I think that Apple has old system software available
from their ftp site
(my school's public fileserver has versions up through 7.1, therefore
those systems are probably freely available from Apple). You would
probably want to download disk images for system version 6.0.5 or 6.0.8
(there should be four 800k disks), make floppies out of them, then boot
with the "System Tools" disk and run the installer. It will make
whichever hard drive you choose be a bootable volume. The "System Tools"
and "Utilities 1" diskettes are both bootable -- Utils 1 has Disk First
Aid for basic diagnostics and directory repairs, and HDSC Setup for
initializing or formatting a hard disk. You can also make a bootable
hard drive by drag-copying the system folder from one of the floppies
to your hard drive, but it's better to use the installer so you get
all the goodies and doodads beyond the minimum system.
Actually, the last "free" version of the MacOS was 7.0.1 which, along with
some older versions, is downloadable from Apple's ftp site.
The files are distributed as diskette images from a program known as DiskCopy
(also downloadable at Apple).
Which version is a matter of personal taste. An SE with 4mb of memory will
run anything up to MacOS 7.5.5. Generally, most people stay to 7.1 or earlier
as the most of the 7.5 enhancements will not work on an SE anyway. System 6
is a much lighter weight OS (mainly due to the fact that it is single-
tasking), but is not compatible with some newer software.
One other note... out of the box, Apple HDSC setup will not recognize a
non-Apple SCSI drive. Patches do exist to allow it to do so. Otherwise,
I believe that there is one freeware/shareware disk formatter available.
<<<John>>>
P.S. If you decide to go with 7.0 or 7.0.1, make sure and also download the
"System 7 Tune-Up". Basically, it is an update which fixes some problems in
the original System 7 release that could cause the loss of folders.