Re: Can multiple OS's reside on the same hard drive?

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

In article <robb-2006960831400001@129.15.41.148>,
Robb Andrew Young <robb@uoknor.edu> wrote:
> On my IIgs, is it possible to have System 5 and System 6 on a hard drive
> at the same time, "blessing" the one I want to boot with?

Yes, but there is no simple facility built into the system software to
allow this.  There may be a program which can simplify the task for
you, but the basic idea is as follows:

- Install System 5.0.2 (or 5.0.4).
- Rename the PRODOS file to PRODOS.5 and the SYSTEM folder to SYSTEM.5.
- Also rename BASIC.LAUNCHER to something else temporarily.
- Install System 6.0.1. (This will replace BASIC.SYSTEM with the latest
  version).
- Rename BASIC.LAUNCHER back to its original name.

You now have a System 6 installation.  If you want to boot System 5,
then get into ProDOS-8, and rename all the affected files:

1. Rename PRODOS to PRODOS.6
2. Rename SYSTEM to SYSTEM.6
3. Rename PRODOS.5 to PRODOS
4. Rename SYSTEM.5 to SYSTEM

You now have a bootable System 5 installation.  To get back to System
6, just reverse the rename operations.

You could even write a simple BASIC program which does this.  I seem
to recall doing this myself (with System 4 and 5, probably) - identify
which system is currently active, and then do the appropriate set of
renames.

It probably isn't safe to do this while GS/OS is active, because some
files are yanked out from under the system software when you rename
the system folder, but launching P8 from within GS/OS and doing it
then is fine, as long as you reboot the computer rather than
attempting to quit back to GS/OS.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand