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Date:      Tue, 10 Feb 1998 01:31:56 -0800
From:      Mike Smith <mike@smith.net.au>
To:        Terry Lambert <tlambert@primenet.com>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: boot floppy banner 
Message-ID:  <199802100931.BAA00698@dingo.cdrom.com>
In-Reply-To: Your message of "Tue, 10 Feb 1998 09:18:52 GMT." <199802100918.CAA23887@usr05.primenet.com> 

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> > > I'll think about it; it's pretty trivial, I'm betting, except where
> > > the "extras" are concerned (they made some things vastly more complex,
> > > unfortunately).
> > 
> > Which things do they complexify, and how?  I'm not really attached to 
> > the way that the current "extras" stuff works; if there is a more 
> > ELF-friendly way to do it, then I'm all ears.
> 
> Mostly "knowing where it's safe to load a second stage ELF-based a.out
> booter below 1M".

How does this complexify the extras loading?  The "extras" rock up as 
more ELF segments, which the a.out booter can ignore.  If we have ELF 
as a reality for 3.0, I'll abandon any formal attempt to get the 
"extras" stuff into the a.out kernel.  The patches can remain for 
people that want/need them, but I don't see them having any real 
utility.

Of course, once you have written this a.out loader, you will have been 
sucked into writing the third-stage bootstrap I've been whining about 
for ages.  Then the "extras" loading moves there anyway, size stops 
being an issue, and you can handle both kernel types.

> One very real problem is that we need to start thinking in terms of
> running the initial kernel code (a second stage boot at a minimum)
> in real mode, and making it the kernel's responsibility to go to
> protected mode.

I'm still not entirely convinced of this.  Certainly we need more code 
in real mode, but whether that should be the third-stage boot or kernel 
startup I'm not sure.

> Have you looked at the GRUB code?  It claims to have FreeBSD patches
> available, though I'm sure they are quite dated.  It makes the same request
> for the kernel to do its own transition to protected mode.

I looked at it a while back; building it was an atrocious pain and I 
was somewhat put off by the blocklisting that it used and the 
unfriendly syntax of the CLI.  I've investigated a few other 
bootloaders, but ultimately the one I keep coming back to is the 
NetBSD-i386 standalone loader.

If you want to make a serious stab at a new bootloader for FreeBSD, 
*this* is the one you want.  It's a really nice piece of work, but 
removing it from the NetBSD kernel to allow it to be built on its own 
is something akin to ripping the living heart out of a rhinoceros 
using a dental probe.

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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