User's Guide

Commands: Mode Select (15h) Page 73
MODE SELECT (15h)
The MODE SELECT command allows the host to assign device parameters.
After a power-on or SCSI reset condition, the drive sets its device parameters to the
default values. By issuing a MODE SELECT command, the host can change the
device parameters. The parameters are transferred to the drive as data formatted in
a parameter list.
Parameters assigned by the MODE SELECT command remain in effect until the
drive receives a subsequent MODE SELECT command or a reset. The MODE
SELECT parameters are not unique to the initiator that assigned the parameters.
The MODE SELECT command immediately checks for invalid parameters or invalid
combinations of parameters before executing. If an exception is found, the drive
returns a Check Condition, and the request sense data is set to Illegal Request.
You can issue a MODE SENSE command following a MODE SELECT command to
determine which parameters (if any) were rounded to the nearest supported value.
MODE SELECT Command Descriptor Block
The following table shows the layout of the CDB.
Byte
Bits
7 6 5 4 3 2 1 0
0 0 0 0 1 0 1 0 1
1 0 0 0 PF 0 0 0 0
2 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
4 Parameter List Length
5 vendor unique* 0 0 0 0 Flag Link
* This vendor-unique field is reserved and must be set to zero.