Product manual

3.4.10.1 Mode Select parameter list
The Mode Select parameter list contains a 4-byte header, followed by a
1-block descriptor (if any), followed by the pages of Mode Select parame-
ters.
Each block descriptor specifies the media characteristics for all or part
of a logical unit. The rest of the Mode Select parameters are grouped by
function and organized into mode pages. The mode pages are described
in Appendix A.
Bit
Byte
7 6 5 4 3 2 1 0
Parameter list header
0 (default) Reserved (00
H
)
1 (default) Medium type (00
H
)
2 (default) Reserved (00
H
)
3 (default) Block descriptor length (00
H
or 08
H
)
Block descriptor data
4 (default) Density code (00
H
)
5–7 Number of blocks
8 (default) Reserved (00
H
)
9–11 Block length
Parameter information
12–
n Mode pages
Byte 1 The
medium type field is always 00
H
, which means that the
drive is a direct access device.
Byte 3 If the
block descriptor length is 8 bytes, a block descriptor
is sent to the drive. If the
block descriptor length is 0 bytes,
no block descriptor is sent to the drive.
Byte 4 The
density code is always 00
H
and cannot be changed.
Bytes 5–7 The
number of blocks is equal to the guaranteed sectors,
which is listed in the formatted capacity section of the
appropriate product manual.
Bytes 9–11 The
block length is always 512 and cannot be changed.
50 ST3655 Family SCSI Drives Product Manual, Rev. A