Need way to run multiple UNIXes on same 386 box

[Tony Olekshy]

In message <1187 at vsi.COM>, friedl at vsi.COM (Stephen J. Friedl) writes:
>
> I will soon have the "opportunity" to run two different versions of UNIX
> on my 386 (along with DOS) [how do I select the OS to boot?]...
>
>         [3] boot a DOS program that prompts for the partition.
>
> ...  Choices [2] or [3] might allow me to run everything on a big
> (~700MB) drive, and I guess this would be best if I could find
> it.  A friend of mine recalls vaguely seeing something about [3]
> but has no idea where he saw it.

I once ran 2.1.3 here and I didn't have the ability to boot DOS from the
"boot:" prompt.  I had a Xenix utility that feed fdisk the keystrokes to
activate the DOS partition, after which I haltsys'd; and a DOS utility to
feed FDISK.EXE the keystrokes to activate the Xenix partition, after which
I alt-ctl-del'd.

Soo... if you put DOS on the first 32Mb of a big disk (perhaps using a
WD1007-WA2 or one o' them cacheing controllers to make Xenix think it
has less than 1024 tracks) and split the rest between the two Unixes,
then a pair of utilities under each OS (named after the other two OSs),
might do the job.

Now the disclaimer: I am currently running a 25MHz AMI 386 with a ~320Mb
MiniScribe 9830e &c.  I tried an Adaptec 2322 (or such), which worked
fine under DOS, but Xenix croaked (I have about 2 dozen pages of notes
on attempted configurations, so it wasn't lack of effort).  I got a
WD1007-WA2 to try, and Xenix likes it.  Now, however, responding "dos"
to the "boot:" prompt sends the machine to never-never land.  Instead, I
leave a DOS boot floppy in the drive, which is labelled...

		     *** OPERATING SYSTEM LEVER ***

When someone wants to see the Adobe Illustrator, I just tell them to

		  *** Throw That Lever Over There ***

and `reboot`.  Finally, although the Illustrator ran fine with the Adaptec,
it gets in trouble with the WA2.  Periodically (don't know distribution),
it stalls for 15 seconds and I get a pop-up "Can't Access Hard Drive"
dialog box.  A response of "Retry" always succeeds with the screen update
I was waiting for, almost immediately.  However, this only works if I turn
off the disk cacheing software, so Windows is now *paging*to*disk*.  If
you though unbatching news was hard on your drive, you should see this ;-(.

I am planning to either get the Xenix ESDI upgrade and go back to the Adaptec,
get a cacheing controller that the manufacturer assures me will work with
Xenix 2.3.1 and Windows/386, or wait until SCO Unix V stabilizes.  Comments?

[Comments?!  That was supposed to be a disclaimer!]

Yours, etc., Tony Olekshy (...!alberta!oha!tony or tony at oha.UUCP).