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Subject: Re: a question about boot-manager
To: freebsd@hopf.math.purdue.edu (Clarence W. Wilkerson)
Date: Tue, 30 Jan 96 10:13:17 MET
From: Greg Lehey <lehey.pad@sni.de>
Cc: hackers@freebsd.org, doc@freebsd.org
In-Reply-To: <199601272010.PAA08983@hopf2.math.purdue.edu>; from "Clarence W. Wilkerson" at Jan 27, 96 3:10 pm
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>
> I currently am running a system that has DOS, FreeBSD, and Linux loaded.
> I use the FreeBSD bootmanager, BootEasy. Because it uses the bios, my
> understanding is that the partitions it boots have to be visible to the
> bios. In my case, DOS is on first disk, FreeBSD on second, and Linux
> on the third. I boot linux by first booting DOS and then using
> Lodlin15 package to boot Linux. The dos directory contains a copy of
> the linux kernel which is read in and started. Then it knows about extra
> disks, and partitions beyond the usual limits.
>
> To do this on one large disk with only BootEasy, I think your DOS will need
> to be entirely low ( below 1023 cylinders ). Linux could be started from
> a very small partition containing essentially only a kernel, and I suspect the
> same for FreeBSD.

I'd like to confirm this.  It's my understanding that the only reason
to require partitions to be below the magic 1024 cylinder limit is if
they are bootable, so that the BIOS can address them.  In this
particular situation, you could do this by putting the primary DOS
partition, one of the UNIX slices ("partitions" in DOS terminology)
completely within the first 1024 cylinders, and the other UNIX slice
sufficiently in the first 1024 cylinders that the root partition is
below the limit.  The rest of the disk would include the rest of the
second UNIX slice and the DOS extended partition.

If you disagree with this, *please* complain.  I'm writing this in the
FreeBSD installation guide, and it would be nice if it were correct.

Greg