Creating a Bootable CD-ROM

I have no idea if creating a bootable Linux CD is trivial or not because I don't have the experience. But here is the how-to.

CD-ROM file tree

Createing a bootable CD under Linux requires to create an ISO image first and mkisofs is the right program for this. mkisofs expects the file/directory tree for the CD-ROM as input. A working sample layout is

isotree/
  isolinux/
    initrd.img
    isolinux.bin
    isolinux.cfg
    linux.tgz
    vmlinuz

where isotree becomes the root directory of the CD-ROM (isotree will not be copied to the CD-ROM, only its contents).

The files are

initrd.bin

the initrd image.

isolinux.bin

part of the syslinux package.

isolinux.cfg

the boot loader configuration file, see below.

linux.tgz

the target Linux image.

vmlinuz

the Linux kernel compatible to the initrd image.

A suitable isolinux.cfg is e.g.

default vmlinuz initrd=initrd.img im=/isolinux/linux.tgz

timeout 100
prompt 1

label linux
  kernel vmlinuz
  append initrd=initrd.img im=/isolinux/linux.tgz

Creating the ISO filesystem

To create the isofs from the filetree I use the command

# mkisofs -o ariane.iso \
    -b isolinux/isolinux.bin -c isolinux/boot.cat \
    -no-emul-boot -boot-load-size 4 \
    -boot-info-table isotree

from the directory which contains the isotree directory. The resulting image and be written with k3b.