What does "Bad command synchronization" mean?

[Tony Tran]

Yesterday morning when I came in to work, I found 2 out of 3 tape drives 
no longer work. The error messages are:

Mar 28 10:30
xt0: lost interrupt
xt0: hard error bn=0 er=4
xt: bad command synchronization
xt: bad command synchronization
xt0: stray interrupt
xt0: hard error bn=0 er=16
xt0: hard error bn=0 er=16
xt0: hard error bn=0 er=16

I am able to back up some small partitions, like root, /pub, but no longer
back up 100 MB+ partitions, because the dump will abort after about 15% 
completion or sooner. 

I have put a service call to SUN, and am waiting for them to call me back.
In the meantime, no daily backup or weekly backup.

I recall seeing this mentioned somewhere in the net, but I just cannot 
remember all the gory details about it. It has something to do with a
fix from SUN or something. 

Has anybodyseen this kind of errors? Any hint/advise would be appreciated.

Tony Tran
Versatec Corp.

PS: Yes, I did clean the tape head many times. And yes, I did use
various brands of tapes, including brand new tapes too.

These are SUN servers 3/160; 3/180 with original SUN equipments
(Super Eagle 2361k and tape drive I believe from Fujitsu (?).
We did manage to add a couple of M2372k Swallow disks on these.
They are running SUN OS 3.4  if it helps any.)
-- 
UUCP: {sun,ames,pyramid}!versatc!tran  	Tony Tran
ARPA: tran at arisia.xerox.com 
Versatec, 2805 Bowers Avenue, Santa Clara, Calif 95051 (408)982-4317
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