*BSD News Article 99176


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From: "Jordan K. Hubbard" <jkh@FreeBSD.org>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Creating a boot floppy
Date: Mon, 07 Jul 1997 21:55:12 -0700
Organization: Walnut Creek CDROM
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To: Test <jim@carroll.com>
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[posted and emailed]

Jim wrote:
> 
> I am trying to create a boot floppy for a FreeBSD 2.2.1 system, but am
> having alot of trouble.  My basic problem boils down into not knowing
> what to include on the floppy to boot a "minimal" system.

Well, you're missing /bin/sh for one thing - how is system supposed to
come up single user?  Also, single user is *all* you can do with no
startup scripts in /etc.

In any case, this really isn't the way to get to where you're going
since you'll quickly find that the kernel and a couple of utilities are
all you're able to fit, and this falls far short of a truly usable boot
floppy.

The installation boot floppy contains just a gzip'd kernel with an MFS
filesystem (also compressed) compiled into it.  The kernel decompresses
itself and the MFS image and then copies the MFS image into memory as
the root fs.  The contents of the MFS image are, in turn, "crunched" to
achieve even more space savings.

In other words, the tricks we had to pull to get a truly usable boot
floppy were insane and you should now give up if you're not willing to
do similar things.  ;-)  Read /usr/src/release/Makefile to see just what
I'm talking about here.
-- 
- Jordan Hubbard
  FreeBSD core team / Walnut Creek CDROM.