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Path: utzoo!attcan!uunet!samsung!xylogics!transfer!lectroid!ddsw1!nvk
From: nvk@ddsw1.MCS.COM (Norman Kohn)
Newsgroups: comp.unix.sysv386,comp.unix.msdos,comp.unix.questions,unix-pc.general
Subject: Re: multiple bootable partitions
Summary: uport had it
Keywords: Is it possible?
Message-ID: <1990Oct16.145551.15653@ddsw1.MCS.COM>
Date: 16 Oct 90 14:55:51 GMT
References: <1990Oct14.095603.5272@ecst.csuchico.edu>
Reply-To: nvk@ddsw1.MCS.COM (Norman Kohn)
Organization: ddsw1.MCS.COM Contributor, Wheeling, IL
Lines: 29

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
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