table above. This value will be lower than the usable drive
capacity.
In a few situations, none of the drive types specified in your BIOS
setup program will match your drive, and the setup program will
not provide an opportunity to specify a custom drive type. In this
case, consider the third option described above — allowing your
ST9235 family drive to mimic one of the BIOS-supported drive
types. During the BIOS setup process, simply select a drive type
with a capacity that is

less than or equal to

the drive’s BIOS
calculated capacity listed in the table on page 6. This drive type
should have no more than 16 read/write heads or 63 sectors per
track. In addition, the total number of sectors for that drive type
(listed in the setup program) should not exceed the number of
cylinders times the number of read/write heads times the number
of sectors per track. In other words:

Total sectors per drive

≤
(

No. cylinders

) × (

No. read/write heads

) × (

No. sectors per track

)
BIOS compatibility recommendations
The ST9235 family drives are AT interface compatible drives,
which conform to ATA specifications. The host system BIOS must
provide support for the AT interface command set. Consult the
system documentation for information on the AT interface within
your system. Several key compatibility issues are discussed
below.
In accordance with ATA specifications, the BIOS must reset any
emulation/translation parameters after a hard reset is received
from the host.
In some configurations, the ST9235 family AT interface drives
supply 11 bytes of Error Correction Code (ECC) with the Read
Long and Write Long commands. Depending on the drive type,
ST9235 Family Installation Guide, Rev. B 7