SCSI error -- medium changed in drive

[Lauren Weinstein]

Greetings.  Has anyone else seen this message from the system under
ix2.0.2?

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*** DEVICE ERROR: Medium has been changed in drive ***
*** Controller 1 (Adaptec AHA-1540 SCSI Host Adapter), DISK Drive 0,
    Absolute Sector # 43014 ***
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This was for a 660MB disk on the 1540.  The disk had been running
fine up to this point (as long as certain I/O cards which the 1540
doesn't like weren't in the system, but that's a story for another
time) then this message popped up out of the blue last night.

My first thought was that a sector remapping had occurred, but the
grown list for the disk shows no changes.

Does this look familiar to anyone?  Thanks.

--Lauren--