Re: Apple IIGS ROM listings and a general OS question

[mjmahon@aol.com (Michael J. Mahon)]

Mark Cummings wrote:

>Apple realized the problem of hardware specific bit handling much further
>back than GS/OS, and developed this principle with the IIe & ProDOS &
>interface cards. The Platinum IIe was stated as having a 95% (as best as I
>can remember) compatability with all software for the IIe. The ones that
>weren't compatable were mainly those that didn't follow the documented
>calls.

At the risk of straying afield, I note that the Platinum //e also introduced
a _hardware_ incompatibility with the earlier //'s.  They decided to put
0.1 mf capacitors across the pushbutton inputs (presumably in the interest
of reducing EMI or attenuating ESD), and wound up reducing their bandwidth
as input ports very substantially.  As a result, my game port clocks stopped
working until the pesky caps were excised.  Several hardware devices used
the PB inputs (such as ComputerEyes, IIRC) and these will also fail to work.

-michael

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