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El Torito CDROM cdrw

The floppy image was needed only for old BIOSes that didn't expect to boot from a CD.

Today, bootable CD's are unlikely to have this; see El Torito (CD-ROM standard) at Wikipedia for more details.

Message-ID: <38C42E39.F5756B7C@mail.com> 
Date: Mon, 06 Mar 2000 15:16:25 -0700
From: Warren Young <tangent@mail.com>
Newsgroups: comp.unix.sco.misc
Subject: Re: Making a Bootable CDROM
X-Original-NNTP-Posting-Host: 56k7-118.cyberport.com

Wilson Gardiner wrote:
> 
> I do not know about you but I am sick of getting problems with dirty floppy
> drives when we need to boot from root and boot floppies.
> 
> What I want to do is to take an image of a 2.88Mb root and boot floppy and
> put it onto a CDROM so that I can boot from it.

Only a few tools can create El Torito CD-ROMs -- read your docs to find
out if yours do handle this.

The key about an El Torito CD-ROM is that the first session on it is a
1.44 MB 3.5" floppy image.  (I don't know if you can use a 2.88 MB image
here or not.)  The BIOS does a little magic to make this image appear to
the system as a floppy drive, then boots into it normally.  (I think you
can still get at the "real" floppy drive, but I don't know if there are
hoops you have to jump through to do this.)

Your boot image should contain a basic OS, and some kind of startup
script that will mount the CD-ROM, and perhaps load more stuff from the
CD-ROM.  An El Torito disk is a multi-session disk, so the mount command
will see the second session: the ISO-9660 part, which contains the major
part of the CD's data.

A simpler option is to create a plain-Jane ISO-9660 CD with tools like
rawrite and image files of a boot floppy that mounts the CD.  If your
boot floppy gets corrupted (or if you lose it) you can easily make
another from any DOS box.
-- 
= Warren -- See the *ix pages at http://www.cyberport.com/~tangent/ix/
= 
= ICBM Address: 36.8274040 N, 108.0204086 W, alt. 1714m

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