Date: Fri, 20 Jul 2001 18:28:26 -0700 From: Mike Smith <msmith@freebsd.org> To: janb@cs.utep.edu Cc: "Daniel C. Sobral" <daniel.sobral@tcoip.com.br>, Stefan Molnar <stefan@csudsu.com>, Marek Gorka <marek.gorka@tpi.pl>, freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.3 and 6G RAM Message-ID: <200107210128.f6L1SQd02267@mass.dis.org> In-Reply-To: Your message of "Fri, 20 Jul 2001 19:22:17 MDT." <Pine.GSO.4.30.0107201921460.3652-100000@gecko>
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> Even, when there is not more than 4BG RAM? Should a facility such as this
> not be disabled when not in use?
It's not trivial to "disable", unfortunately.
The core of the problem is that the 36-bit physical addresses have to be
stored in 64-bit variables, which are *much* slower than the 32-bit
variables we currently use. You can't adjust this at runtime, it has to
be a compile-time option.
There are other complications as well, which all add up to making this a
serious amount of work to deal with, and more to the point, one that
nobody has actually undertaken yet.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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