LILO

LILO is one of the first boot loaders for Linux that was capable of booting from the hard disk, dating back to 1992⁴. It's still the market leader and over the years it was updated with new features such as a nice boot menu and the use of the new BIOS functions that eliminate the 1024 cylinder limit. The basic working principle of LILO has stayed the same. This means that most work is done by the installer and not by the boot time code. LILO is the only boot loader that supports booting from a RAID system.

All Linux distributions already have LILO installed, but not necessarily the latest version. In this example we will download the latest version of LILO. At the time of writing, the latest version of LILO was 22.3.1, Unpack the source tarball and make. This is easy as long as you have a sufficiently recent version of bin86 installed. The file README.common.problems tells you where to get it. We won't install LILO for now, but run it from the source directory where it was built.

If you have read the ``Getting Linux into Small Machines'' article, the following may be familiar to you, but we will do a few things differently:

• We will install on an overformatted diskette. This is not necessary for the current kernel and initial RAM disk, but for larger files, this may become necessary.
• We will use the minix file system instead of ext2. This has less overhead. The booted kernel need not support minix file systems, the host system must.
• We will use a boot menu.

First create the file lilo-initrd.conf with the following contents:

prompt
timeout=100
boot=/dev/fd0u1722
map=/mnt/boot/map
disk=/dev/fd0u1722
geometric
install=/mnt/boot/boot.b
image=/mnt/boot/zImage
  label=linux
  root=/dev/ram
  initrd=/mnt/boot/root.img.gz
image=/mnt/boot/zImage
  label=noram
  root=/dev/fd0u1722

Note the following:

• Specify /dev/fd0u1722 as the diskette device.
• Using this version of LILO and an overformatted diskette, I was unable to use the compact option. This option works for normally formatted diskettes. The speed penalty for not using this option is not as great as with LILO 21.4.
• Using the prompt and timeout options we cause the menu to appear immediately and the default option to be booted after 10 seconds.

Finally type the following commands to format the diskette, make a minix file system on it, copy the files and run LILO:

fdformat /dev/fd0u1722
mkfs.minix /dev/fd0u1722
mount /dev/fd0u1722 /mnt
mkdir /mnt/boot
cp zImage /mnt/boot
cp root.img.gz /mnt/boot
cp lilo-22.3.1/boot-menu.b /mnt/boot/boot.b
lilo-22.3.1/lilo -C lilo-initrd.conf
umount /mnt

Instead of boot-menu.b there is still the old-style boot-text.b, giving exactly the same interface as old LILO versions and boot-bmp.b to show a bitmapped screen. You can try all three of course.