SIST EN 28378-2:1997

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 2: Track format A (ISO 8378-2:1986)Informationsverarbeitung - Datenaustausch auf 130 mm (5.25 in) Disketten mittels modifizierter Frequenzmodulationsaufzeichnung bei 7958 ftprad, 3,8 tpmm (96 tpi), auf beiden Seiten - Teil 2: Spurformat A (ISO 8378-2:1986, 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 2: Schéma de piste A (ISO 8378-2:1986, 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 2: Track format A (ISO 8378-2:1986, ed. 1)35.220.21Magnetni diskiMagnetic disksICS:Ta slovenski standard je istoveten z:EN 28378-2:1989SIST EN 28378-2:1997en01-december-1997SIST EN 28378-2:1997SLOVENSKI
STANDARD



SIST EN 28378-2:1997



SIST EN 28378-2:1997



SIST EN 28378-2:1997



International Standar 837812 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.ME~~YHAPOJ1HAR OPTAHM3AL&lR t-IO CTAH~APTM3AlJb’lkl.ORGANlSATlON INTERNATIONALE DE NORMALISATION 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 2: Track format A Traitemen t de l’informa tion - i‘change de don&es SW cartouches ;i disquette de 130 mm (5,25 in) utilisant un enregistrement ?I \ modulation de fr&uence modifiee 2 7 958 ftprad, 3,8 tpmm (96 tpi), sur les deux faces - Partie 2: Schema de piste A First edition - 1986-04-45 UDC 681.327.63 Ref. No. IS0 8378/2-1986 (E) Descriptors : data processing, information interchange, data recording devices, magnetic disks, flexible disks, track formats, specifications. Price based on 13 pages SIST EN 28378-2:1997



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 8378/2 was prepared by Technical Committee ISO/TC 97, Information processing systems. 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, 1966 Printed in Switzerland ii SIST EN 28378-2:1997



Contents Page 0 Introduction. . 1 1 Scope and field of application . 1 2 Conformance.‘. 1 3 References . 1 4 Trackformat . 1 4.1 General requirements . 1 4.2 Track layout after the first formatting for track 00, side 0 . 3 4.3 Track layout after the first formatting for all tracks other than track00,sideO. 5 4.4 Track layout of a recorded flexible disk for data interchange . . . . . . . . . . . . 6 Annexes A EDC implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 B Procedure and equipment for measuring flux transition spacing. . . . . . . . . . . . . 10 C Data separators for decoding MFM recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SIST EN 28378-2:1997



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INTERNATIONAL STANDARD IS0 8378/2-1986 (E) 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 2: Track format A 0 Introduction IS0 8378 specifies the characteristics of 130 mm (5.25 in) flexible disk cartridges recorded at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides 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 8378/3 specifies an alternative track format for data inter- change. Together with the labelling scheme specified in IS0 7665, IS0 8378/l and IS0 8378/2 provide for full data interchange between data processing systems. 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 7-bit coded character set for information interchange. IS0 2022, Information processing - /SO 7-bit and 8-bit coded character sets - Code extension techniques. IS0 4873, Information processing - /SO 8-bit code for infor- ma tion interchange - S true ture and rules for implementation. IS0 7665, Information processing - File structure and labelling of flexible disk cartridges for information interchange. IS0 8378, Information processing - Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified fre- quency moduia tion recording at 7 958 ftprad, 3‘8 tpmm (96 tpi), on both sides - Part 7 : Dimensional, physical and magnetic characteristics. Part 3: Track format B. 4 Track format 4.1 General requirements 4.1.1 Mode of recording 4.1.1.1 Track 00, side 0 The mode of recording shall be two-frequency where the start of every bit cell is a clock flux transition. A ONE is represented by a data flux transition between two clock flux transitions. Exceptions to this are defined in 4.1.12. 4.1.1.2 All tracks other than track 00, side 0 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. SIST EN 28378-2:1997



1s0 8378/2-1986 (E) 4.1.2 Track location disk cartridg e tolerance of the recorded flexible The centrelines of the recorded tracks shall be within +0,042 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 4.1.2 and 4.1.3, a band of old information may be left at one edge of the newly written data and would constitute unwanted noise when reading. It is, therefore, necessary to trim the edges of the tracks by erasure after writing. 4.1.4 Density of recording 4.1.4.1 The nominal density of recording shall be 7 958 ftprad. The nominal bit cell length for track 00, side 0 is 251 prad, and for all the other tracks it 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 +3,5 % 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 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. 4.151 Flux transition spacing for track 00, side 0 (see figure I). 4.1.5.1.1 The spacing between two clock flux transitions surrounding a data flux transition or between two data flux transitions surrounding a clock flux transition shall be between 90 % and 140 % of the nominal bit cell length. 4.1.5.1.2 The spacing between two clock flux transitions not surrounding a data flux transition or between two data flux transitions surrounding a missing clock flux transition shall be between 60 % and 110 % of the nominal bit cell length. 4.1.5.1.3 The spacing between a data flux transition and the preceding clock flux transition (when not missing) or between a clock flux transition and the -preceding data flux transition (when not missing) shall be between 45 % and 70 % of the nominal bit cell length. 4.1.5.2 Flux transition spacing for all tracks other than track 00, side 0 (see figure 2). 4.1.5.2.1 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. 4.1.5.2.2 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. 4.1.5.2.3 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 “9/o of SRA,, . Figure 1 2 SIST EN 28378-2:1997



IS0 8378/2-1986 (El i L b 4 800/o to 1200/o O”/o to 165 O/o 185O/o to 225% Figure 2 4.1.7 Byte (4E) for (B8 to Bl) = 01001110 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. (FE) for (B8 to Bl) = 11111110 (FB) for (B8 to Bl) = 11111011 (F8) for (B8 to Bl) = 11111000 4.1.8 Sector (Al)* for (88 to Bl) = 10100001 All tracks are divided into 16 sectors. where the boundary transition between B3 and B4 is missing. 4.1.9 Cylinder 4.1.13 Error detection characters (EDC) A pair of tracks, one on each side, having the same track number. The two EDC-bytes are hardware generated by shifting serially the relevant bits, specified later for each part of the track through a 16-bit shift register described by 4.1.10 Cylinder number The cylinder number shall be a two-digit number identical with the track number of the tracks of the cylinder. xl6 + xl* + x5 + 1 (See also annex A.) 4.1.11 Data capacity of a track The data capacity of track 00, side 0 shall be 2 048 bytes. The data capacity of all tracks other than track 00, side 0 shall be 4 096 bytes. 4.2 Track layout after the first formatting for track 00, side 0 After the first formatting, there shall be 16 usable sectors on the track. The layout of the track shall be as shown in figure 3. 4.1.12 Hexadecimal notation . Hexadecimal notation shall be used hereafter to denote the following bytes : During formatting the rotational speed of the disk, averaged index to index, shall be 300 * 6 r/min. 4.2.1 Index gap (00) for (B8 to Bl) = 00000000 (01) for (B8 to Bl) = 00000001 (FF) for (B8 to Bl) = 11111111 (FE)* for (B8 to Bl) = 11111110 where the clock transitions of B6, B5 and B4 are missing (FB)” for (B8 to Bl) = 11111011 where the clock transitions of B6, B5 and B4 are missing (F8)” for (B8 to 61) = 11111000 where the clock transitions of B6, B5 and B4 are missing At nominal density, this field shall comprise 16 (FF)-bytes. Writing the index gap is started when the index hole is detected. Any of the first 8 bytes may be ill-defined due to subsequent overwriting. 4.2.2 Sector identifier This field shall be as given in table 1. Table 1 Sector identifier Identifier mark Address identifier Track address S EDC c Side 6 bytes 1 byte 1 byte 1 byte 1 byte 1 byte 2 bytes (00) (FE). (00) (00) (00) 3 SIST EN 28378-2:1997



IS0 8378/2-1986 (El INDEX SECTOR GAP IDENTIFIER FIRST DATA IDENTIFIER GAP DATA BLOCK BLOCK GAP A kk 1 st Sector Figure 3 4.2.2.1 Identifier mark This field shall comprise 7 bytes: 6 (OO)-bytes 1 (FE)*-byte 4.2.2.2 Address identifier This field shall comprise 6 bytes. 4.2.2.2.1 Track address This field shall comprise two bytes : a) Cylinder address (C) This field shall specify in binary notation the cylinder address. It shall be (00) for all sectors. b) Side number (Side) This field shall specify the side of the disk. It shall be (00) for all sectors. 4.2.2.2.2 Sector number (S) The 3rd byte shall specify in binary notation the sector number from 01 for the 1st sector to 16 for the last sector. The 16 sectors shall be recorded in the natural order: 1, 2, 3 . . . 15, 16 4.2.2.2.3 4th byte of the sector address The 4th byte shall always be a (OO)-byte. 4.2.2.2.4 EDC These two bytes shall be generated as defined in 4J. 13 using the bytes of the sector identifier starting with the (FE)*-byte (see 4.2.2.1) of the identifier mark and ending with the 4th byte (see 4.2.2.2.3) of the address identifier. 4.2.3 Identifier gap This field shall comprise 11 initially recorded (FF)-bytes. 4 ------- 16th Sector 4.2.4 Data block This field shall be as given in table 2. Table 2 4.2.4.1 Data mark This field shall comprise 6 (00)bytes 1 (FB)*-byte 4.2.4.2 Data field This field shal
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