Testing PC Memory in DOS - HELP 
Author Message
 Testing PC Memory in DOS - HELP

I am trying to write a program to test the PC memory
(INTEL based). Can anyone help me out???
Best Regards,

      http://www.*-*-*.com/ ~soonhuat



Thu, 06 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP

Quote:

>I am trying to write a program to test the PC memory
>(INTEL based). Can anyone help me out???
>Best Regards,

When you boot your computer, the BIOS normally checks the memory.
Also, you would probably have to put the processor into protected
mode (or have a compiler that compiled protected mode programs).
There is an embedded system that I work with in which the BIOS
will continue making passes through memory until you load it up
with the terminal software or go into diagnostics mode.



group).

--
Craig

Manchester, NH
So what? I got my hands dirty to achieve our goal. -- Paul Mesken



Thu, 06 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP



Quote:
>I am trying to write a program to test the PC memory
>(INTEL based). Can anyone help me out???

This would be better posted in comp.os.msdos.programmer, the details you
are after will inevitable be platform specific.

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Thu, 06 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP

This is a PC specific topic and does not belong in this newsgroup.

Also, it is virtually impossible to write a memory test program in C,
anyway.  Under DOS, the code is part of the memory you are trying to test,
so the test would overwrite the code and send the machine to la-la land.
By the time you are executing C code, even if the code itself was not in
RAM, there is a stack and some of the variables used in the test must be in
RAM and would be trashed by the test itself.

The only way to write a complete, thorough memory test is to write it in
assembly language (where you can keep all variables in registers) and have
the code outside of the RAM you are testing (in the BIOS POST, for
example...).

So this is not a C question and does not belong in this newsgroup.



Quote:
> I am trying to write a program to test the PC memory
> (INTEL based). Can anyone help me out???
> Best Regards,

>      http://www.singnet.com.sg/~soonhuat



Fri, 07 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP



Quote:
>This is a PC specific topic and does not belong in this newsgroup.

>Also, it is virtually impossible to write a memory test program in C,
>anyway.  Under DOS, the code is part of the memory you are trying to test,
>so the test would overwrite the code and send the machine to la-la land.
>By the time you are executing C code, even if the code itself was not in
>RAM, there is a stack and some of the variables used in the test must be in
>RAM and would be trashed by the test itself.

>The only way to write a complete, thorough memory test is to write it in
>assembly language (where you can keep all variables in registers) and have
>the code outside of the RAM you are testing (in the BIOS POST, for
>example...).

>So this is not a C question and does not belong in this newsgroup.

Why not put the whole thing in L1/L2 cache?
Can you do that from assembler?

Turn off the x86 cache, and then use it as a store for your ASM program.
Then your code will not be blitzed >and< you don't have to overwrite the
BIOS.
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Sat, 08 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP

Quote:



>>This is a PC specific topic and does not belong in this newsgroup.

[some information from Jack Klein edited]

Quote:

>>So this is not a C question and does not belong in this newsgroup.
>Why not put the whole thing in L1/L2 cache?

Because there need not be L1/L2 cache on all machines where an
implementation of the C programming language is technically
possible.

Quote:
>Can you do that from assembler?

How is this related to the C prgramming language?

Quote:
>Turn off the x86 cache, and then use it as a store for your ASM program.

What if my machine does not have an x86 cache?

Kurt

--
| Kurt Watzka                             Phone : +49-89-2180-6254



Sat, 08 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP



        [snip]

Quote:
> Why not put the whole thing in L1/L2 cache?
> Can you do that from assembler?

> Turn off the x86 cache, and then use it as a store for your ASM program.
> Then your code will not be blitzed >and< you don't have to overwrite the
> BIOS.

Have done this in POST code in boot ROM (pseudo BIOS) on embedded systems,
using L1 cache to speed up running (literally) millions of iterations much
faster than from ROM, but you still can't do that from C, and most
protected mode OS's will trap and trash you if you try to modify CRO to
turn of cache.

--

Jack Klein

All views expressed in this message are mine,
and not necessarily that of my company or any
of our clients.



Sun, 09 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP



Quote:
>What if my machine does not have an x86 cache?

I'm sure they all (x86) do. I'm talking about L1 cache on CPU, not L2
cache on the motherboard.

--
Revised anti-spam in use : remove X to reply -
'Xnetbook' becomes 'netbook'

Anti-spam thermonuclear warheads cheap at only $300!



Sun, 09 Jan 2000 03:00:00 GMT  
 Testing PC Memory in DOS - HELP



Quote:


>>What if my machine does not have an x86 cache?
>I'm sure they all (x86) do. I'm talking about L1 cache on CPU, not L2
>cache on the motherboard.

An L1 cache was a feature Intel first introduced with the 486DX, so it
is far from true that all x86 machines have it.

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Sun, 09 Jan 2000 03:00:00 GMT  
 
 [ 9 post ] 

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