Re: The well-factored 386

John Bradford
2003-07-29T12:49:31Z

> > I didn't realise he was talking about an x86 emulator. I thought he
> > was analyzing real hardware.
> >
> > The one thing that made it on-topic for me was his quiet suggestion
> > that "forreal" mode interrupts are faster, and that it might, perhaps,
> > be possible to modify a Linux kernel to run in that mode - to take
> > advantage of the faster interrupts.
>
> That would have to be a kernel for very special use. The "forreal"
> mode has protection turned off. As far as I know, that
> means any user process can take over the cpu as if
> it was running in kernel mode.
>
> Perhaps useful for some embedded use with only a couple well-tested
> processes running. Still, a programming error could overwrite
> kernel memory instead of segfaulting.

Anything that's single user and non-networked isn't beyond the realms
of feasability - it would be useful for a games console, or high
performance graphics work.

It would be an interesting project, but what concerns me is how well
implemented these non-standard modes actually are. It's possible that
there are processors out there that don't work reliably with them, or
don't implement them at all.

John.