Date: Wed, 18 Jul 2001 18:22:29 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.3 and 6G RAM Message-ID: <20010718182229.A86118@student.uu.se> In-Reply-To: <NFBBIJCJGLAFOKNCJHKHIEIBCGAA.jon@witchspace.com> References: <20010718105637.A97286@student.uu.se> <NFBBIJCJGLAFOKNCJHKHIEIBCGAA.jon@witchspace.com>
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On Wed, Jul 18, 2001 at 05:04:45PM +0100, Jonathan Belson wrote: > Hiya > > > > i have an intel 4400 platform equipped with 4 xeon processors and 6G ram. > > > the mainboard is based on the ServerWorks ServerSet II HE chipset (by > > > intel), which supports up to 16G RAM (or 32G, i'm not sure at the moment). > > > > > > i have installed FreeBSD 4.3-STABLE. > > > > > > unfortunately, the system seems unable to work with this amount of ram. > > > > FreeBSD does not support more than 4G RAM (at least not on x86, I > > don't know about Alpha). > > My suggestion would be to remove the extra 2G RAM from the machine and > > see if things work better then. (FreeBSD will not be able to use it > > anyway so you don't lose anything by removing it.) > > Dumb question: by my calculations, a 32bit address register can only > address 2**32 bytes of memory, ie. 4GB. Is it possible for your > average P3/Athlon to addres more than this? Does it use banking/ > MMU tricks? > Not a dumb question but yes, and yes. Modern x86 CPUs can address more than 4 GB of physical RAM. I think this was introduced with the Pentium Pro but I am not certain. Yes, it uses MMU tricks to do it. Note that even though the physical memory may be more than 4 GB the address space of a single process is still only 32 bits so a single process still cannot address more than 4 GB of RAM. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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