SECTOR
IDENTIFIER
The
sector
identifier
consists of the identi-
fier
mark,
the address
identifier and
the
EDC
pattern.
IDENTIFIER
MARK
This field
comprise
7
bytes
(see Fig.
1-6).
The 6
bytes
of
zeros
in
front of the
address
mark
byte are
for synchronisation of the data
separator in
the host system. The
ID-AM-
byte
.contains a data
pattern of FE
where
the
clock
bits C6,
CS and C4 are
missing
as
explained
before
.
2ND
BYTE
OF
THE ADDRESS IDENTIFIER
This byte
contains always
00.
SECTOR
ADDRESS
Represents
in
binary notation the sector
ad-
dress from
01 for
the 1st sector to 16
for
the last
sector
of a
track.
4TH
BYTE OF
THE
ADDRESS
IDENTIFIER
This
byte
shall be
always
a
(00-)-
byte.
ADDRESS
IDENTIFIER
The address identifier comprises the following
6
bytes.
TRACK
ADDRESS
This
byte represents in
binary notation the
track address
from
00
for the outermost track
to 39 for the
innermost track.
EDC
-
BYTES
These
two
bytes are
hardware generated from
the host system by
shifting
serially the bits
of the sector
identifier
starting
with
the ID
-
AM
and ending with the 4th byte of
the
sec-
tor identifier through a
16-
bit shift regis-
ter described by the generator polomial
:
.16
x
12
x
5
1
(Fore more details read chapter
EDC-
entation!
)
imple-
IKDEX
GAPl
SECTOR IDENTIFIER
IDENTIFIER
GAPfFIRST DATA BLOCK] DATA
BLOCK
CAP
f||LAST DATA BLOCK! DATA BLOCK
GAPlTRACK
GAPi
ss
16
X FF
13 BYTES II X
FF
137
BYTES
27
X
FF
137
BYTES 27 X FF
1
1
HI
Mil -
I—.
I. »
— !M
-I!
I.
JO!
X FF
r~T_
INDEX PULSE
SECTOR IDENTIFIER:
IDENTIFIER MARK
ADDRESS IDENTIFIER
EDC
6
X 00
FF.
T)
TRK 00
SEC 00
2 BYTES
C7
2)
ID-
AM
DATA
BLOCK:
DATA
MARK
DATA
FIELD
EDC'
6
X 00
n
iy.
1 2 S
BYTES
2 BYTXS
C7
2)
DATA-AM
1)
DATA
PATTERN
2)
CLOCK PATTERN
•
DELETED
AM
t Ft
ID
-
AM.
SEP
CLOCK (C7)
SEP
DATA
(PE)
DATA
-
AM:
SEP CLOCK
(C7)
SEP DATA
(PS)
Ps S
'
I
BYTE
S S
C
6 S
C
•
• ••
4
S
*7
°\
I I I I
8
D
5
D
4
°3
4
>8
»>
h
I
I I
1
I I I
JCj
cj
Cj c
5
c
4
c
3
cj
c,
|r
n n p
Dg
D,
D
§
Dj D*
D
2
D,
DELETED
DATA
-
AH:
JB
C
7
Cj
C
5
C*
Cj
%
C,
•» clock
(CD
iinnniiii
D
8
D
7
D
6
Ds
D*
FIGURE
1
-
6 .
SOFT
SECTORED
TRACK
FORMAT
WITH
16
SECTORS/TRACK
1
-
7
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