Duane Rettig  <duane@franz.com> wrote:
+---------------
| >Frode Vatvedt Fjeld <frodef@acm.org> writes:
| > Finally, assuming a 4GB address-space (see below),
|
| Minor correction: most current 32-bit operating systems only give you
| 2 Gb of usable space, though a couple of them can give you 3 Gb.
+---------------

Yup. For example, see <URL:http://oss.sgi.com/projects/bigmem/> for the
the SGI "bigmem" patch for Linux, which supports up to 3.8 GB physical
memory on IA-32, providing up to 3GB user space.  [That URL also contains
a discussion of the performance costs of "bigmem" on IA32, including such
things as forcing drivers to use "bounce buffers" & bcopy'ing to access
certain areas of memory.]

+---------------
| > So I'm simply ignoring 64-bit architectures (for now).
|
| By the time you get to the point where you are ready to introduce
| your system to the world, even at worst case for the already late
| IA-64, the new 64-bit operating systems will be out and will fast
| become standard, and you will have latched on to the tail end of
| this 32-bit prevalence.
+---------------

Confirming signs:

1. We (and others) have already publicly demonstrated large applications
   (e.g., clustered HPC codes) running under IA-64 Linux.

2. Porting of Linux to AMD's "Sledgehammer" (64-bit extension to Athlon)
   has already started. <URL:http://www.x86-64.org/>
   <URL:http://www.suse.com/suse/news/PressReleases/x86_64.html>
   <URL:http://news.cnet.com/news/0-1003-200-2523097.html>

So from what I can see, we'll be starting down the "tail end" of IA-32
by next summer!


-Rob

-----
Rob Warnock, 41L-955		rpw3@sgi.com
Applied Networking		http://reality.sgi.com/rpw3/
Silicon Graphics, Inc.		Phone: 650-933-1673
1600 Amphitheatre Pkwy.		PP-ASEL-IA
Mountain View, CA  94043