fifo overflow?

[George Robbins]

In article <1895 at uakari.primate.wisc.edu> bin at primate.wisc.edu (Brain in Neutral) writes:
> 
> Ultrix 3.1, VAX 8200
> 
> Message on console:
> 
> dhu2: line 2: recv: fifo overflow
> 
> and machine is locked up.  Not crashed, but inert.
> 
> What's it mean?  Anything I can do about it?

FIFO overflow means that the serial interface received characters at a greater
aggregate rate than the CPU could process them and the FIFO (aka SILO) in the
interface filled up.

It is possible that your system was already "hung" and the FIFO overflow message
was merely an "interrupt level" admission that things had gone South.

The more normal indication is that either you have too many "fast" serial input
lines (like Trailblazer) modems on one interface or that your CPU isn't fast
enough for what you're asking of it.  If this is the case you can try changing
the arrangement of your serial lines or adding additional interaces to improve
the total FIFO capacity.

I used to see lots of these type of messages on my 785 - as many as a hundred
a day.  On a DMF-32, they caused no system level problems, just a bunch of
uucp retries.  On a DH11 some kind of driver bug leads to memory corruption
and daily crashes.

I haven't seen any of these messasges on my new 5810 w/DMB32...

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr at cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)