1 1 - 0 1 0 1 1 OB C 1100+111 0 1

46、E D 1 1 0 1 - 1 1 ; 1 OD E 1 1 1 0 - 8 1 1 1 0 OE F 1 1 1 1 - 0 1 1 1 1 OF NOTE: GCR bit G4 is recorded first. 4.3.6 Rate of Change of Bit Cell Length. The rate of change of bit cell length shall not exceed 0.26%. The rate of change is given by the following relationship. Rate of change = IfI /4 - h

47、/41 h/5 Where tl, t2, and t3 are the times between flux transi- tions as shown in Figure 3. Periods 1 through 5 are contiguous and represent the reptitive data pattern 101010 within a data block, and frequency variations are less than 20 kHz. 4.3.7 Instantaneous Flux Transition Spacing. The instanta

48、neous spacing between flux transitions is in- fluenced by the reading and writing processes, the pat- tern recorded (pulse-crowding effect) and other factors. Instantaneous spacings between flux transitions shall satisfy the following conditions. In a sequence of flux transitions defined by the bit

49、pattern 11100111 (e.g., as occurs in the block marker as described in 5.2), the center flux transition of each group of ONES is called a reference flux transition. The maximum displacement of flux transitions on either side of the reference flux transitions shall not exceed f 35% of the bit cell length dr averaged over the five bit cells between the reference flux transitions indi- cated in the bit pattern in Figure 4. 4.4 Measurement of Signal Amplitude. The signal in which amplitude shall be measured at a point in the read channel in which the signal is proportional to