Spectra Logic Spectra 12K User Manual page 162

Appendix B. Extended Copy—83h—SPC2 Specifications
CONDITION status; the sense key is set to ILLEGAL REQUEST, and the ASC and ASCQ indicate
OPERATION IN PROGRESS.
The Priority field establishes the priority of this EXTENDED COPY command relative to other
commands being executed by the same device server. All commands other than copy
commands have a priority of 1. Priority 0 is the highest priority, with increasing
Priority values indicating lower priorities.
A Sequential Stripped bit (STR) value of 1 indicates to the copy manager that most of
the disk references in the parameter list represent sequential access of several stripped
disks. This may be used by the copy manager to implement read-ahead. A STR value of
zero indicates to the copy manager that disk references are not necessarily sequential.
If the No Receive Copy Results (NRCR) bit is one, the application client will not send a
RECEIVE COPY RESULTS command to collect the results of this parameter list. If NRCR is zero,
the application client may send a RECEIVE COPY RESULTS command to receive the results of
this parameter list. The Target Descriptor List Length contains the length in bytes of the
target descriptor list that immediately follows the parameter list header. The number of
target descriptors equals the length in bytes of the target descriptor list divided by 32.
An EXTENDED COPY command may reference one or more target devices (which are the
source and/or the destination logical units). Each target device is described by a target
descriptor. All target descriptors have their formats specified by an EXTENDED COPY
descriptor code. A copy manager need not support all target descriptor formats.
Segment descriptors reference target descriptors by their position, or index, in the
target descriptor list. The index for a target descriptor is the starting byte number for
the target descriptor in the parameter data minus 12 divided by 32. The maximum
number of target descriptors permitted within a parameter list is indicated by the
Maximum Target Count field in the copy manager's operating parameters. If the
number of target descriptors exceeds the allowed number, the command will be
terminated with CHECK CONDITION status. The sense key will be set to ILLEGAL REQUEST, and the
ASC and ASCQ will indicate TOO MANY TARGET DESCRIPTORS.
The Segment Descriptor List Length contains the length in bytes of the segment
descriptor list that follows the target descriptors. The maximum number of segment
descriptors permitted within a parameter list is indicated by the Maximum Segment
Count field in the copy manager's operating parameters. If the number of segment
descriptors exceeds the allowed number, the command will be terminated with CHECK
CONDITION status. The sense key will be set to ILLEGAL REQUEST, and the ASC and ASCQ will
indicate TOO MANY TARGET DESCRIPTORS.
The maximum length of the descriptors (both target and segment) permitted within a
parameter list is indicated by the Maximum Descriptor List Length field in the copy
manager's operating parameters. If the combined length of the target and segment
descriptors exceeds the allowed value, the command will be terminated with CHECK
CONDITION status. The sense key will be set to ILLEGAL REQUEST, and the ASC and ASCQ will
indicate TOO MANY TARGET DESCRIPTORS.
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