Date: Thu, 02 Aug 2001 11:54:25 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: Kenneth Wayne Culver <culverk@wam.umd.edu> Cc: Rik van Riel <riel@conectiva.com.br>, Terry Lambert <tlambert2@mindspring.com>, craig <craiglei@pasia.com.cn>, freebsd-hackers@FreeBSD.org Subject: Re: How to visit physical memory above 4G? Message-ID: <XFMail.010802115425.jhb@FreeBSD.org> In-Reply-To: <Pine.GSO.4.21.0108021436250.20844-100000@rac2.wam.umd.edu>
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On 02-Aug-01 Kenneth Wayne Culver wrote: > BUT, don't the motherboards also have to support this? And isn't it only > supported through some wierd segmentation thing? > > KEn The motherboards do, yes, and they have. It's not segmentation. It's only in the paging that this is done. Go to developer.intel.com and get the IA32 manuals, specifially volume 3: system programming, then look for 'Physical Address Extensions' and start reading. > On Thu, 2 Aug 2001, John Baldwin wrote: > >> >> On 02-Aug-01 Kenneth Wayne Culver wrote: >> > Also, the PIII CAN'T natively support more than 4GB of ram. If a >> > particular PIII motherboard supports this, then it's using some kind of >> > wierd chipset that allows this to happen. 4GB is the limit with a 32 bit >> > chip I believe; and the PIII is a 32-bit chip. >> > >> > Ken >> >> Go look at some Intel docs. P6 chips since the Pentium Pro (yes, before >> Pentium II) have supported PAE which allows for a 36-bit physical address. >> >> -- >> >> John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ >> PGP Key: http://www.baldwin.cx/~john/pgpkey.asc >> "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ >> > -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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