Product manual

C.5.2 Write caching and write merging
Write caching. The drive uses the write segment to store write com-
mands and data. After the drive caches the commands and data, it is
immediately ready to process new commands. The drive writes the data
to the disc at its next convenient opportunity.
Write merging. The drive accepts contiguous write commands and
executes them sequentially as one command.
C.5.3 Caching page description
The Caching page is shown below. This table summarizes the function,
the default value and the changeability of each bit.
Bit
Byte
7 6 5 4 3 2 1 0
0 PS (1) Page code (08
H
)
1 Page length (12
H
)
2 IC ABPF CAP DISC SIZE WCE MF RCD
default 1 0 0 1 0 1 0 0
changeable 1 0 1 0 1 1 1 1
3
Demand read
retention priority
Write retention priority
default 0 0 0 0 0 0 0 0
changeable 0 0 0 0 0 0 0 0
4–5 (default) Disable prefetch transfer length (FFFF
H
)
changeable 0000
H
6–7 (default) Minimum prefetch (0000
H
)
changeable 0000
H
8–9 (default) Maximum prefetch (FFFF
H
)
changeable FFFF
H
10–11 (default) Maximum prefetch ceiling (FFFF
H
)
changeable FFFF
H
12 FSW Rsrvd DRA Reserved
default 1 0 0 0 0 0 0 0
changeable 1 0 1 0 0 0 0 0
102 ST3655 Family SCSI Drives Product Manual, Rev. A