Machine check, type 0 (VAX 780)

[Alan Fargusson]

> > > Does anyone know what 'Machine check, type 0' is on a VAX 780?
> > > The message also says 'CP read timeout fault' and prints some
> > > registers, but I can't find any documentation around here that
> > > describes things like that. We have goten four of them since

It looks like some of my postings didn't make it to the net. The problem
went away after I recompiled the device drivers. It looks like the System V
distrubution has a bug in it. The makefile for the device drivers does the
following:
	cc -O -I/usr/include -S gd.c
	ed - gd.s <../spl.ed
	/lib/c2 -y gd.s gd.os
	as -o gd.o gd.os
	rm -f gd.s gd.os
	ar rv ../lib2 gd.o

The 'cc' line has the -O flag set which seems to cause the optimiser to
insert some instructions which don't work correctly on device registers
on the VAX. This is obviously a mistake anyway because the optimiser is
used again on gd.s with the magic -y flag. Removing the -O from CFLAGS in
the makefile seems to fix all kinds of funny things with disk and tape drives.
-- 

Alan Fargusson.

{ ihnp4, amdahl, mot }!drivax!alan