Mode Select(6) (15H) - Pioneer SCSI-2 Reference Manual

2.5

Mode Select(6) (15h)

The MODE SELECT(6) command provides a range for the initiator specifying specific operating
parameters, e.g., medium, logical unit and peripheral device parameters.
IMPORTANT: Initiators should issue the MODE SENSE command (reference Section 2.7)
prior to each execution of the MODE SELECT command to determine supported pages, page
lengths and other parameters.
Operating Code is (15h).
PF (Page Format)
Must be set to "1" (TRUE). The drive does not check the value of the Page Format bit.
SP (Save Parameters)
Must be set to "0" (FALSE). Parameter saving is not supported.
Parameter List Length
If "0" (ZERO), no data will be transferred.
The Parameter List Length is the number of bytes of the Mode Select Parameter List that is
to be transferred in the Data Out phase. A parameter list length that results in the truncation
of any descriptor, header or page parameters will cause the target to terminate the
command. In this case Check Condition Status (Sense Key : Illegal Request) is returned
and Sense Code is set to Parameter List Length Error.
Using the MODE SELECT command, the initiator can assign or alter parameters for the logical
units. The Parameter List includes a 4-byte header, followed by 0-1 block descriptors and 0-N,
where N is a whole number, page descriptions. Refer to Table 2-5A on the opposite page. The
drive keeps parameters, the block descriptor and parts of page descriptors for each logical unit in
its controller memory. When the drive is reset, the default parameter values are restored.
Refer to Table 2-5B on the next page for details on the Block Descriptor format.
Refer to Table 2-5C on the next page for details on the Page Descriptor format.
After the MODE SELECT command is received, the drive returns Check Condition Status
(Sense Key : Unit Attention) and sets sense key to Mode Select Parameter Changed for the first
command received (except for INQUIRY or REQUEST SENSE) from any other initiator. The
Sense Key Unit Attention is returned even if the parameters have not actually changed with the
MODE SELECT command.
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Mode Select(6)