//c+ switch settings, QWERTY/Dvorak (was Re: IIc+ mouse `A+ Little

From: Sellam Ismail <foo_at_siconic.com>
Date: Fri Aug 30 15:32:00 2002

On Fri, 30 Aug 2002, Patrick Finnegan wrote:

> OK, now I've never gotten to play with one of these. How exactly does it
> hijack the system like this? Does it use some software trick to halt the
> motherboard proc, or is there a bus line that lets it grab control, like
> the /LOCK line* that's on an 80x86?

Slot 3 on the Apple //e bus is a special slot. Normally, if you have an
80-column card plugged into the special auxiliary slot, you can't use slot
3 for anything else, but the TransWarp is an exception. It was designed
to co-reside with the 80-column card without conflicting, and so takes
advantage of a completely empty (and otherwise useless) slot.

I don't know the actual technical process since I never looked into it,
but in essence I imagine what the TransWarp does is pulls some signal to
let the bus know that it is in control and then takes over that way. I
should dig out my copy of the //e technical reference manual to find out
exactly what's going on.

I imagine it could work in any slot, but I haven't read the documentation
in years, don't know exactly where it is, and don't have the time to
experiment right now :(

Sellam Ismail Vintage Computer Festival
International Man of Intrigue and Danger http://www.vintage.org

 * Old computing resources for business and academia at www.VintageTech.com *
Received on Fri Aug 30 2002 - 15:32:00 BST

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