Re: >64MB RAM problems, why?

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Wed Apr 05 2000 - 15:49:41 EST


On Wed, 5 Apr 2000, Bob Lorenzini wrote:

>
>
> On Wed, 5 Apr 2000, Richard B. Johnson wrote:
>
> > Upon startup Win/NT writes to (most) all RAM above 1 Megabyte, then reads
> > it back. You can watch this with a logic analyzer. It does this with
> > parity-check disabled and, FYI, never enables it after.
> >
>
> Your saying parity memory is totally useless on Win/NT?
>
> Bob

Well. It may be useless on most modern RAM. I haven't seen any
RAM, rated at 100MHz or higher (P100) that even has the extra bit.

The last time I saw parity RAM was the 65 ns stuff. PC RAM Vendors,
when questioned, have responded; "It's now built-in...". Which
translated means; "Missing...".

None of the PC stuff ever corrected RAM errors with a CRC, even though
there was some RAM called "ECC" RAM which implied that it did. The
ECC RAM just accumulated bits from multiple columns to save parity
bits. It still hit MNI when it detected an error. Alpha and Suns
have (or had the last time I looked), real ECC RAM.

Cheers,
Dick Johnson

Penguin : Linux version 2.3.41 on an i686 machine (800.63 BogoMips).

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