SIST EN 28860-2:1997

SLOVENSKI STANDARD
SIST EN 28860-2:1997
01-december-1997
Information processing - Data interchange on 90 mm (3.5 in) high density flexible
disk cartridges using modified frequency modulation recording at 7958 ftprad, 5.3
tpmm (135 tpi) on both sides - Part 2: Track format (ISO 8860-2:1987)
Information processing - Data interchange on 90 mm (3.5 in) high density flexible disk
cartridges using modified frequency modulation recording at 7958 ftprad, 5.3 tpmm (135
tpi) on both sides - Part 2: Track format (ISO 8860-2:1987, ed. 1)
Informationsverarbeitung - Datenaustausch auf 90 mm (3.5 in) Disketten unter
Verwendung von modifizierter Wechseltaktschrift mit 7958 Flußwechseln je rad auf 90
Spuren auf jeder Seite - Teil 2: Spurformat (ISO 8860-2:1987, Ausg. 1)
Traitement de l'information - Echange de données sur cartouches a disquette de 90 mm
(3,5 in) utilisant un enregistrement MFM a 7958 ftprad, 5,3 tpmm (135 tpi) sur deux faces
- Partie 2: Schéma de piste (ISO 8860-2:1987, éd. 1)
Ta slovenski standard je istoveten z: EN 28860-2:1989
ICS:
35.220.21 Magnetni diski Magnetic disks
SIST EN 28860-2:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 28860-2:1997

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SIST EN 28860-2:1997

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SIST EN 28860-2:1997

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SIST EN 28860-2:1997
IS0
INTERNATIONAL STANDARD
8860-2
First edition
1987-07-01
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION
ORGANISATION INTERNATIONALE DE NORMALISATION
MEXAYHAPOflHAfl OPrAHM3A~MR IlO CTAH~APTM3A~MM
Information processing -
Data interchange on 90 mm
(3.5 in) flexible disk cartridges using modified
frequency modulation recording at 7 958 ftprad on
80 tracks on each side -
Part 2 :
Track format
Traitemen t de I ‘information - khange de donnt$es SW cartouches A disquette de 90 mm
(3,5 in) utilisant un enregistrement ;i modulation de frhguence modifibe 1MFM) ;i 7 958 ftprad
sur 80 pistes sur chaque face -
Partie 2 : Schdma de piste
Reference number
L
IS0 8860-2 : 1987 (E)

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SIST EN 28860-2:1997
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 prodedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 8860-2 was prepared by Technical Committee ISO/TC 97,
lnforma tion 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, 1987
Printed in Switzerland
ii

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SIST EN 28860-2:1997
IS0 8860-2 :1987 (E)
Contents
Page
1
0 Introduction. .
.......................................... 1
1 Scope and field of application
1
2 Conformance .
1
3 References .
1
4 General requirements .
1
4.1 Modeofrecording .
........ 1
4.2 Track location tolerance of the recorded flexible disk cartridge.
.......................................... 1
4.3 Recording offset angle
............................................ 2
4.4 Density of recording
.......................................... 2
4.5 Flux transition spacing
3
Average Signal Amplitude .
4.6
3
4.7 Byte .
3
Sector .
4.8
3
Cylinder .
4.9
3
Cylinder number .
4.10
......................................... 3
4.11 Data capacity of a track.
3
4.12 Hexadecimal notation .
................................. 3
4.13 Error Detection Characters (EDC)
3
5 Tracklayout .
3
5.1 IndexGap. .
3
5.2 Sector Identifier .
4
5.3 Identifier Gap .
4
5.4 DataBlock .
4
5.5 Data Block Gap .
4
5.6 TrackGap .
. . .
Ill

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SIST EN 28860-2:1997
IS0 8860-2 : 1987 (E)
Coded representation of data . 4
6
6.1 Standards . 4
6.2 Coding methods . 4
Annexes
6
A EDC implementation .
............. 7
B Procedure and equipment for measuring flux transition spacing
C Data separators for decoding MFM recording . 9
Bibliography . 10
iv

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SIST EN 28860-2:1997
IS0 8860-2 : 1987 (E)
INTERNATIONAL STANDARD
Data interchange on SO mm
Information processing -
(3.5 in) flexible disk cartridges using modified
frequency modulation recording at 7 958 ftprad on
80 tracks on each side -
Part 2 -I
Track format
0 Introduction IS0 8860-1, Information processing - Data interchange on
90 mm (3.5 in ) flexible disk cartridges using modified frequent y
IS0 8866 specifies the characteristics of 90 mm (3.5 in) flexible
modulation recording at 7 958 ftprad on 80 tracks on each
disk cartridges recorded at 7 958 ftprad using Modified Fre- side - Part 1 : Dimensional, physical and magnetic charac-
quency Modulation (MFM) recording on 80 tracks on each side.
teris tics.
IS0 8860-l specifies the mechanical, physical and magnetic IS0 9293, Information processing - Volume and file structure
characteristics of the cartridge, so as to provide physical inter-
of flexible disk cartridges for information interchange.
changeability between data processing systems.
IS0 8866-l and IS0 8860-2, together with the labelling scheme
4 General requirements
specified in IS0 9293, provide for full data interchange between
data processing systems.
4.1 Mode of recording
1 Scope and field of application
The mode of recording shall be Modified Frequency Modula-
tion (MFM) for which the conditions are
This part of IS0 8866 specifies the track layout, the track
format and the characteristics of recorded signals.
a) a flux transition shall be written at the centre of each bit
cell containing a ONE;
NOTE - Numeric values in the SI and/or Imperial measurement
system in this part of IS0 8860 may have been rounded off and
therefore are consistent with, but not exactly equal to, each other.
b) a flux transition shall be written at each cell boundary
Either system may be used, but the two should be neither intermixed
between consecutive bit cells containing ZEROS.
nor re-converted. The original design was made using SI units.
Exceptions to this are defined in 4.12.
2 Conformance
4.2 Track location tolerance of the recorded
A 90 mm (3.5 in) flexible disk cartridge shall be in conformance
flexible disk cartridge
with this part of IS0 8866 if it meets all mandatory requirements
contained herein.
The centrelines of the recorded tracks shall be within + 0,028 mm
A prerequisite for conformance with this part of IS0 8866 is
( + 0.001 1 in) of the nominal positions and over the range of
conformance with IS0 8866-l.
operating environment specified in IS0 8860-l.
3 References
4.3 Recording offset angle (see figure 1)
IS0 646, Information processing - /SO 7-bit coded character
At the instant of writing or reading a magnetic transition, the
set for information interchange.
transition shall have an angle of
IS0 2022, Information processing - IS0 7-bit and g-bit coded
character sets - Code extension techniques.
IS0 4873, Information processing - IS0 g-bit code for infor-
where R, is the radius through that transition (see IS0 8866-l 1.
Structure and rules for implementation.
ma tion interchange -
1

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SIST EN 28860-2:1997
IS0 8860-2 : 1987 (E)
4.4.2 The long-term average bit cell length shall be the
average bit cell length measured over a sector. It shall be within
+ 2,0 % oi the nominal bit cell length.
. 4.4.3 The short term average bit cell length, referred to a par-
ticular bit cell, shall be the’ average of the lengths of the
preceding eight bit cells. It shall be within + 8 % of the Iong-
term average bit cell length.
4.5 Flux transition spacing (see figure 2)
The instantaneous spacing between flux transitions is in-
fluenced by the reading and writing process, the bit sequence
(pulse crowding effects) and other factors. The locations of the
transitions are defined as the locations of the peaks in the signal
I
when reading. Tests should be carried out using a peak-sensing
amplifier (see annexes B and C).
d
-L-
, d =0,35mm(O.O14in)
4.5.1 The spacing between the flux transitions in a sequence
of ONES shall be between 80 % and 120 % of the short-term
Figure 1
average bit cell length.
NOTE - As tracks may be written and overwritten at extremes of the
4.5.2 The spacing between the flux transition for a ONE and
tolerances given in 4.2 and 4.3, a band of old information may be left at
that between two ZEROS preceding or following it shall be
one edge of the newly written data and would constitute unwanted
noise when reading. It is, therefore, necessary to trim the edges of the between 130 % and 165 % ot the short-term average bit cell
tracks by erasure after writing.
length.
4.4 Density of recording
4.5.3 The spacing between the flux transitions of two ONES
4.4.1 The nominal density of recording shall be 7 958 ftprad. surrounding a ZERO shall lie between 185 % and 225 % of the
The resulting nominal bit cell length is 125,7 prad. short-term average bit cell length.
. 0
1
I
I
4
I
I. I I
t
130% to 165'/0 130°h to 165'/0 185'/0 to 225%
Figure 2
2

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SIST EN 28860-2:1997
IS0 8860-2 : 1987 (El
(FE) for (88 to Bl) = 11111110
4.6 Average Signal Amplitude
(FB) for (B8 to Bl) = 11111011
For each side the Average Signal Amplitude on any track of the
(Al)* for (B8 to Bl) = 10100001
interchanged flexible disk cartridge shall be less than 360 % of
SRA
...