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FORMATTING
6.3
Figure
22 illustrates a suggested format example.
INTER
RECORD GAP
WRITE
TURN-OFF
GAP
ADDRESS
MARK
DATA
CRC
DATA SYNC
VFO LOCK
SYNC BYTE
WRITE
TURN-ON
GAP
FIELD
NAME
ID VFO LOCK
ADDRESS
MARK
CYLINDER
NUMBER
HEAD
NUMBER
SEClOR
NUMBER
CRC
SYNC BYTE
3
3
2
2
15
13
512
2
NUMBER
OF BYTES
13
9
5
7
S
6
2
4
3
14
11
10
12
13
15
REFERENCE
NUMBER
1
FIGURE 22:
17 Sector,
512-Byte/Sector
Format Example
FIELD DESCRIP110N
A field of ail zeros to sync the VFO for
the ID
"Al" Hex with a dropped clock to noti-
fy the controller that data follows.
"FE" Hex defining that ID field data
follows.
A numerical value in Hex defining the
detent position of the actuator.
A numerical value in Hex defining the
head selected.
A numerical value in Hex defining the
sector for this section of the rotation.
Cyclic Redundancy
Check information used to verify the
validity of the ID field information just
read.
Zeros written during format to isolate
the write splice created. This field
assures valid reading of field number 7
and allows the 13 bytes required for
Data VFO lock.
A field of all zeros to sync the VFO for
the data field.
"Al" Hex with a dropped clock to noti-
fy the controller that data follows.
"FS" Hex defming that user data
follows.
This area available for user data.
Cyclic Redundancy
Check information used to verify the
validity of the user data field informa-
tion just read.
Zeros written during update to isolate
the write splice created. This field
assures valid reading of field number 13
and allows the 13 bytes required for
VFO lock for the ID field of the next
sector.
A field of all zeros which acts as a
buffer between sectors to allow for
n
speed variation.
n
~
Il.---
----.JI L
14
1
15
L~
/:~x~~
(NOMINAL)
12
1
13
1
11
10
1
9
8
571 BYTES TOTAL
)K
1
GAP 1
/16X4E
ID FIELD
GAP 2
DATA FIELD
INTER·RECORD GAP
IOVfO
SYNe
AoOR
CYLINDER
HEAD
SCTA
WRITE
DATA SYNC
SYNe
AoOR
WAtTE
INTER-
LOCK
BYTE
MARK
ADDR
NO
NO
CAC
TURN.()N
VFD
BYTE
MAAK
DATA
CAC
TURN<JFF
AECORD
GAP
LOCK
....
GAP
NUMeEA
13
Of
BYTES
2
2
13
512
2
3
15
FELONO
1
2
3
4
5
6
7
9
10
11
12
13
,.... only)
14
15
STl12 PRODUCT MANUALIRev. B
25
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