not getting dump after crash (And flaw in uda50 driver)

[joe at ccnysci.UUCP]

> 
> Our 780 running 4.2 has been crashing with "panic: mchk,"  bet we are not
> getting crash dumps,  which makes it difficult to see what is happening.
> On other kinds of crashes we do not have this problem.  Any hints?  Is there
> a way to manually force a dump before rebooting?

I would have to guess that your system is configured with ra81 or ra80
disk drives. After having the same problem and assuming for a long time that
it was hardware related I discovered that the system core dump routine
for the uda50 disk controller is a dummy routine: It sets the global errno
variable to ENODEV and returns. By the time I discovered this the release
of 4.3 seemed immiment ( !!!! ) and so I decided to await the possibility
of a fix there.
	If anyone has a uda50 driver for 4.2 which includes a functional
dump routine, I would appreciate getting it, as would many other people
I'm sure.
	ihnp4!likewise!ccnysci!joe	(Joe Eccles)