On Mon, Jan 11, 2021 at 11:55 AM David Laight <david.lai...@aculab.com> wrote: > From: Arnd Bergmann > > Sent: 09 January 2021 21:53 > > > > On Sat, Jan 9, 2021 at 6:56 AM Willy Tarreau <w...@1wt.eu> wrote: > > > > > > On Fri, Jan 08, 2021 at 11:55:06PM +0100, Arnd Bergmann wrote: > > > > * 80486SX/DX: 80386 CPUs were dropped in 2012, and there are > > > > indications that 486 have no users either on recent kernels. > > > > There is still the Vortex86 family of SoCs, and the oldest of those > > > > were > > > > 486SX-class, but all the modern ones are 586-class. > > > > > > These also are the last generation of fanless x86 boards with 100% > > > compatible > > > controllers, that some people have probably kept around because these > > > don't > > > age much and have plenty of connectivity. I've used an old one a few times > > > to plug in an old floppy drive, ISA SCSI controllers to access an old tape > > > drive and a few such things. That doesn't mean that it's a good > > > justification > > > not to remove them, what I rather mean is that *if* there is no benefit > > > in dropping them maybe we can keep them. On the other hand, good luck for > > > running a modern OS on these, when 16MB-32MB RAM was about the maximum > > > that > > > was commonly found by then (though if people kept them around that's > > > probably > > > because they were well equipped, like that 64MB 386DX I'm having :-)). > > > > 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. -- With Best Regards, Andy Shevchenko
