[comp.unix.ultrix] Loss of memory

hastings@sequoia.Berkeley.EDU (Mark Hastings) (09/02/89)

I am having a problem with Ultrix 3.1 on some new DecStation 3100s.

These machines have 24MB of RAM, and the hardware tests seem to find
and test all of it.  But when vmunix starts up, it can only "see" 16MB
of it.  The generic kernel also fails to see this memory.

Have I missed some simple configuration option, or might we have a hardware
problem (the DEC hardware and software support people are pointing fingers
at each other).

--Mark

hastings@walnut (Mark Hastings) (09/08/89)

In article <16787@pasteur.Berkeley.EDU> I wrote:
>I am having a problem with Ultrix 3.1 on some new DecStation 3100s.
>These machines have 24MB of RAM, and the hardware tests seem to find
>and test all of it.  But when vmunix starts up, it can only "see" 16MB
>of it.  The generic kernel also fails to see this memory.

It turns out that we had a hardware problem with some of the SIMMs.
I could have determined this right away if I had just known about the
"t ?" command from the console monitor.  Try it.  It is much different
from the "test" command -- much more in-depth and informative.

Unfortunately, the power-on memory diagnostics are not as rigorous,
since they didn't catch the problem.  I hope this saves other people
from banging their heads needlessly.

--Mark

graham@fuel.dec.com (kris graham) (09/08/89)

>It turns out that we had a hardware problem with some of the SIMMs.
>I could have determined this right away if I had just known about the
>"t ?" command from the console monitor.  Try it.  It is much different
>from the "test" command -- much more in-depth and informative.

"scsi pb"  is also very useful...it probes/reconfigures all scsi devices 
on-line.

Also, a "?" after a given command will normally tell you what options
are available with that command at the DECstation 3100 console.

BTW:  Replacing those SIMMs without any real expertise is not
           recommended.   The procedure is an art by itself ;-)


-- 
Christopher Graham          
Digital Equipment Corp            
Ultrix Resource Center                            
2 Penn Plaza