Re: Something interesting...

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

Obsbedia2 <obsbedia2@aol.com> wrote:

> This is news to me.... I guess I thought ProDOS after 1.9 was for the GS only.
> In other words, I thought it was a 16 bit version for the 65C816 chip.

Nope.  ProDOS-8 2.0.x uses 65C02 instructions, so it requires a 65C02,
65802 or 65816 processor, and won't work on the original 6502.

This means that it needs a IIgs, IIc or enhanced IIe (or an earlier
machine with a 65C02 or 65802 processor installed, either a normal one
or an accelerator like a Zip Chip).

> I know I have a lot of research to do, with everyones questions. And the
> first thing is to determine which versions of ProDOS and GS/OS my firmware
> will support.
> 
> Do you no a good sites that spell out the version history of Apple II OS's?

Apple published a technical note which explains the changes in ProDOS-8
versions up to 2.0.1 (TN.PDOS.023: ProDOS 8 Changes and Minutia).

There isn't likely to be much in there which is relevant to drivers,
other than the added SmartPort support in 2.0.x (allowing more than two
units per slot), and the support for four units in slot 5 with 1.2 and
later.

GS/OS support is a non-issue: as long as your firmware complies with the
SmartPort interface standard (or at least the ProDOS standard) then
GS/OS will support it.  You can get much better performance by writing a
native GS/OS driver (and there aren't any significant changes in driver
support between System 4.0 and 6.0.1).

ProDOS-16 (IIgs System 3.2 and earlier) is somewhat more limited, but it
should at least support a ProDOS block driver in firmware.

-- 
David Empson
dempson@actrix.gen.nz