On Tue, 7 Sep 2004 08:31:33 +0100, Chris Bagnall <m0n0wall at minotaur dot cc> wrote:
> > >         I received a bunch of old PCs from a friend of mine
> > who runs a business. As part of the batch of PCs, I seem to have
> > acquired a POS 486 SX
> > > 25 MHz. The only thing I can think of that this will be
> > good for is to be a firewall.
> 
> I was under the impression that most of the linux and BSD kernels these days
> absolutely require a floating point unit. From my vague recollection of the
> 486-world, the SX is the version with the FPU missing (well, disabled at
> factory, but that's Intel for you). It might be well worth your while having
> a look at the system requirements for the kernel m0n0wall uses.
> 
> I know of people using linux/BSD firewalls on 486DX/33s, but never on an SX.


The M0N0WALL_GENERIC kernel file, used on the PC builds, includes: 
options 	MATH_EMULATE		#Support for x87 emulation

http://m0n0.ch/wall/downloads/M0N0WALL_GENERIC

This option provides floating point emulation in the kernel if it is
necessary.  So this will run on a 486 SX processor.
reference: http://mail-index.netbsd.org/port-i386/2000/10/23/0006.html

So yeah, it will run on an SX, but how fast is it really going to be. 
Might be enough for a low traffic site.  The Soekris boards that'll
push 17 Mb are only 486 133's.  A 486 SX with 64 MB RAM might be able
to push a T1 no problem.  (whether you can get 64 MB in the thing is
another question)

-Chris