Console hangs on Vax 780 4.2BSD

[David Melman]

This is concerning a Vax 780 running 4.2BSD.

We have an intermittent problem where processes will hang when
attempting to write to the console, a DECWRITER III.  It has been
occuring several times a month.

This, of course, is quite serious.  It even precludes an 'su root'
which must write to the console!

We reboot with great frustration when this occurs, which has
always cleared the problem.

Sometimes this 'hung-console' problem results in a crash with the following
message on the console:

?UNEXPECTED TRAP
	MOUNT CONSOLE FLOPPPY, THEN TYPE ^C  	(operator then types ^c)
	CPU RUNNING, SOMM CLEAR,STEN=NONE,CLOCK=NORM
	RAD=HEX,ADD=PHYS,DAT=LONG,FILL=00,REL=00000000
	(RELOADING WCS)
	?CPU NOT IN CONSOLE WAIT LOOP,FUNCTION ABORTED
	VER: PCS=00 WCS=00-00 FPLA=2F CON=V05-00-L	
?WARNING-WCS & FPLA VER MISMATCH
>>>
	

Any pointers regarding this problem would be most appreciated.

David Melman
System Development Corporation - Santa Monica
(213) 820-4111 X5367

UUCP: {ihnp4,hplabs,sdcsvax}!sdcrdcf!davem