SUMMARY Faulty Memory ?

From: Victor Kolosov, by way of (
Date: Thu Jul 27 1995 - 13:29:43 CDT

Thanks to everyone who answered, my original post is on the bottom of this
Here are some simple solutions.

        Casper Dik <casper@Holland.Sun.COM>:

        you need to type "reset" before you type "test-memory".

        The OS does all kinds of things to the MMU that the PROM
        doesn't like.
=================================== (Mark R. Lemoine (508)-440-5126):

        At the "ok" prompt type in :

        setenv selftest-#megs 64
        (The 64 being how many megabytes of RAM you have installed)


        setenv diag-switch? true


        This will test your SCSI bus, as well as your RAM.
        If your RAM is bad, it'll be obvious, try switching
        the SIMMS around.

        To change things back to what they were :

        setenv selftest-#megs 1
        setenv diag-switch? false
====================================== (Robert L. Spence):

        I've used the following steps to test memory:

        ok setenv diag-switch? true
        ok reset

        The system will start to try and reboot, use Stop-A to interrupt
it. Now
        you can continue:

        ok test /memory
        ok test-memory

        The memory will be properly tested. When finished, return the
system to
        it's original state
        ok setenv diag-switch? false
        ok reset
        Ross Bennett <>

           I'm not 100% sure about this, but I think that when you halt
down your
        system, some of the "variables" used by the boot prom code will have
        been corrupted by the OS whilst it was running. This can cause memory
        address alignment faults which would cause the errors that you have
        been seeing.

        The best check of this would be to power down your system, power it
        back up and stop it with "L1-A" or "STOP-A" before it starts loading
        vmunix, then run your memory test (ie test /memory or whatever).
        This way the OS has not had a chance to do it's damage. If it gets
        through that test, then everything is ok with memory.

        Also, a better test for memory faults is to have your system running,
        as the OS will use the memory fairly thoroughly. If you don't get panics
        due to memory faults, then everything is ok. If you want to be more
        certain, run the memory test in sundiag for a few hours, this will slow
        your system down a bit, but it proves to be a pretty thorough test.


All of this helped cleared out my "problem" and let me ask you, where else
can you learn that OS corruptes the MMU that used by PROM, I guess only

Thank you very much.

>Hi Gurus !
>I have a Spark5/70 and everything seems to be working OK but if I halt the
>system and give it a test-memory I get:
> ok test-memory
> Testing Memory Instruction Access Exception
> ok
> ok test-memory
> Testing Memory Access Exception
> ok
>It was happening for a while and now it doesn't even give me that, all what
>I get:
> ok test-memory -or test /memory
> (get a blink of -Testing Memory- and that is all, the line is left
> ok

>Victor Kolosov.

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