Re: I've been asked a question . . .

Peter Meric (pmeric@nospam.socs.uts.edu.au)
Fri, 11 Nov 1994 09:55:26 +1100 (EST)

On Fri, 11 Nov 1994, Anand Kumria wrote:

> On Thu, 10 Nov 1994, Colin Panisset wrote:
>
> > Once upon a time, Matthew Young was heard to say:
> >
> > }
> > } I've been asked a question about "SCO Unix" - has anyone heard of
> > } this ??? The person concerned looks after a number of machines that have
> > } 2 hard disks each with OS2 on one hard disk and DOS on the other - he was
> > } "told" that DOS _needed_ to be on the first hard disk and wanted to know
> > } if "SCO Unix" also needed to be on the first hard disk.

Well, DOS needs to be on the first hard disk, as far as it's concerned. This
does mean that one can trick DOS into thinking this (like lilo does).

> > I'd advise the person in question to search out 'lilo' from somehere
> > like sunsite.unc.edu or tsx-11.mit.edu (the Linux archives). It allows
> > you to have multiple boot images under a single boot sector, and lets
> > you choose your boot image at a boot prompt.
>
> Not operating system _has_ to be on the first hard disk, a good
> boot loader will make it think (the OS) think it is loading from there
> however. With regard to LILO, if you check out it's docs (somewhere on
> sunsite.unc.edu:/pub/Linux/docs/lilo/<tech|user>.<dvi|ps> on mirrored on
> smug.student.adelaide.edu.au) it goes on at length about the PC boot
> process and how you can use LILO to master it. It also mentions some
> other boot loaders which are more capable than LILO when it comes to
> booting OSs off different hard disks.

lilo has a few drawbacks when booting DOS off a logical or extended partition.
DOS expects to be booting off a primary partition (ie. first partition on first
drive). In order to boot DOS off a non-primary partition, lilo modifies the
base address of the hard disks, which, in my opinion, is a *bad* thing.

Boot Manager, which comes with OS/2, doesn't allow DOS to be booted off a non-
primary partition (so is seemingly simpler and less powerful than lilo). OS/2
can, of course, boot off non-primary partitions, so there is no problem here.
Other Operating Systems can be added to the Boot Manager, such as linux,
without any problems.

To sum up, if SCO must be booted off a primary partition, then either let it
(and not use DOS [not that anyone would]), or take your chances with lilo.

If I am completely wrong about lilo, we're sure to find out, aren't we? :-)

Peter

PS. It is often a really good idea to proofread your correspondence before
posting, Anand.

------------------------------------------------------------------------
Peter Meric pmeric@nospam.socs.uts.edu.au
pmeric@nospam.ftoomsh.socs.uts.edu.au
pmeric@nospam.banksia.itd.uts.edu.au

"The integrity of some computer systems could be proportional to the
capabilities of some or all of its administrators, but probably isn't."