Discussion of tape alert behavior for SSC

robbyb at us.ibm.com robbyb at us.ibm.com
Tue May 11 16:09:54 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* robbyb at us.ibm.com
*


IBM prefers that tape alert conditions not be cleared until the underlying
cause is corrected.  It may be that this needs to be selectable by some
Mode Page setting.  In that case, the default setting is
that tape alert conditions not be cleared until the underlying cause is
corrected.  A natural periodic event on which to report these conditions
would be an Unload.




* From the T10 Reflector (t10 at symbios.com), posted by:
* Bob Snively <Bob.Snively at Ebay.Sun.COM>
*

At present, tape alert conditions are cleared and not re-established
whenever the tape alert condition is sensed.  This prevents the
possible filling of logs with conditions that may be present for
a long time, but would otherwise have no effect on normal operation.

I have recommended that tape alert conditions not be cleared until
the underlying cause is corrected.  My reasoning is that there may
be a significant number of independent processes and distributed hosts operating
with a tape device, each of which should become aware of the
problem being presented by the tape alert condition.  Individual
processes could then choose to log or not to log duplicate conditions.

A sort of compromise would be achieved by treating tape alert as
a unit attention  would be treated.  That requires that the tape
alert be presented once for each requesting initiator, but assumes that
within an initiator, all processes that need to know will be
informed of the problem by the process that obtained the tape alert
condition.

What do you folks think about this?



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Bob Snively                   Phone:       (510) 574-9051
Sun Microsystems Computer Company
Mail Stop NWK 04-104
901 San Antonio Road                  E-mail: bob.snively at sun.com
Palo Alto, CA 94303
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