SIST EN 28378-3:1997

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7958 ftprad, 3,8 tpmm (96 tpi), on both sides - Part 3: Track format B (ISO 8378-3:1986)Informationsverarbeitung - Datenaustausch auf 130 mm (5.25 in) Disketten mittels modifizierter Frequenzmodulationsaufzeichnung bei 7958 ftprad, 3,8 tpmm (96 tpi), auf beiden Seiten - Teil 3: Spurformat B (ISO 8378-3:1986, Ausg. 1)Traitement de l'information - Echange de données sur cartouches a disquette de 130 mm (5,25 in) utilisant un enregistrement a modulation de fréquence modifiée a 7958 ftprad, 3,8 tpmm (96 tpi), sur deux faces - Partie 3: Schéma de piste B (ISO 8378-3:1986, éd. 1)Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7958 ftprad, 3,8 tpmm (96 tpi), on both sides - Part 3: Track format B (ISO 8378-3:1986, ed. 1)35.220.21Magnetni diskiMagnetic disksICS:Ta slovenski standard je istoveten z:EN 28378-3:1989SIST EN 28378-3:1997en01-december-1997SIST EN 28378-3:1997SLOVENSKI
STANDARD



SIST EN 28378-3:1997



SIST EN 28378-3:1997



SIST EN 28378-3:1997



International Standard 837813 INTERNATIONAL ORGANIZATION FOR STANDARDlZATIONWvlEIKAYHAPO~HAR OPrAHM3ALMR f-IO CTAHAAPTbI3A~MM*ORGANISATION INTERNATIONALE DE NORMALlSATlON Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides - Part 3: Track format B Traitemen t de I ‘information - [change de don&es sur cartouches ;i disquette de 130 mm (5,25 in) utilisan t un enregistrement sj modulation de frkquence modifiee ;5 7 958 ftprad, 3,8 tpmm (96 tpi), sur les deux faces - Partie 3: Schema de piste B Second edition - 1986-12-15 U DC 681327.63 Ref. No. IS0 8378/3-1986 (E) Descriptors : data processing, information interchange, data transfer, data recording devices, magnetic disks, flexible disks, track formats, specifications. Price based on 8 pages SIST EN 28378-3:1997



Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 8378/3 was lnforma tion processing systems. prepared by Technical Committee ISO/TC 97, This second edition cancels and replaces the first edition published on 1986-04-15, clauses 0, 3 and 4 of which have been technically revised. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. 0 International Organization for Standardization, 1986 Printed in Switzerland ii SIST EN 28378-3:1997



IS0 8378/3-1986 (El Contents Page 0 Introduction . 1 Scope and field of application . 2 Conformance . 3 References . 4 Trackformat . 4.1 General requirements . 4.2 Track layout after the first formatting for all tracks . 5 Coded representation of data . 5.1 Standards . 5.2 Coding methods . Annexes A EDC implementation . B Procedure and equipment for measuring flux transition spacing. . C Data separators for decoding MFM recording . 1 1 1 1 1 1 3 4 4 4 . . . Ill SIST EN 28378-3:1997



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Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides - Part 3: Track format B 0 Introduction IS0 8378 specifies the characteristics of 130 mm (5.25 in) flexible disk cartridges recorded at 7 958 ftprad, on 80 tracks on each side, using modified frequency modulation (MFM) recording. IS0 8378/l specifies the dimensional, physical, and magnetic characteristics of the cartridge so as to provide physical inter- changeability between data processing systems. IS0 8378/l and IS0 8378/J, together with the labelling scheme specified in IS0 9293, provide for full data interchange between data processing systems. IS0 8378/2 specifies an alternative track format for data inter- change. 1 Scope and field of application This part of IS0 8378 specifies the quality of recorded signals, the track layout, and a track format to be used on 130 mm (5.25 in) flexible disk cartridges intended for data interchange between data processing systems. NOTE - Numeric values in the SI and/or Imperial measurement system in this part of IS0 8378 may have been rounded off and therefore are consistent with, but not exactly equal to, each other. Either system may be used, but the two should be neither intermixed nor reconverted. The original design of this part of IS0 8378 was made using SI units. 2 Conformance A flexible disk cartridge shall be in conformance with IS0 8378 when it meets all the requirements either of parts 1 and 2 or of parts 1 and 3 of IS0 8378. 3 References IS0 646, Information processing - IS0 T-bit coded character set for information interchange. IS0 2022, Information processing - IS0 7-bit and 8-bit coded character sets - Code extension techniques. IS0 4873, Information processing - IS0 8-bit code for infor- mation interchange - Structure and rules for implementation. IS0 8378, Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified fre- quency modulation recording at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides - Part 7 : Dimensional, physical and magnetic characteristics. Part 2: Track format A. IS0 9293, Information processing - Volume and file structure of flexible disk cartridges for information interchange. ’ ) 4 Track format 4.1 General requirements 4.1.1 Mode of recording The mode of recording shall be Modified Frequency Modu- lation (MFM) for which the conditions are a) a flux transition shall be written at the centre of each bit cell containing a ONE; b) a flux transition shall be written at each cell boundary between consecutive bit cells containing ZEROS. Exceptions to this are defined in 4.1.12. ~--_____ 1) At present at the stage of draft. SIST EN 28378-3:1997



IS0 8378/3-1986 (El 4.1.2 Track location tolerance of the recorded flexible disk cartridge The centrelines of the recorded tracks shall be within -t-O,042 5 mm (0.001 7 in) of the nominal positions, over the range of operating environment specified in IS0 8378/l. 4.1.3 Recording offset angle At the instant of writing or reading a magnetic transition, the transition shall have an angle of O” + 18’ with the radius. NOTE - As tracks may be written and overwritten at extremes of the tolerances given in 4.12 and 4.1.3, a band of old information may be left at one edge of the newly written data and would constitute un- wanted noise when reading. It is, therefore, necessary to trim the edges of the tracks by erasure after writing. 4.153 The spacing between the two ONE flux transitions surrounding a ZERO bit cell shall lie between 185 % and 225 % of the short-term average bit cell length. 4.1.6 Average signal amplitude For each side the average signal amplitude on any non- defective track (see IS0 8378/l ) of the interchanged flexible disk cartridge shall be less than 160 % of SRA, f and more than 40 % of SRA,,f. 4.1.7 Byte A byte is a group of eight bit-positions, identified Bl to B8, with B8 the most significant and recorded first. The bit in each position is a ZERO or a ONE. 4.1.4 Density of recording 4.1.8 Sector 4.1.4.1 The nominal density of recording shall be 7 958 ftprad. The nominal bit cell length is 125,7 prad. 4.1.4.2 The long-term average bit cell length shall be the average bit cell length measured over a sector. It shall be within f3,5 % of the nominal bit cell length. 4.1.4.3 The short-term average bit cell length, referred to a particular bit cell, shall be the average of the lengths of the preceding eight bit cells. It shall be within +8 % of the long- term average bit cell length. 4.1.5 Flux transition spacing (see figure 1) The instantaneous spacing between flux transitions may be in- fluenced by the reading and writing process, the bit sequence recorded (pulse crowding effects), and other factors. The locations of the transitions are defined as the locations of the peaks in the signal when reading. Tests should be carried out using a peak-sensing amplifier. 4.1.5.1 The spacing between the flux transitions in a sequence of ONES shall be between 80 % and 120 % of the short-term average bit cell length. 4.1.5.2 The spacing between the flux transition for a ONE and that between two ZEROS preceding or following it shall be between 130 % and 165 % of the short-term average bit cell length. 1 All tracks are divided into 9 sectors of 512 bytes. 4.1.9 Cylinder A pair of tracks, one on each side, having the same track number. 4.1.10 Cylinder number The cylinder number shall be a two-digit number identical with the track number of the trac
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