From owner-freebsd-hackers Sun Nov 16 00:23:08 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id AAA27685 for hackers-outgoing; Sun, 16 Nov 1997 00:23:08 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from csnet.cs.technion.ac.il (csnet.cs.technion.ac.il [132.68.32.7]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id AAA27673 for ; Sun, 16 Nov 1997 00:22:56 -0800 (PST) (envelope-from nadav@cs.technion.ac.il) Received: from csd.csa (csd [132.68.32.8]) by csnet.cs.technion.ac.il (8.6.11/8.6.10) with ESMTP id KAA21482; Sun, 16 Nov 1997 10:20:36 +0200 Received: from localhost by csd.csa (SMI-8.6/SMI-SVR4) id KAA15243; Sun, 16 Nov 1997 10:21:07 +0200 Date: Sun, 16 Nov 1997 10:21:07 +0200 (IST) From: Nadav Eiron X-Sender: nadav@csd To: "John S. Dyson" cc: Alex , tom@sdf.com, hackers@FreeBSD.ORG Subject: Re: 256Meg In-Reply-To: <199711160742.CAA12053@dyson.iquest.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Sun, 16 Nov 1997, John S. Dyson wrote: > Alex said: > > > > > > On Fri, 14 Nov 1997, Tom wrote: > > > > > > > > On Fri, 14 Nov 1997, dennis wrote: > > > > > > > Is there a maximum that FreeBSD can support? > > > > > > > > Dennis > > > > > > > > > What? Filesystems? RAM? Something else? > > > > > > RAM... no problem. I'm running two 256MB RAM servers now. > > > > Actually, there's a limit of 4GB or so of ram, on the 486 (if you call > > tha ta limit ;-) ), and AFAIK the P5, P6 and PII and clones as well. > > > Physically, the limit is 36Bits on a P6. It would require some mods to > the pmap layer, and maybe some enhancements to the upper level VM code. > One disadvantage with the extended 3 level translation mode is that > the PTE's become twice as large. I seriously doubt that we'll need that > on a P6, but on future Slot1/Slot2 processors, we might find that 4GB > is a real limit, and have to accomodate the modified PTD/PTE format. > > Imagine a processor that is perhaps 2X to 5X as fast as a P6, in a > multiprocessor config -- that would appear to be able to use more than the typical There is such a processor! It's called an Alpha! (sorry, couldn't resists). > upper end of 1GByte of memory, and even more than the normally addressable > 4Gbytes. > > I haven't given this alot of thought yet, but these issues are probably going > to be important in the medium-term future (approx 1yr.) > > -- > John > dyson@freebsd.org > jdyson@nc.com > Nadav