[comp.sys.next] How to check SIMM

ty@reef.cis.ufl.edu (Tyng-Jing Yang) (02/08/91)

I know when RAM memory goes wrong we can switch to "Monitor mode" to
see which bank(socket) is died after reboot. I has one RAM died at
bank0, I switch bank0 with bank8 to keep machine up to post this message.

But I want to know is there any way to judge the rest RAMs are OK ?
How can I check it by electrical instrument ?

Thanks for your pointer

Jing

bb@reef.cis.ufl.edu (Brian Bartholomew) (02/08/91)

In article <TY.91Feb8004754@reef.cis.ufl.edu> ty@reef.cis.ufl.edu
(Tyng-Jing Yang) writes:

> But I want to know is there any way to judge the rest RAMs are OK ?
> How can I check it by electrical instrument ?

Uhh, you aren't going to like this, but pretty much you can't.  RAM
behavior is a complicated thing - unless the top is blown off, you
pretty much need to test it in-circuit under dynamic conditions to
tell anything useful.

What you need is a program that you run as root, that reads each and
every byte of memory in the system.  There might be one somewhere in
one of the monitors, I don't know.

A better test is to write a series of fancy test patterns to the RAM
that have been designed to catch the majority of most common hardware
failures.  However, this would have the undesirable effect of nuking
UNIX and all your programs.

I expect that there is such a program on the magical diagnostic kernal
that is only released to authorized service centers.  See if you can
talk it out of BusinessLand.  You may have to go to Jacksonville (yes,
this reference is only useful for North Floridians) to find a
BusinessLand.

--
"Any sufficiently advanced technology is indistinguishable from a rigged demo."
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