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Date:      Mon, 15 Mar 1999 12:13:42 -0500 (EST)
From:      "Mark J. Taylor" <mtaylor@cybernet.com>
To:        Leigh Hart <hart@at.dotat.com>
Cc:        freebsd-hackers@FreeBSD.ORG, "Curtis Wilbar [STAFF]" <curtis@ici.net>
Subject:   Re: bootable cd q
Message-ID:  <XFMail.990315121342.mtaylor@cybernet.com>
In-Reply-To: <199903151245.XAA14560@at.dotat.com>

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Actually, it is not all that difficult (if I am reading your
question correctly): you just have to provide mkisofs with the
1.44 MB boot floppy image (or 2.88 MB).

If I remember correctly:
The EL-TORITO standard expects a certain header on the CD-ROM
("EL-TORITO", go figure), which points to a catalog file, which
has the location (in blocks, I belive) of the file to use for the
floppy image (during boot, the CD-ROM emulates the "A:" drive).
The image can be 1.44 MB or 2.88 MB (not sure if 720 KB is
acceptable).

On FreeBSD's 2.2.x's bootable CD-ROM, the floppy image used is the
standard GENERIC kernel with a MFS root file system (boot.flp).
I haven't figured out how 3.1 does it yet (there is a new 3-stage
boot loader now), but I'd bet that they are using a 2.88 MB disk
image, to get around the 2 boot floppy install.

If you want to use the CD-ROM's filesystem, then you should
investigate using  "-C" boot prompt.
Alternatively, in your /etc/rc script that is in the boot floppy
image, you can search for and mount the CD-ROM somewhere, and
chroot all of your commands.

Take a look at the src/release/ directory for boot floppy creation.
It's a little complicated to roll your own, but there are lots of
"templates" there.  :)



---
Mark J. Taylor                                   Networking Research
Cybernet Systems                                mtaylor@cybernet.com
727 Airport Blvd.                               PHONE (734) 668-2567
Ann Arbor, MI  48108                            FAX   (734) 668-8780
http://www.cybernet.com/                      http://www.netmax.com/



On 15-Mar-99 Leigh Hart wrote:
> Hi Curtis,
> 
> "Curtis Wilbar [STAFF]" <curtis@ici.net> wrote:
>> 
>> Can anyone point me to a website, ftpsite, etc that would detail
>> how to make a freebsd bootable cd-rom ?  I've found info on mkisofs
>> and in general how it works, but I'm looking for freebsd specific
>> info (i.e. how to make a bootable cd from the downloaded images/etc).
>> 
>> I'd appreciate any info you could provide.
> 
> cd /usr/share/examples/worm/
> 
> read it and weep (it is *not* easy).
> 
> then go to /usr/src/release and investigate write_mfs_in_kernel.c,
> you will need it.  The process has changed a bit since I did it on
> FreeBSD-2.2.5, so I won't go into detaills here about what I did,
> it was an ugly hack, but then again, el toro (yip yip yeehaa sp!??!)
> CD booting is ugly at the best of times.
> 
> Cheers
> 
> Leigh
> -- 
>| "By the time they had diminished | Leigh Hart, <hart@dotat.com> |
>|  from 50 to 8, the other dwarves | Dotat Communications Pty Ltd |
>|  began to suspect 'Hungry' ..."  | GPO Box 487 Adelaide SA 5001 |
>|   -- Gary Larson, "The Far Side" |  http://www.dotat.com/hart/  |
> 
> 
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