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

[George D M Ross]

In article <136 at uwslh.UUCP> dem at uwslh.UUCP writes:
>We are running a VAX-11/750 with 4.2BSD unix.
>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).
>Occasionally (usually about once a month but last week as much as 5 times
>per day) the computer will hang as though a task completion interrupt from
>the disk had been lost.  Pressing the reset switch on the controller will
>cause the system to pick up running as though nothing had happened.
>-- 
>David E. Miran         ...!{seismo,harvard,topaz,ihnp4}!uwvax!uwslh!dem

We too have experienced this problem.  Our configuration is a 750 running
4.2BSD with a SI 9900 controller and a couple of Eagles.  We are running the
SI hp driver (you need it if your drives have any bad blocks).  The symptoms
were exactly the same -- occasionally the system would hang until the reset
switch on the 9900 was pressed, at which time the driver would wake up and
things would take off again.

Our controller was replaced (to fix a different problem) but the effect
persisted, so it looks like it's not a controller problem per se.  However,
several months ago we had a big hefty earthing cable connected between the
controller and the 750, since when we haven't seen the effect.  Coincidence,
maybe....?

-- 
George D M Ross, Dept. of Computer Science, Univ. of Edinburgh, Scotland
Phone: +44 31-667 1081 x2730
JANET: gdmr at UK.AC.ed.cstvax  --> ARPA: gdmr at cstvax.ed.AC.UK
UUCP:  <UK>!ukc!cstvax!gdmr