Date: Tue, 17 Sep 1996 09:42:48 +0200 (SAT) From: Robert Nordier <rnordier@iafrica.com> To: dunhamal@cuug.ab.ca (Alan Dunham 284-9866) Cc: questions@FreeBSD.org Subject: Re: dos + FreeBSD 2.1 on IDE, dos needs format Message-ID: <199609170742.JAA01390@eac.iafrica.com> In-Reply-To: <199609161809.MAA13631@sun.cuug.ab.ca> from Alan Dunham 284-9866 at "Sep 16, 96 12:09:40 pm"
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Alan Dunham 284-9866 wrote:
>
> Hi: I have just installed FreeBSD 2.1 on a new IDE disk (Fireball 1.2).
> I set up a 400Mb partition for DOS before I installed FreeBSD on the
> rest of the drive. But I didn't format C: first (not thinking ahead,
> I guess). Now that FreeBSD is up, I am afraid to format C: because I
> don't trust DOS software.
>
> I have an archive of 386bsd & FreeBSD newsgroups since Aug 92. I can
> almost always find a solution to any problem I have by looking there.
> But it seems that no one else has made this mistake.
>
> -Is there a way of doing a DOS format from BSD on /dev/rwd0s1?
> -If I format C:, will it leave my BSD partition (slice) intact?
> -If I change the CMOS to tell it that C: has only 813 cylinders instead
> of the actual 2484, then will format C: leave BSD alone?
> -Will a dos format destroy the BSD boot manager & boot blocks &
> disklabel?
There isn't a FreeBSD utility to handle this, but the MS-DOS 'format'
command shouldn't give you any trouble. (I wouldn't recommend messing
with the CMOS, though.)
The MS-DOS format utility doesn't do a "low level" format. Apart
from writing the DOS filesystem structures (at the very start of
the partition), it just checks for bad sectors. So it wouldn't be
writing near your BSD partition, anyway.
The boot manager generally occupies the first cylinder of the disk,
and can be overwritten by the MS-DOS 'fdisk' utility, for instance.
(And it is also overwritten by default during a Windows 95
installation.) However, you can just copy it back onto the disk,
if that happens.
If you want to be able to boot DOS or Windows, you would also have
to 'sys' the filesystem ("format c: /s" amounts to the same thing).
If you'd really prefer to avoid using Microsoft software, I wrote
a replacement 'format' utility in C which runs on DOS, handles hard
drives, and is available on the Internet. (You could read or patch
the code so as to be sure of what it was doing.)
Anyway, reformatting a DOS partitions while BSD is already installed
is not particularly risky.
--
Robert Nordier
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