Re: Apple IIe + ProDOS = Headache

[David Wilson <david@uow.edu.au>]

Jeff Blakeney <CUTjblakeney@sympatico.ca> writes:
>Ewww, ick.  I don't think I even have a copy of ProDOS v1.3 and I
>didn't get an enhanced IIe until after I had a IIgs so I guess I never
>learned that tidbit properly because it never affect me.  Thanks for
>the description of the bug.

Here is the description as published in Open-Apple v3 n2 March 1987 page 3.12:

 ProDOS 8, version 1.3, released to developers in mid-January and mentioned
 here last month, mistakenly includes a BRA (branch always) machine language
 instruction in a critical piece of code. This is a significant problem,
 because BRA isn't supported by the original 6502 microprocessor. Consequently,
 this version of ProDOS causes bad things to happen when run on Apple II-Pluses
 and unenhanced IIes. If you BLOAD PRODOS,TSYS,A$2000, then the bad instruction
 appears at $4CCD. A BEQ (branch on equal) would work just as well here, so you
 can fix things with a POKE 19661,240 and a BSAVE PRODOS,TSYS,A$2000.

I personally see no reason for anyone to be running any versions of ProDOS 8
other than v1.9 on 6502 equipped Apple IIs and v2.0.3 on 65C02 equipped
systems. This way you get all the known bug fixes. 
-- 
David Wilson  School of IT & CS, Uni of Wollongong, Australia