Re: SIMM 32 MB :-(

From: Petr Stehlik <pstehlik_at_zln.cz>
Date: Wed, 25 Feb 1998 10:12:40 +0100

Hi,


>> you surely remember me asking if 32 MB EDO SIMM will work in AB40. Since
I
>> got six positive responses, I went and bought the SIMM. I installed it
and
>> turned on my computer. Doug's TK 5.07 found both SIMMs, performed mem
test
>> and announced 48 MB of FastRAM to the TOS.
>
>Cool. What does Doug's mem test do?

That's interesting: regardless of position of the SIMMs it shows these
lines:

================
================
==============

so it looks like last 2 MB are missing :-O But the ToolKit always sets the
TOS to 48 MB of memory. Perhaps a bug in TK 5.07? Doug???

>> Interesting is that Linux bootstrap finds 48 MB in bank 1! That's
strange,
>> since banks are 32 MB max.
>
>Says who? :-)
>
>I have seen figures for 128MB AB040s but I don't know of anyone testing it.

I've seen the figures as well, but Douglas came with different opinion when
he was testing and developing TK 1.x

>Try the SIM in a PC and test it. Should be the esiest way to find out where
the
>problem is.

I would do that if it was possible. There are only Pentiums in our office
and all have 4x16 MB. I am missing the second 32 MB to be able to test it
:-(

>Does the errors indicate that a address line is broken? Should be easy to
see
>if you look at which address are broken.

The TTRAMTST was writting $ff to every address and then reading it back. The
report was like this:

$28b8ff7 - read $fb
$28b8ffb - read $fb
$28b8fff - read $fb

so it looks like one of the 16 chips is partially broken (because the error
repeats every 4th byte address and always one bit is missing).

>Make a program which puts a "walking" 1 on the data bus. Just take a

sounds like you know how a memory test should be written. Go ahead and write
it, please :)

>If this does not work I guess you have to make a patch to "remove" the
>faulty addresses. :-\

I don't like it. Perhaps Doug could have a look at the TK - it detected some
problems while testing the memory (see the missing '==') but forgot to
update system variables, I think.

>I do think the problem is with the SIM.....

I strongly hope so. Otherwise I lost another 100 DM and mainly my confidence
in AB40 :-((

Petr
Received on on. feb. 25 1998 - 11:20:00 CET