Question: Deferred Sense reporting priority

Gerry_Houlder at Gerry_Houlder at
Fri Apr 24 15:27:36 PDT 1998

* From the T10 (formerly SCSI) Reflector (t10 at, posted by:
* Gerry_Houlder at
Most targets only retain the "latest" sense data rather than remember the
last N events. In this case, only the last sense event is retained and
reported. If you choose to remember more than one event (i.e., after
reporting one set of sense data, the next command will also get CHECK and
another set of sense data will get reported, etc) I recommend the following
priority for sense reporting (highest to lowest):
(a) Unit Attentions (resets, media change)
(b) Deferred errors (reporting problem with some previous command)
(c) Current errors (reporting problem with current command)

If the target chooses to only remember the last event, some prioritizing
may still occur. For example deferred error sense may be replaced by unit
attention sense bytes but  unit attention sense may not be replaced by
deferred error or current error sense (i.e., those new sense bytes are

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