Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 15 May 2000 15:43:08 -0700
From:      David Greenman <dg@root.com>
To:        "Erin" <kahn@deadbbs.com>
Cc:        "'Brian'" <bellefso@execpc.com>, "'Freebsd Questions'" <freebsd-questions@FreeBSD.ORG>
Subject:   Re: Max Physical Memory 
Message-ID:  <200005152243.PAA10446@implode.root.com>
In-Reply-To: Your message of "Mon, 15 May 2000 15:37:08 PDT." <004301bfbebe$1acefe20$8914820a@EndUser.sdccd.cc.ca.us> 

next in thread | previous in thread | raw e-mail | index | archive | help
>>    The maximum that FreeBSD supports now and in the medium 
>> term future on the
>> x86 platform is 4GB. Going beyond that requires majors 
>> changes to device drives and the VM system.
>
>Does the 32bit architecture partially responsible for the
>4GB limit? If not, when do you forcast the changes to hit
>the FreeBSD OS?

   Yes, the system was written to assume 32bit physical address space. The
page table format changes when using the extended addressing and device drives
have to be rewritten to do 64bit PCI address cycles.
   Some of the device driver changes are in the works (I recall Justin talking
about extended address bits in the ahc driver, for example), but the VM system
changes are probably a ways off and may never happen since the 64bit Itanium
will eventually replace x86 on the high end, thus reducing the need to scale
that far with x86.

-DG

David Greenman
Co-founder, The FreeBSD Project - http://www.freebsd.org
Creator of high-performance Internet servers - http://www.terasolutions.com
Pave the road of life with opportunities.


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200005152243.PAA10446>