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BIT
BYTE
7
6
5
4
3
2
1
0
00
---------------~i;~I;~~;~~I~~d~-:10i----I------I------
01
02
03
04
05
06
07
08
09
MSB
MSB
MSB
Cylinder Count
Cylinder Count
Data Head Count
Reduced Write Current
Reduced Write Current
Write Precompensation
Write Precompensation
Landing Zone Position
Step Pulse Rate
Figure 6-25.
Drive Parameter List for
Soft-Sectored, Fixed Drives
I
LSB
I
LSB
I
LSB
The List Format Code must be set to 01 for soft-sectored drives
and 02 for hard-sectored or removable drives.
The Cylinder Count is the numbe of data cylinders on the drive.
The ACB-5500 does not use alternate cylinders for defect
management, so these may be included as data cylinders.
The
minimum number of cylinders is one, the maximum is 2048.
The Data Head Count is the number of usable data surfaces.
The
minimum is 1, the maximum is 16.
A drive with 9 or more heads
. will use the Reduced Write Current line as the high-order head
select.
The Reduced Write Current cylinder is the cylinder number beyond
which the controller will assert the Reduced Write Current line.
The minimum value is 0.
Note that the reduced write current line
is used as a fourth head select line for drives with more than 8
heads.
The Write Precompensation cylinder is the cylinder beyond which
the controller will compensate for inner track bit shift.
The
minimum value is 0.
500504-00
6-33
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