Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E 165
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continued from previous page
The control mode page (Table 5.2.1-28) provides controls over several SCSI-2 features which are applicable
to all device types such as tagged queuing, extended contingent allegiance, asynchronous event notification,
and error logging.
Notes.
[1] The PS (Parameter Savable) bit of 1 indicates that the page 0Ah parameter data is savable in non-
volatile memory.
[2] A report log exception condition (RLEC) bit of one specifies that the target shall report log exception
conditions. A RLEC bit of zero specifies that the drive does not report Log exception conditions.
[3] The queue algorithm modifier field specifies restrictions on the algorithm used for re-ordering commands
that are tagged with the SIMPLE QUEUE TAG message.
Table 5.2.1-29. Queue Algorithm Modifier
Value
Definition
Value
Definition
0h
Guaranteed data integrity
2h - 7h
Reserved
1h
Unrestricted re-ordering allowed
8h - Fh
Vendor Speific
A value of 0h in the Queue Algorithm Modifier bits requires the device to order the actual execution
sequence of the queued command such that data integrity is guaranteed at any time. This requires that,
if the data transmission of a command was halted at any time, the final value of all data must have exactly
the same value it would have had if the command had been executed without queuing. The guaranteed
data integrity value (0h) of the queue algorithm modifier bits is the usual default value.
A value of 1h in the Queue Algorithm Modifier bits allows the device to order the actual execution se-
quence of the queued commands in any manner it selects. Any data integrity problems related to com-
mand sequence ordering are explicitly handled by the host operating system software.
[4] A Queue Error Management (QErr) bit of zero indicates that those commands still queued after the
device has entered the contingent allegiance condition continue execution in a normal manner when that
condition has terminated. A QErr bit of one indicates that those commands still queued after the device
has entered the contingent allegiance condition shall be aborted when that condition has terminated. A
unit attention condition is created for each initiator that had commands in the queue, but not for the
initiator detecting the original error.
[5] A Disable Queuing (DQue) bit of one indicates that tagged queuing is disabled on the disc drive. Any
pending commands in the queue for that I T X nexus is aborted. Any subsequent queue tag message
received shall be rejected with a Message Reject message and the I/O process shall be executed as an
untagged command. A DQue bit of zero indicates that tagged queuing is enabled, if the drive supports
taggged Queing.
[6] An Enable Extended Contingent Allegiance (EECA) bit of one indicates that the device has enabled the
extension of the contingent allegiance condition. An EECA bit of zero indicates that the extension of the
contingent allegiance condition is disabled.
[7] See drive Product Manual Mode Sense Data section for changeable values.
[8] The Busy Timeout Period field specifies the maximum time, in 100 millisecond increments, that the
initiator allows for the target to remain busy for unanticipated conditions that are not a routine part of
commands from the initiator. This value may be rounded down as defined in section 4.8 of this manual. A
0000h value in this field is undefined by this specification. An FFFFh in this field is defined as an unnlimited
period.
[9] GLTSD: Global Logging target save disable bit of zero allows the target to provide a target-defined
method for saving log parameters (Logged to disk). A GLTSD bit of one indicates that either the target
has disabled the target-defined method for saving log parameters or when set by the initiator specifies
that the target-defined method shall be disabled.
[10] RAC: Report a check. Not used at this time.
