generic chain loader, map installer, and a simple boot partition setter.
LILO allows booting from multiple disks, and can have menus for choosing
different boot images. LILO is also able to pass command-line options
to the Linux kernel.
LILO does not depend on a specific file system, can boot Linux kernel
images from floppy disks and from hard disks, and can even act as a
"boot manager" for other operating systems.
(I have been using this in pkgsrc since November, 2002.)