Re: Goodbye GS/OS

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

Simon Williams <DON'Temail@luddite.ca> wrote:

> On Fri, 13 Dec 2002 21:51:47 GMT Andy McFadden <fadden@fadden.com> wrote:
> 
> Now here are a few further questions:
> 
> The Apple-Ctrl-Esc control panel doesn't seem to remember it's settings,
> which I presume is because the battery is shot... I'm willing to bet 
> that Wal-Mart doesn't stock these batteries, so is there any modern 
> equivalent that can be shoe-horned into place?

The same battery was used in several Mac models, and it may still be
available from an Apple dealer.

> Also, I noticed that A2 DeskTop won't run under ProDOS 2.x -- what are
> the big differences from 1.x ?

Nothing particularly major - it requires a 65C02 or better processor,
and has better support for SmartPort devices, allowing more than two
devices per slot with Apple SCSI cards, for example.

> And furthermore... (not sure if this is even a valid question) does the
> GS run P8 applications directly or is there some kind of emulator in
> ROM ???

The 65816 processor in the IIgs has an emulation mode in which it
behaves almost exactly like a 65C02 (with some extra instructions).
ProDOS-8 mostly runs in emulation mode, while GS/OS mostly runs in
native (16-bit) mode.

The IIgs memory layout, I/O hardware and firmware is designed to be
compatible with the IIe and IIc when running 8-bit software.  It changes
somewhat when running 16-bit software.

This "emulation" doesn't involve any performance penalties - it just
changes the behaviour of the CPU registers and instructions.  When
running ProDOS-8, the IIgs is almost 100% compatible with the IIe and
IIc, and is able to run faster (about 2.6 MHz instead of 1 MHz).

> Additionally, I'm using the composite colour monitor that looks like it
> belongs on the GS, but doesn't give a very satisfactory image... would
> a real GS (RGB?) monitor be a worthwhile investment? Would it make a 
> difference to P8 or just GS/OS ???

An RGB monitor works in all operating systems, and produces much better
colour quality than a composite monitor in all video modes.

The greatest benefit is gained when using the IIgs's super hi-res
grahpics mode (i.e. native IIgs graphical applications), but even the
traditional lo-res and hi-res grahpics modes look better.

-- 
David Empson
dempson@actrix.gen.nz