Cyrix 6x86 - wierd problem

Nigel Metheringham (
Fri, 13 Dec 1996 11:45:14 +0000

I have a set of boxes out (ie off site) that are based on a Cyrix 6x86
processor. One of these has a very strange reproducable problem on boot
up, the others to date do not. However some of the boxes have the
occaisional glitches with perl scripts!

The reproducable problem is a script which runs during boot up. The
script is basically

sed -f /etc/config/NETWORK.sed <<END_OF_DATA
[several lines of stuff]

exit 0

This script, and several extremely similar (ie different only in the data
lines) scripts are called during boot to build a series of config files.
The control file which runs these checkes the exit status and whether the
generated output is zero length. This works perfectly on all other
machines, and on this machine when the scripts are run at any time other
than during the boot sequence.

However if run from the rc files on boot, the script consistantly manages
to produce a zero length output (which for some reason is not picked up by
the supervisory script).

One of the other machines has shown up odd perl problems - script fails to
compile, but then works OK.

The machines are all running (at present) 2.0.26 with serial console,
cyrix, syn bomb and minor ip masquerading patches. A similar box with
intel processor seems immune to these problems.
The Cyrix patch is based on Mike Jardis' 2.1.x #3 patch with minor
reworking for 2.0.x - which only affects VSPM which I actually have
disabled (to try and fix these problems).

One other thing I noticed when putting this message together is that the
/proc/cpuinfo bogomips fields are different for the box showing this fault
and the other boxes:-
processor : 0
cpu : 586
model : 6x86 2x Core/Bus Clock
vendor_id : CyrixInstead
stepping : 1 rev 5
fdiv_bug : no
hlt_bug : no
fpu : yes
fpu_exception : yes
cpuid : yes
wp : yes
flags : fpu
bogomips : 52.33

the OK box reads:-
bogomips : 119.60

Any clues would be greatfully received....


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