Note that the final drive capacity shown by the CMOS and total
sectors cannot exceed the values indicated in the last column of
the following table as defined by the following equation:
(Sectors)×(Heads)×(Cylinders) ≤ Total Sectors per Drive
If your BIOS offers a “custom drive” or a “user-defined” drive type,
you may use one of the configurations listed below.
Model
MBytes
(F)
CMOS
MBytes (F)
Cyl.
R/W
Heads
Sect./
Track
Total
Sect. /
Drive
ST9051A 42.86 40.87 654 4 32 83,712
ST9051A 42.82 40.84 820 6 17 83,640
ST9052A 42.65 40.67 980 5 17 83,300
ST9077A 64.05 61.09 802 4 39 125,112
ST9096A 85.29 81.34 980 10 17 166,600
ST9144A 127.94 122.02 980 15 17 249,900
The CMOS calculation of drive capacity is based on a variation
of the number of bits in a megabyte, for purposes related to drive
addressing.
When the drive geometry has been entered into the “user-de-
fined” or “custom” drive type, the CMOS may display the calcu-
lated drive capacity. This number should correspond with the
capacity listed in the “CMOS MBytes (F)” column of the table.
Note that the drive provides the user with full capacity as specified
in the “Mbytes (F)” column of the table.
After the high-level formatting has been completed, the drive
capacity can be verified using the DOS CHKDSK utility.
6 ST9144 Family Installation Guide, Rev. B
