disk system hangs on a VAX-750 with SI controller.

[Lee Ward]

> The disk system is a Systems Industries 9900 controller with a Fujitsu
> eagle disk drive and two CDC 9730-80 disk drives (a sealed 67 M drive).
> The controller emulates a massbus device and we use the hp device driver
> that came with 4.2BSD.

We had the same problem a couple of years ago and then the HDA on the
eagle took a hike somewhere. After replacement everything went fine.
The symptoms were exactly as you describe.

At unm-la on a 750 with EMULEX controller and eagles it happens to them.
Their cure: Don't ever, ever power the line printer on/off. It works
like magic.

Currently, we are having the problems you describe once again. One exception
though. The reset switch no longer lets the OS continue. Unix is up
and going through the scheduler. As long as a process doesn't go to the
disk everything is fine. We know it is the SI9900/eagles. We think a bad block
of some sort on the eagle aggravates a problem in the controller and everything
hangs up. We can reproduce the effect at any time, by simply backing up
/usr! We have had our controller worked on to no avail. We have used
two versions of the SI drivers and the berkeley one (modified to print
out the real address on error) and we get the same behavior. We are EXTREMELY
sick of the problem and would also appreciate any insights. Many people
have suggested that we just reformat the /usr partition/disk. We want the
problem to go away, not just work around it to find it again later.

-- 
			--Lee (Ward)
			{ucbvax,convex,gatech,pur-ee}!unmvax!lee