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Date:      Fri, 28 Apr 2006 07:40:06 -0400
From:      John Baldwin <jhb@freebsd.org>
To:        freebsd-chat@freebsd.org
Cc:        Francisco Reyes <lists@stringsutils.com>
Subject:   Re: What ever happened to Terasolutions?
Message-ID:  <200604280740.06963.jhb@freebsd.org>
In-Reply-To: <cone.1146179037.152247.60005.5001@35st-server.simplicato.com>
References:  <200604211034.k3LAY0TP096656@lurza.secnetix.de> <cone.1146179037.152247.60005.5001@35st-server.simplicato.com>

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On Thursday 27 April 2006 07:03 pm, Francisco Reyes wrote:
> Oliver Fromme writes:
> > (In other words:  PAE might enable you to use RAM >=3D 4 GB,
> > but your processes will still be limited to 32bit address
> > space.)
>
> Thanks for the pointer.
> That is a good reason to go AMD64 if one has apps which will require lots
> of RAM, although I can't think of any program I use ever needing 4GB+ for=
 a
> single program.

Well, part of the 4GB+ (1GB at least) is used for the kernel on i386, and
part of the space is reserved for stack, etc. such that your effective
mmap() limit is more like 2gb IIRC.  If a process wanted to mmap a file
bigger than 2gb (such as the backing store for a large SQL database) it
would have to include its own memory mapper to only mmap a window of
the file at a time, etc.  With a larger virtual address space it can
mmap the entire file without a problem.

=2D-=20
John Baldwin <jhb@FreeBSD.org> =A0<>< =A0http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" =A0=3D =A0http://www.FreeBSD.org



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