Re: Another ProDOS ?

[pausch@saaf.se (Paul Schlyter)]

In article <a1%m6.50974$o85.290157@news-server.bigpond.net.au>,
Simon Biber <simon@basilisk2.cjb.net> wrote:
>> Just wondering if ProDOS is backward compatible with DOS 3.3. (ie will
>> it run DOS 3.3 files)
>
> ProDOS isn't backwards compatible. Programs written in Basic can usually
> work with few changes.
 
Only if they're written in Applesoft Basic.  Integer Basic programs
cannot run under ProDOS, unless....
 
> Binary programs will work only if they don't use DOS 3.3's internal
> functions and they don't mess up any of ProDOS's data structures.
> In practise, this means most DOS 3.3 programs won't run.
 
..and this offers a possibility to get Integer Basic programs to run
under ProDOS: compile them with an Integer Basic compiler, e.g. Mike
Laumer's "Flash!" (available for free from my website at
http://hotel04.ausys.se/pausch/apple2 -- the Flash! compiler itself
runs only on Apple DOS; not ProDOS).  This will of course only work
as long as the Integer Basic program doesn't attempt to do any disk
accesses.  Unfortunately, a Flash! compiled Integer Basic program
*will* mess up some data areas used by ProDOS -- but that doesn't
matter as long as the program is running since it doesn't attempt to
do disk accesses anyway.  But weird things may happen after program
termination, so the only secure way to terminate such a program is by
rebooting the computer.
 
-- 
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