Hi!

> > > I think there were 486s with up to 256MB, which would still qualify as barely
> > > usable for a minimal desktop, or as comfortable for a deeply embedded
> > > system. The main limit was apparently the cacheable RAM, which is limited
> > > by the amount of L2 cache -- you needed a rare 1MB of external L2-cache to
> > > have 256MB of cached RAM, while more common 256KB of cache would
> > > be good for 64MB. Vortex86SX has no FPU or L2 cache at all, but supports
> > > 256MB of DDR2.
> >
> > There are also some newer (well less than 30 year old) cpus that are
> 
> (less than 10 years actually)
> 
> > basically 486 but have a few extra instructions - probably just cpuid
> > and (IIRC) rdtsc.
> > Designed for low power embedded use they won't ever have been suitable
> > for a desktop - but are probably fast enough for some uses.
> > I'm not sure how much keeping 486 support actually costs, 386 was a
> > PITA - but the 486 fixed most of those issues.
> 
> Right, we have "last of mohicans" (to date) Intel Quark family of CPUs
> (486 core + few i586 features).
> This is for the embedded world and probably not for powerful use.

We have open-hardware implementation for 486, AFAICT, thanks to MISTer
project. I'm not aware of open 586 core.

Being able to run recent Linux on open hardware sounds fun.
									Pavel
-- 
http://www.livejournal.com/~pavelmachek