RESERVATION CONFLICT AND ACA ACTIVE

Gerry Houlder Gerry_Houlder at notes.seagate.com
Tue Aug 16 08:17:33 PDT 1994


I agree that it would be good to explicitly define a priority order for the
various statuses and conditions, many of which can be simultaneously active.
Giles's example shows why it is important for all devices to use the same
prioritizing rules to prevent inter-operability problems.
 
However, I don't think it is a good idea to add wording in various spots to
define this priority. It is better to add a clause that specifically defines
the priority of the various statuses and conditions, so it is in only one place
in the document. Then the spot referred to by Giles (and other spots as well)
can use wording like "shall report [this condition] unless a higher priority
status or condition exists for that LUN". SCSI has always had wording like this
but has never defined what the priority should be.
 
The industry has been fortunate that most implementors have managed to come up
with the same priority order. This problem is going to get worse now that
tagged queuing and multiple initiators are more common. This greatly increases
the occurrance of simultaneous statuses and conditions within the target.
--
Gerry Houlder -- Gerry_Houlder at notes.seagate.com
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### OGATE Version 8 message trace and attachment information:
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### Org Date:    08-16-94 06:46:25 AM
### From:        Gerry Houlder at SEAGATE
### To:          scsi @ WichitaKS.NCR.COM @ internet
### Subject:     Re: RESERVATION CONFLICT AND ACA ACTIVE
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