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Making a bootable CD from a bootable floppy image

Copyright (C) 2003 by Steve Litt, All rights reserved. Material provided as-is, use at your own risk.

Steve Litt is the author of Troubleshooting Techniques of the Successful TechnologistRapid Learning: Secret Weapon of the Successful Technologist, and Samba Unleashed.


Executive Summary:

A big thank you goes out to LEAP member Mark Alexander for supplying much of the technical information in this document...

If you're old enough to remember IT in the 1980's, you remember a time when floppies were reliable. They had to be. For most PC type computers, floppies were the preferred software distribution media. and the preferred backup media. Skip ahead 20 years, and floppies are almost never used for these purposes. My observation using floppies is that manufacturers of floppy media and drives no longer insist on high quality. Why bother -- the last use of floppies is boot media for computers.

My experience indicates you might need to try 5 or 6 floppies before you get a good boot floppy. This is a hardship, to say the least.

Meanwhile, CD media and drives have gotten better and better over the years. Wouldn't it be nice if you could burn that floppy image as a bootable CD, and then use the CD as installation media? Keep in mind that most computers made in the last 5 years can boot to CD.

This document describes how to burn a floppy image file onto a CD. For this exercise we'll use /scratch/linuxinst/m91inst/images/network.img as the image to burn.

Mastering And Burning It the Easy way

Assuming the floppy image file to be turned into a bootable CD is /scratch/linuxinst/m91inst/images/network.img, master CD image /tmp/cd.iso with the following command:
mkisofs -pad -b network.img -R -o /tmp/cd.iso /scratch/linuxinst/m91inst/images/network.img
Note the following:

Command parameter or part
Add padding to the end to make it readable on all CD players
-b network.img
-b tells mkisofs which *floppy image* to use for booting. If the floppy image boots as a floppy, it will boot as a CD. Note that there is no path prepended to network.img. The network.img bootable image is assumed to be relative to the file being imagized, in this case
Include Rock-Ridge extensions for readability everywhere
-o /tmp/cd.iso
This defines the output file, an ISO9660 image ready for burning
This is the file to put on the CD.

Your next step is to actually burn it. Use the following command:
cdrecord dev=0,3,0 speed=12 blank=fast -pad -v -eject /tmp/cd.iso

Command parameter or part
The CD burner device. If you don't know it, use the cdrecord -scanbus command to find out.
Set this to the fastest speed supported by your burner/media combination.

Use this ONLY if burning a rewriteable. This erases the current CD contents, but does it fast rather than thoroughly.
Add padding to the end to make it readable on all CD players. Without this, the CD will error out when read on many Linux boxes
Eject when finished
The ISO image you're burning. In this case it's the ISO you just made with mkisofs.

Remove the CD, and boot it on a machine known able to boot CD's. You should get a bootable version of whatever boot floppy image you used. The advantage to a boot CD is CD media are much more reliable, so you needn't go through several floppies finding just the right one to burn properly.

Mastering and Burning it the Complete Way

The easy CD boots and installs just like the floppy, but it does not contain the floppy's files in the root of the CD. To get all the files visible in the root, you need to create a temporary directory, copy all the floppy image files to it, copy the floppy image to it, and run mkisofs. The cdrecord step is the same as described in the Mastering and Burning it the Easy Way article:

As mentioned before, you must determine your device number based on cdrecord -scanbus, and your speed based on media and drive.

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