4.6. Make your own boot CD.

Section contents:

• 4.6.1. Using SYSLINUX to make a bootable floopy.
• 4.6.2. Using ISOLINUX to make bootable CDs.
• 4.6.3. GRUB bootable CDs

4.6.1 Using SYSLINUX to make a bootable floopy.

The (in)famoun boot loader SYSLINUX, can't mount or read 'ext3' file systems like GRUB,nor it can get physical 3D coordinates (CHS) like LILO, it can read FAT file systems!! why FAT ?! it's designed to read FAT file system (the old 8.3 way, 8 characters for name and 3 for extention), a derived version of it called ISOLINUX could read ISO9960 file systems used with CDs, in both cases it could not be used to read and boot a kernel found on a native file system (like 'ext3'), it has limited usage at:

• create bootable floppies (eg. for installation).
• create bootable CDs
• boots a custom Linux installation where you put the kernel on Windows partition.

The syntax of 'syslinux.cfg' is quite simple, a 'label' followed by a short name, then 'kernel' line followed by filename (relative to floppy), and at last we have 'append' followed by arguments to pass like:

label linux
	kernel vmlinuz
	append initrd=ramdisk.rdz ramdisk_size=8000 root=/dev/ram3 vga=788

default linux
prompt 1 # 0 don't prompt unless shift or what ever pressed
timeout 80 # wait for 15 sec
display boot.msg
F1 help.msg
F2 boot.msg
label linux
  kernel alt0/vmlinuz
  append initrd=ramdisk.rdz ramdisk_size=8000 root=/dev/ram3 vga=788
label text
  kernel alt0/vmlinuz
  append initrd=ramdisk.rdz ramdisk_size=8000 root=/dev/ram3 2

4.6.2 Using ISOLINUX to make bootable CDs.

A branch of SYSLINUX is called ISOLINUX which is used in usual distributions bootable CDs. Let's assume you have a directory called '~/mycd' that will become an ISO image called 'mycd.iso' to be burned as a bootable CD, create a subdirectory called 'isolinux' inside that directory and put 'isolinux.bin' which is copied from ISOLINUX directory which vary from distribution to another, also create 'isolinux.cfg' file and put it in the 'isolinux' subdirectory, and put a kernel and a GZIP'ed ramdisk image (give it a '.rdz' name), we discuss how on '4.3. Linux under microscope.' section, and then create the image by typing :

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

4.6.3 GRUB bootable CDs

A document in Linux From Scratch Tips(www.linuxfromscratch.org) discuss how GRUB could be used as bootloader for CDs.