Conference turris::digital_unix

9964.0. "RRD46 I/O hangs on 4100" by BIGUN::nessus.cao.dec.com::Mayne (Meanwhile, back on Earth...) Tue May 27 1997 23:15

We have a 4100, 4 CPUs, 1GB RAM, freshly installed UNIX 4.0B, RRD46.

I wrote a script that does nothing but cat files from the internal CD. Using 
iostat, we can see that there is a whole lot of I/O happening.

While that script is running, I start some other I/O on some other disks 
(they're striped together with LSM) by sorting some big file.

As soon as the other I/O starts, any I/O on the CD stops, and any processes 
that try to access the CD (e.g. the cat script above) hang. What seems to happen 
is that the CD will hang for a couple of minutes, do a small amount of I/O, hang 
for a couple of minutes, and so on. If I stop the other processes, the CD 
will not recover, and will stay like this (hanging, small amount of I/O, 
hanging, small amount of I/O, ...).

This happens with the CD on the internal SCSI, and with an external CD drive.

Any similar problems seen and fixed?

(NB this system has also been known to crash occasionally with a system 
uncorrectable machine check while running 3.2F, if that may be relevant. 4.0B 
has just been installed: no crashes yet.)

PJDM

Hi.
Did you found out what the problem was ?
I got a 4100 , Unix 4.0B,RRD46.
When customer tries to install Oracle the cd-rom hangs 1 min to 3-4 minutes
and then doing read's for ~ 20 sec and above repeats again.
I replaced rrd46 to rrd45 but new cd-rom behaves the same.

regards , Jonas Kjellberg , MCS Gothenburg
[Posted by WWW Notes gateway]

Apparently the 4100 has more blitzes against it than everything else put 
together.

One is that you can't have a KZPSA without anything attached to it.

Another is to upgrade the motherboard to rev B06 (from memory).

PJDM