[johnnym]

So, I had another go at this and got new information:

Though the six 256 MiB PC133 registered/buffered ECC modules (two of each of the Compaq/HP related modules from the last post) I had installed in my PWS 500au work through POST, OS boot and "light" testing (i.e. 7za b -md=2m), they unfortunately seem to fail when using more memory (i.e. bigger dictionaries) during 7za b runs. When this happens, the system freezes and becomes unresponsive.

This also happens when testing them separately (meaning two identical modules) in SRM with the memtest tool (see the SRM console reference, page 97 and following for details and usage), which hence might be a good and quick way to determine any "good" modules for a PWS.

So these three (or two when considering the part number or specification) module types are no good for the PWS.

The IBM and CENTON ones though do work in SRM's memtest and also work during 7za b runs unless you hit a situation where the Linux kernel (6.3.x) is not able to handle a paging request.

Testing in SRM could be done like that (example from testing the Centon modules):

Code:

>>>show mem


Memory Size = 512Mb

Bank      Size/Sets   Base Addr
------    ----------  ---------
   0        512Mb      00000000


BCache Size = 2Mb

Tested Memory =  512Mbytes

>>>date; memtest -bs 100000 -rb -p 1 && echo "OK"; date
10:58:11  June 23, 2023
OK
10:58:38  June 23, 2023

>>>date; memtest -bs 100000 -rb -p 10 && echo "OK"; date
10:59:34  June 23, 2023
OK
11:02:01  June 23, 2023

First check that all memory was detected, then do a single pass test which should take less than 30 seconds, then run a multipass test.

So I'm now down to 1 GiB at the moment using the two IBM (PC100) and the two CENTON (PC133) registered/buffered ECC modules.

I also tested the unbuffered ECC modules from my earlier post in SRM and can confirm that the machine survives the testing with them.