Xenix 286?

[Tony Duell]

>   Yup.  Because once in protected mode on the 286, you can't get out unless
> you reset the CPU.
> 
>   -spc (I think you could get out by tripple faulting ... )

Could you, in general. I think you can on the PC/AT, but I seem to recall 
a circuit that detects the odd state of the bus status lines if you get a 
triple fault, and then resets the CPU, or toggles a pin on the keyboard 
controller, or...

-tony