Questions on XDWrite and XDRead commands
Warning: Dates in Calendar are closer than they appear.
rroche at tdh.qntm.com
Tue Jun 3 12:20:20 PDT 1997
* From the SCSI Reflector (scsi at symbios.com), posted by:
* rroche at tdh.qntm.com (Warning: Dates in Calendar are closer than they appear.)
*
In reviewing the XDWrite and XDRead commands in the SCSI-3 working draft,
I have come across the following problems.
If an initiator is using the XOR commands at queue depth, the drive may
run out of resources fairly quickly if no XDRead commands are issued. This
is due to the fact that XDWrite commands result in locking of cache segments
for retention of XOR result data.
Is there an assumption that most (all?) initiator will reserve the unit
or used linked commands to make the XDWrite/XDRead pair atomic?
In addition, if two overlapping XDWrites are issues and then followed by
an XDRead then what XOR result data should be returned? Is this
undefined?
Thanks,
Rick
rroche at tdh.qntm.com
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