Re: Utility for making disks?

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

Jon Bettencourt <jonINTERNETrelayCHAT@napaVALLEYnet.CLARInet> wrote:

> > .................................................... Or are you hoping
> > that you can put GS/OS on a disk and then boot it on the Mac?
> 
> Can you do that?

No, you can't.  (Unless you ran a IIgs emulator, such as Bernie to the
Rescue, which requires a Power Macintosh.  There is an older 8-bit Apple
II emulator called "II in a Mac" which should run on a Mac Plus.)

> Could the Mac use system software other than the MacOS?

There is a small set of alternatives, depending on which model you have.

Some that come to mind:

- At least two Linux variants for the Power Macintosh (MkLinux and
  LinuxPPC).  There may be a Linux variant for the 68030 and/or '040.
- Mac OS X Server (and soon Mac OS X), which are Unix/NextStep
  derivatives.  These require a Power Mac with a G3 processor (with
  eventual support for a G4).
- BeOS on some PowerMac models.
- A/UX (Apple's Unix variant) on some 68020/030/040 models.

A Mac model with a 68000 processor is probably not going to be able to
run anything except Mac OS.

> Or is it pretty hard-coded to using MacOS?

In general terms, yes, particularly with older models.  Recent Power Mac
models (Blue & White G3, G4, iMac, iBook and the latest Powerbooks) have
removed the Mac OS from the ROM, loading the relevant parts from disk
instead.  With these machines, it is feasible to have a Mac without
having to deal with anything about the traditional Mac OS.

The other operating systems I've mentioned above have to do a bit of
work behind the back of Mac OS to get themselves up and running.

> Does GS/OS use a System file?

Not as such.  IIgs System 5.0 and later include a "Sys.Resources" file,
which is approximately the equivalent of part of the Mac's "System"
file, but the system software of the two machines are arranged very
differently, and it would be difficult to do a detailed comparison.

One of the major differences is that the Mac gets most of its operating
system (particularly the file system support) from ROM, with patches
from the System file and extensions.  The toolbox is handled in the same
way.

By comparison, the IIgs ROM contains some of the toolbox, but absolutely
no operating system code.  The operating system is loaded entirely from
disk.  All that the ROM has is a bootstrap loader.  The parts of the
toolbox which are not in ROM are loaded on demand from separate toolset
files on disk.  There is also a file on disk which patches the ROM-based
toolsets to bring them up to the appropriate level for the system
software version you are running.

The IIgs did not have a Resource Manager until System 5.0, which means
that the evolutionary path of the Mac and IIgs operating systems were
quite different.

> Or do you need to rename some other GS/OS file to System?

No.  You can't use GS/OS to boot a Mac.

> If I know the location of the ROM, could I take the ROM out of a GS, stick
> it into a Mac, and use GS/OS there?

No.  The IIgs and Mac have completely different microprocessors, which
cannot directly execute code written for the other one.  (Ignoring the
issues of the rest of the computer architecture, which are also
significantly different.)

> What about the other way around? Could you take a Macintosh ROM, stick it
> into the GS, and have the GS work like a Mac?

No.  Same reason.

> I'm going to get a IIgs and a Mac Plus that I won on eBay soon. So if it
> won't work with recent Macs, could it work with a Mac Plus?... Probably
> not, since it doesn't have color.

Not with any Mac model, except in the limited case of running a IIgs
emulator on a Mac, but that is just a software application.  You still
need Mac OS.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand