Product manual

Byte 2
The
initiator control (IC) bit is not supported.
When the
abort prefetch (ABPF) bit is 0, the drive controls
completion of prefetch. See the description for the DISC
bit below. This is the default value and it is not change-
able.
The
caching analysis permitted (CAP) bit is not sup-
ported.
When the
discontinuity (DISC) bit is 1, the drive may
prefetch across cylinder boundaries, where head seeks
consume additional processing time. This is the default
value and it is not changeable.
The
size enable (SIZE) bit is not supported.
When the
write cache enable (WCE) bit is 0, the drive
returns a good status for a Write command after success-
fully writing all the data to the media. When the WCE bit
is 1, the drive returns a good status for a Write command
after successfully receiving the data and usually before
writing it to the media.
When the
multiplication factor (MF) bit is 0, the drive
interprets the
minimum prefetch and maximum prefetch
fields as the number of logical blocks to be prefetched.
When the MF bit is 1, the drive interprets the minimum
prefetch and maximum prefetch fields in terms of a num-
ber which, when multiplied by the transfer length of the
current command, yields the number of logical blocks to
be prefetched.
When the
read cache disable (RCD) bit is 0, the drive may
return data requested by a Read command by accessing
either the cache or the media. If the RCD bit is 1, the cache
is not used.
Byte 3
The
demand read retention priority field is not used. The
initiator cannot assign any special retention priority to the
drive.
The
write retention priority field is not used. The initiator
cannot assign any special retention priority to the drive.
Bytes 4–5
The
disable prefetch transfer length always has a value
of FFFF
H
, which means that the drive attempts an antici-
patory prefetch for all Read commands.
Bytes 6–7
The
minimum prefetch field specifies the minimum num-
ber of blocks the drive prefetches, regardless of the delays
it may cause in executing subsequent pending com-
mands. When the minimum prefetch field contains 0, the
Medalist Pro 2160N/2160WC Product Manual, Rev. A 111