Gerald,

We have a 3494 Tape Library connected to our H50 running TSM and
occasionally get errors (though not the same as yours) when we have heavy
tape usage (ie: copypool reclaimation) between cleaning cycles.

The library cleans the drives each day and when this occurs, our AIX error
log contains the SIM/MIM record you refer to.  When it first appeared back
when we started using ADSM, I was told by AIX support that the error log is
just recording the tape drive being cleaned.

As long as you do not have consistent drive errors, I would not be overly
concerned.

Tom Bebee