[comp.unix.sysv386] multiple bootable partitions

rreid@csuchico.edu (Ralph Reid) (10/14/90)

I am currently running MS-DOS 3.3 on a 80386 33 MHz machine.  I would
like to add something like UNIX or XENIX to a separate partition on
the 360MB hard disk.  I would like to then be able to boot up on
either MS-DOS or UNIX.  How do I do it?  Is there any software
available which might allow this type of operation?

Thanks.


--
Ralph.  SAAC member.
ARS: N6BNO
Compuserve: 72250.3521@compuserve.com
email: rreid@ecst.csuchico.edu

shj@login.dkuug.dk (Stig Jacobsen) (10/16/90)

rreid@csuchico.edu (Ralph Reid) writes:

>I am currently running MS-DOS 3.3 on a 80386 33 MHz machine.  I would
>like to add something like UNIX or XENIX to a separate partition on
>the 360MB hard disk.  I would like to then be able to boot up on
>either MS-DOS or UNIX.  How do I do it?  Is there any software
>available which might allow this type of operation?

The software you need is included with MS-Dos :-)  After you have
installed Unix, you can use FDisk (under either Dos or Unix) to
select between the partition to boot from (at the next boot).

The best would be if one were asked at boot-time which partition
that should be used for this boot, but ..

Just one thing to be aware of: Since you are using Dos 3.30 (not
4.0), it is very important that your bootable Dos-partition is
entirely contained within the first 65535 sectors (32meg) of the
disk - otherwise you won't be able to boot Dos from the
harddrive.

I just learned the hard way... On a 120mb disk, I installed Unix
on the first 90 mb and Dos 3.30 on the last 32 mb. All sorts of
problems and I had to repartition the whole drive.. (This is why
I have time for reading news - the other machine is busy
restoring a backup ATM ;-).

Note: All this doesn't apply to Dos 4.0x; it works fine even when
not booted from the first 32mb - but my vpix didn't recognize the
Dos 4.0 partition - lotsa fun...
--
Stig Jacobsen
shj@login.dkuug.dk

nvk@ddsw1.MCS.COM (Norman Kohn) (10/16/90)

In article <1990Oct14.095603.5272@ecst.csuchico.edu> rreid@csuchico.edu (Ralph Reid) writes:
>I am currently running MS-DOS 3.3 on a 80386 33 MHz machine.  I would
>like to add something like UNIX or XENIX to a separate partition on
>the 360MB hard disk.  I would like to then be able to boot up on
>either MS-DOS or UNIX.  How do I do it?  Is there any software
>available which might allow this type of operation?

Microport had this feature: you could type "dos" when the
/unix prompt came up at boot time, and it would boot from a 
dos partition.  This was presumably a feature of the
partition-specific boot code in the unix partition, and
I suppose that you could disassemble the uport boot code
for a hint of how they did it... but, if you're into 386
assembler etc., it shouldn't be too hard to do it.
You'd probably have to recognize the "dos" input, look back
into the drive's partition table, and load and jump to the
appropriate boot sector.  A good day's work, I'd say.

A good project for the public domain would be a "dummy"
fdisk partition, consisting only of boot program, which when
"booted" would ask which partition to boot, and then jump to it;
after a timeout it could jump to a default partition.
This would solve a lot of the "active partition" problems
and should be a feasible and portable project.

-- 
Norman Kohn   		| ...ddsw1!nvk
Chicago, Il.		| days/ans svc: (312) 650-6840
			| eves: (312) 373-0564

tvf@cci632.UUCP (Tom Frauenhofer) (10/17/90)

I'm cross-posting this discussion to comp.os.minix, as they might have just
the thing there:

In article <1990Oct16.145551.15653@ddsw1.MCS.COM> nvk@ddsw1.MCS.COM (Norman Kohn) writes:
>In article <1990Oct14.095603.5272@ecst.csuchico.edu> rreid@csuchico.edu (Ralph Reid) writes:
>>the 360MB hard disk.  I would like to then be able to boot up on
>>either MS-DOS or UNIX.  How do I do it?  Is there any software
>
>Microport had this feature: you could type "dos" when the
>/unix prompt came up at boot time, and it would boot from a 
>dos partition.
>
>A good project for the public domain would be a "dummy"
>fdisk partition, consisting only of boot program, which when
>"booted" would ask which partition to boot, and then jump to it;
>after a timeout it could jump to a default partition.
>This would solve a lot of the "active partition" problems
>and should be a feasible and portable project.

Earl Chew has written a bootstrap package called "Shoelace" that does just this.
I build it under Minix and set it up so that it loads from my hard disk.  You
tell it the default partition you want, it shows you a list of the disk partitions,
and you can select one.  After 15 seconds it times out and goes to the default.
It's pretty neat.  It's available from the Minix archives on various machines,
I forget which one I got it from.  It's a pretty well thought out piece of
software.

I don't know if it can be built under anything other than Minix, but I wouldn't be
surprised.
-- 
Thomas V. Frauenhofer, WA2YYW	ccicpg!cci632!tvf@uunet.uu.net	tvf1477@ma.cs.rit.edu
"Little cockroach on the wall/Don't you have no friends at all?
 Doesn't anybody love you?/God will love you! (SQUISH!)"

hv@uwasa.fi (Harri Valkama LAKE) (10/17/90)

In article <1990Oct16.145551.15653@ddsw1.MCS.COM> nvk@ddsw1.MCS.COM (Norman Kohn) writes:
>In article <1990Oct14.095603.5272@ecst.csuchico.edu> rreid@csuchico.edu (Ralph Reid) writes:
>>I am currently running MS-DOS 3.3 on a 80386 33 MHz machine.  I would
>>like to add something like UNIX or XENIX to a separate partition on
>>the 360MB hard disk.  I would like to then be able to boot up on
>>either MS-DOS or UNIX.  How do I do it?  Is there any software
>>available which might allow this type of operation?
>
>A good project for the public domain would be a "dummy"
>fdisk partition, consisting only of boot program, which when
>"booted" would ask which partition to boot, and then jump to it;
>after a timeout it could jump to a default partition.
>This would solve a lot of the "active partition" problems
>and should be a feasible and portable project.

It has been done already. Check mfdisk.zoo out. Available
from (chyde.)uwasa.fi (128.214.12.3) at pc/source dir.

-- 
== Harri Valkama, University of Vaasa, Finland ================================
  P.O. Box 700, 65101 VAASA, Finland  (tel:+358 61 248426 fax:+358 61 248465)
 hv@uwasa.fi hv@nic.funet.fi hkv@flame.uwasa.fi harri.valkama@wmac00.uwasa.fi
  Moderating at chyde.uwasa.fi (128.214.12.3) & nic.funet.fi (128.214.6.100)

ms234210@longs.LANCE.ColoState.Edu (Mark T. Spence) (10/18/90)

If you're looking for a UNIX that allows you to boot to DOS, look
to SCO. Both SCO XENIX and UNIX allow for multiple op systems at
boot-up

-------------------------------------------------------------------

From the desk of Mark Spence at ms234210@longs.lance.colostate.edu

"Keep the hands off the body!"--Gadget to Dale

(From 'A Fly in the Ointment')

tmh@prosun.first.gmd.de (Thomas Hoberg) (10/18/90)

You don't need a separate Partition just for the boot code. The space within
the MBB is quite sufficient to stuff a boot menu program into. I got one on my
machine: It will present me with a menu of all partitions on both drives 
connected to the primary controller, at boot up, and I can load any operating
system from any partition by entering 1..8. I admit it's a tight fit and error
messages are textually short (BEEP) but it works nicely. It comes with the
AX operating system developed at the Berlin Technical University, but the
source I should have somewhere (but not here), assembles with MASM or TASM.
There is no installation utility, so you would have to patch in the correct
partition table yourself, and then transfer it to the boot block. If there
is sufficient interest (EMAIL please), I'll post the sources and maybe even
add an installation utility.

jeff@uf.msc.umn.edu (Jeff Turner) (10/20/90)

In article <481@prosun.first.gmd.de> tmh@prosun.first.gmd.de (Thomas Hoberg) writes:
>AX operating system developed at the Berlin Technical University, but the
>source I should have somewhere (but not here), assembles with MASM or TASM.
>There is no installation utility, so you would have to patch in the correct
>partition table yourself, and then transfer it to the boot block. If there
>is sufficient interest (EMAIL please), I'll post the sources and maybe even
>add an installation utility.

My mail to you bounced.

I think there will be sufficient interest to post (a lot larger things
with less interest are posted daily).

If you don't want to post, I would appreciate a email copy as I am
tired of booting off of floppy when I want to run DOS on my 386 
UNIX box.

Thanks much, Jeff.

---
Jeff Turner                  Minnesota Supercomputer Center, Inc.
(612) 626-0544               1200 Washington Avenue South
jeff@uh.msc.umn.edu          Minneapolis, Minnesota  55415

raymond@gem.stack.urc.tue.nl (Raymond Nijssen) (10/24/90)

ms234210@longs.LANCE.ColoState.Edu (Mark T. Spence) writes:
>If you're looking for a UNIX that allows you to boot to DOS, look
>to SCO. Both SCO XENIX and UNIX allow for multiple op systems at
>boot-up

It's not that difficult to write a simple program residing in the partition
table which allows you to select from which partition you want to boot.
(in fact, many viruses make use of this method)

A friend wrote such a program and donated it to the PD. After the primary
bootstrap, you get a menu from which you can select a partition by pressing
one single character. Otherwise, after a configurable time-out, it assumes
the specified default.

This program is downloadable from our BBS (+31) 40-456744, and it will
soon be available by anonymous FTP at ftp.win.tue.nl

Have fun,
-Raymond