hi,

Looked in mz and pegasos book for recommended ram for peg2
and the largest ram checked and tested was crucial 1GB ct12864z40b-16tfy and also other configurations with 2 sticks they should be same size and brand. so i got a pack of twin sticks 2x1gb (ct12864z40b)
but pegasos/mos only sees 1.56GB and trance goes apeshit with its cpu
usage and locks machine. any tips ? (except only using 1 stick :) )

use only one stick ;-)

A couple of questions: did you try swapping the 2 memory sticks? Do they work individually?

Check that the chips are really equivalent as speed mismatches generally cause severe damages (not only in the Pegasos world). If you can plug them into a PC, I would try memtest86 too. You may have a defective unit.

My cent worth ;-)
Olivier

it wouldn't be a problem here as he uses some twin sticks, same modules.

MorphOS won't report more than 1,5Gb (maybe it will be fixed in 2.0 ?)

Check under Linux, you should see your 2Gb.

IIRC i was also using 2Gb (2x1Gb) and had lots of compilation errors under Gentoo, everything went fine with only one stick (tried with both).

it's only my curiosity... but does PegII support DDR-266 PC2100 ECC mem sticks?

They will work, but they are slower than standard RAM, as they have higher latencies for for reliability, on top of the fact that PC3200 RAM would run at further lower latencies at 266MHz.

The ECC feature is not used as the processor exceptions are not hooked up (the same as 36-bit addressing is not hooked up).

However the Marvell Northbridge can count ECC exceptions and you can gain statistics on it. You are free to reverse engineer how to do this on pain of voiding your warranty when you fry your board.

If you manage to install more than 2GB of RAM and coerce the firmware to configure it, too, then you can encourage the Marvell Northbridge to map it in the 36-bit address space and access it using the DMA controller. Again, on pain of voiding warranty :)

Both are documented somewhere in code online (the DMA controller has an old Linux driver by a Philip Something?) if you search hard enough.

btw, you are lucky, i've just now bought a 1GB stick and doesn't work on peg2....

I bought an 512MB RAM module a few weeks ago, and it did not work. It's a 400Mhz one. Today I put it in an old P4 and took a 333Mhz 512 MB module home, put it into my Pegasos, and it works fine. So I have now a total of 768MB of RAM in my Peg.

Maybe you will have more luck with an older module? Just a guess...

mmh, i've just bought a 512MB pc2700 (samsung) for our peg2, it works. I cannot add the other 256MB 'cause slot2 seems to be broken :/

Finally I downgraded to 512MB, as using both of the modules worked for most of the time, even for compiles, but crashed the openSUSE installer all the time. And I don't want to take it out for all the installs and put it back for the rest, as sometimes I do installs more than once a day :-)

We shipped many ODW with 1GB in each slot. 2GB works and is still working today in many instances.

R&B :)

Caveat: you may need paired RAM and you may need a 2B5 revision board for it to work. We used Kingston kit ram with blue heatspreaders.. I think KHX3200AK2/2G is the right model.

i've tried a bit again.

Pegasos2 does accept both low or high density mem modules but never exceeding 512MB per rank...

then a maximum of 512MB module x slot if high density type or 1024MB module x slot if low density one.

but our pegasos2 (fw version 1.2 20040810112413) seems to have some problems and great instability using more than 512MB then we'll move this machine only to test peg2 iso boot kernel.

FWIW, I'm using exactly one of these (sorry, it's a greek site):

http://www.e-shop.gr/show_per.phtml?id=PER.552054

For quite some time with absolutely no problems. Using both for a total of 2GB didn't work, but one of these is fine. I still have the 2nd here as a spare but no machine to use it :)