We have a number of Sun clients, two of which have recently started
getting this failure in their nightly backups:

01/29/1995 18:36:29 ANS4253E File input/output error
01/29/1995 18:40:29 ANS4847E Scheduled event '87PSCHEDULE' failed.
   Return code = 4.

These machines had been being backed up successfully every night for
many months.  Then both began failing on the same night.  One "healed"
itself after two weeks, but the other is still failing.  They are both
running Version 1, Release 2, Level 0.3.  There really does not seem
to be anything wrong with their disks.  Suggestions?

Melinda Varian
Princeton University