🚀 go-pugleaf

In article <1990Sep21.2...@herald.usask.ca>, petkau@herald.UUCP (Jeff Petkau) writes:
> In article <22...@opus.cs.mcgill.ca> pet...@opus.cs.mcgill.ca (Peter Deutsch) writes:
> |> >       Talking about how-to-turn-off-machine I forgot to say
> |> >       that BESM has a software feature to block power turnoff
> |> >       (I think it's a quite valuable idea, especially for Unix
> |> >       machines; what's about self-turning-on machines? ;-).
> |> 
> |> i have seen such a unix machine---the off switch just started a software
> |> routine that does synch and then turns off the power via software.
> 
> The Tandy 200 laptop did one better: it was not only turned off by software,
> but on again as well.

On the Epson Geneva, the power switch is managed by a little 4-bit processor
that's always running at about 100 KHz or so. It knows how to turn the Z80
on when you turn the power switch on and the Z80's already off, but if the
Z80s on the 4-bit just says "Excuse me, Mr. Z80, somebody turned the power
switch off". The Z80 has come back and tell the 4-bit processor to turn it
off.

You guessed it; if you're stuck in an infinite loop with interrupts disabled, 
you have to reset the machine before you can turn it off.
-- 
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Roger Ivie

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