SCSI-2 Parity Errors
gerry at ciprico.com
Thu Mar 16 14:43:44 PST 1995
As a manufacurer of both SCSI host adapters and SCSI targets, disk
arrays, I wholeheartedly agree with Jim McGrath's comments pertaning
to the uselessness of complicated error recovery procedures ala
restore pointers message. In our target devices, and most current
drives we have tested, a command or data out parity error results only
in the return of a check condtion status and appropriate sense data.
Our host adapter experiance with the restore pointers operation
particularly when combined with scatter/gather transfers indicated it
was more trouble to impliment then it is worth.
Since most parity errors result from improper cabling or termination
forwarding the error to the host for action makes the most sense.
Since this subject has generated so much traffic, I would like to
gauge support for a simplified SCSI-3 document which would describe
only the most basic subset of features required to impliment a
host adapter to drive SPI connection. I have considerable sympathy
for the engineer assigned to connect a drive to his host system
who needs to wade through 1000's of pages on multiple SCSI-3 documents
to do his job.
Gerry Johnsen Ciprico Inc
(612)551-4000 2800 Campus Drive
gerry at ciprico.com Plymouth, MN 55418
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