disk sequencer error

[Dinah Anderson]

> xy0a: read retry (disk sequencer error) -- blk #495, abs blk #495

>Is this a serious disk problem that I should worry about?  The system
>seems to be working well.  What is a disk sequencer error?  Would diag
>have to be used to fix this problem?  

We have received these errors on several different systems (several
different controller/disk combinations.) Sometimes the disk stops working
and sometimes we get a couple of the error messages and then things
proceed normally. 

I would like to know what the errors mean and under what circumstances
they occur. I would also like to know what we should do about them.

Dinah Anderson 
Shell Oil Company, Information Center (713) 795-3287
...!{sun,psuvax,soma,rice,ut-sally,ihnp4}!shell!dinah