[rescue] A bit of Fun

Jonathan C. Patschke jp at celestrion.net
Tue Jun 17 16:03:30 CDT 2003

On Tue, 17 Jun 2003, Geoffrey S. Mendelson wrote:

> > The 80268 and 80386 both peeved me.  Both were good chances to fix
> > things, but they didn't.  But the 80286 was worse because you could
> > enter protected mode, but you couldn't leave it.  Thus, I never heard of
> > a single program that used 80286 protected mode, except OS2.
> A smart programer got around the problem. They set a bit to zero in memory
> and did a cpu reset. A real cpu reset would have left the bit unitialized,
> i.e. a one.

There was also that trick about triple-faulting the keyboard controller,
the details of which I can't seem to recall.  IIRC, you crashed the
keyboard controller, and the resulting reset would kick the CPU back
into real mode without a reboot.

Jonathan Patschke   )  "Leave your lawsuits at home.  I have guns."
Elgin, TX          (                      --"Kountry" Mike Lundgren

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