Optical Drive and Library SCSI-2 Command Reference

SCSI-2 Drive Command Set
Mode Select Command (15H)
Chapter 2 2-39
SCSI-2 Drive Commands
Control Mode Page 0AH
Queue Algorithm
Modifier The queue algorithm modifier field specifies restrictions
on the algorithm used for reordering commands that are
tagged with the Simple Queue Tag message.
DQue A Disabled Queuing bit of 1 indicates that command
queuing is disabled.
A Disabled Queuing bit of 0 indicates command queuing
is enabled.
A value of zero (0) in this field specifies that the target will order the
actual execution sequence of the commands with a SIMPLE QUEUE
TAG such that data integrity is maintained for that initiator.
A value of one (1) in this field specifies that the target may reorder the
actual execution of the commands with a SIMPLE QUEUE TAG in any
manner.
Table 2-33 Control Mode Page 0AH
Byte 7 6 5 4 3 2 1 0
0 Reserved (0) Page Code (0AH)
1 Page Length (06H)
2 Reserved (0)
3
Queue Algorithm Modifier
a
Reserved DQue
4-7 Reserved (0)
a.For 9.1 and 5.2 Gbyte Capacity drives only.
Table 2-34 Queue Algorithm Modifier
Value Definition
0H Restricted reordering
01H Unrestricted reordering allowed
2H - 0FH Reserved