Subject: Re: Memory: Parity vs ECC?
To: Matt Thomas <>
From: Nathan J. Williams <>
List: port-alpha
Date: 12/27/2002 22:01:44
Matt Thomas <> writes:

> At 02:35 PM 12/27/2002, wrote:
> >Say, if I'm trying to buy ECC memory for my AlphaStation 200, will any
> >1234x36 SIMM work? (Well, 64MB or smaller I guess.)
> >
> >I thought non-parity was FOOx32, parity FOOx33, and ECC FOOx36. Is
> >that not correct? It's pretty easy to find "parity" FOOx36 memory,
> >but I really want ECC. What's the scoop?
> You want x36 FPM since the AS200 uses two bank as once so each 64bit
> access has 8bits of parity which the APECS chipsets uses for ECC.

My manuals are at home and I'm behind a slow net connection, but I'm
reasonably certain that the AS200 memory system does *not* need or use
ECC; I think it only needs 33-bit memory. The documentation of the
machine check errors generated on that system is full of notations
like: "37: ECC error. Cannot happen, hardware does not have ECC

        - Nathan