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Re: Do I need 64Bit if RAM is more than 4 GB?

On Wed, 2004-09-08 at 23:49 +0200, Mattias Wadenstein wrote:
> On Wed, 8 Sep 2004, Lennart Sorensen wrote:
> > On Wed, Sep 08, 2004 at 04:09:59PM -0500, Ron Johnson wrote:
> Ehm. There is no 64-bit version of the POWER ISA, it was 
> extended/fixed/replaced by the PowerPC ISA which was designed with 32 and 
> 64 bit implementations to begin with (I think). POWER3 is a ppc64 
> implementation selling under the POWER brand, not a 64-bit POWER 
> implementation.
> Before the POWER3 (and other ppc64 implementations), the SMP rs6000 
> machines where 32-bit ppcs and had address limitations which meant that 
> the maximum ammount of memory supported was around 3-3.5 gigs. This is in 
> place even for the ppc smp sp2 node called "silver", which I happen to run 
> a couple of for ftp.se.debian.org. These were the high-end computational 
> resources that were replaced by the POWER3, and couldn't handle more that 
> 4 gigs of ram.
> The IBM sales manuals are around and pretty good at telling you exactly 
> what hardware combinations are/were supported, I think you'll notice that 
> the support for more than 4GB came at the launch of the POWER3 (or the 
> RS64(?) chip, another ppc64 implementation used by ibm for the commercial 
> computing segment rather than technical computing).

Well, I guess that answers the original question regarding whether
POWER32 could handle more than 4GB...

Ron Johnson, Jr.
Jefferson, LA USA
PGP Key ID 8834C06B

"He was about as useful in a crisis as a sheep."
Dorothy Eden

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