Re: 200 apple II clones confirmed

["David Wilson" <mcs6502@gmail.com>]

Michael J. Mahon wrote:
> Eric wrote:
> > When I was in Korea 1984-1986 I saw dozens of locally-made clones. They
> > were all variations of the II+, and some of them used 64K RAM chips. I
> > think they all used off-the-shelf parts, which is why it was harder for
> > them to clone the IIe (I didn't see any IIe clones while I was there).
>
> Within Apple, the use of ASICs in the //e was seen as a powerful
> deterrent to the cloning that had plagued the ][ and ][+.

It didn't work...

My first Apple II compatible computer was the MPF-III (model 312) which
is a IIe clone made from LSTTL and two PAL chips (plus a
microcontroller in the detached keyboard). The MPF-III model 327 was
subsequently released and it did use MMU and IOU ASICs.

The model 312 was only about 95% software compatible with the IIe.
Replacing the ROMs with genuine IIe firmware bought it up to 99% with
the following differences:

* 2KB aux RAM confused ProDOS which was expecting 0KB, 1KB or 64KB only
* The AUXZP softswitch was not implemented (as there was no Aux slot).

I built a 64KB aux ram daughtercard and replaced one PAL with a larger
GAL with AUXZP support added giving me a superset of the IIe.