Subject: Re: Memory: Parity vs ECC?
To: Pavel Cahyna <pavel.cahyna@st.ms.mff.cuni.cz>
From: Michael Kukat <michael@bsdfans.org>
List: port-alpha
Date: 12/30/2002 11:32:07
Hi !

On Mon, 30 Dec 2002, Pavel Cahyna wrote:
> > In any case, it is a lot easier to get x36 memory SIMMs than x33.
> > High-end PC's greatly outnumbered Sun workstations of that vintage.
> >
> Do you mean that Sparcs typically use x33 SIMMs, while PC servers
> typically x36? That's an interesting information on its own. Can x36
> SIMMs be used in Sparcs?

I think, Suns don't use 33bit in general, i didn't try this, but i think, the
SparcStation ELC/SLC needs 33 bits, other machines may need 36 bits. Alphas
sometimes need 33 bits (AlphaStation 200?), sometimes 36 bits (Multia?
AXPpci33?)

I never tried in detail, but as a rule of thumb:

33 bits are hard to get. 36 bits are easier to get.
36 bits run nearly everywhere, except some rare machines needing 40 bits.
I'm using the standard 36 bit modules in Alpha, Sparc, IBM RS/6k, SGI and lots
more here.

HP Modules (9000/700 series and some newer 400s) are also 36 bits, but be
careful here, they just look like PS/2 but have a slightly different pinout and
maybe even some magic interleave or so. At least some data bits are wired
different.

...Michael

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