Re: Woz GS differences

[dempson@actrix.gen.nz (David Empson)]

Shawn T Beattie <mustb5@uxa.ecn.bgu.edu> wrote:

> In article <5dnlcl$glg@darla.visi.com>,
> Nathan Mates <nathan@visi.com> wrote:
> 
> >Shawn T Beattie <mustb5@uxa.ecn.bgu.edu> wrote:
> >>I have a couple Woz GSs in my posession that I recently acquired
> >>from a local school.  Looking at the motherboard, I noticed that one of
> >>them has the //e-style keyboard connector and numeric keypad connector,
> >>well as the //e-style power supply connector, much like my GS-upgraded
> >
> >   Should be pretty much the same. Apparently, the ROM 3 lost the
> >//e power/keyboard connector compatability.
> 
> Except it is a ROM 0 --> ROM 1 IIGS that does not have the connectors.  My
> question is why some ROM 0/1 GS's have the connector and some don't.  Was
> it a supported feature of the ROM 0/1 GS or not?  Or was it a vestige of
> the GS upgrade for the //e's?

Quite simple: the original IIgs motherboard was designed to be used
either as a IIe-to-IIgs upgrade (in a IIe case, with IIe power supply
and keyboard) or as a shipped IIgs.

Apple appears to have populated several early motherboards with both
sets of connectors.  My early "Woz" IIgs didn't have the IIe connectors
installed, but I have heard of some that did have them.  Obviously, a
IIgs installed in a IIe case (the upgrade) would require the connectors.

I suspect Apple overestimated the popularity of the IIe-to-IIgs upgrade,
and ended up with a large stock of motherboards with the IIe connectors
installed.  Most of these ended up in "real" IIgses.

> And, is there any advantage/disadvantage to using the GS power supply
> connector over the //e connector?  Why did Apple bother to include both?

There is no point using a IIe power supply in a real IIgs case, because
there is nowhere to mount it.  The IIgs power supply sits above the
motherboard, while the IIe one sits alongside the motherboard (and is
screwed onto the case).

Any original IIgs motherboard is able to support the IIe power supply
and keyboard - you would just need to install the connectors if they are
not present already.

The ROM 3 (1 megabyte IIgs) removed support for the IIe upgrade.  The
keyboard micro and GLU dropped support for scanning the IIe keyboard
(but gained keyboard mouse, sticky keys and some additional support for
extended keyboards), and neither connector is provided.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand