From DSL Wiki
LILO (LInux LOader)is a generic boot loader for Linux.
LILO does not depend on a specific file system, and can boot an operating system (e.g., Linux kernel images) from floppy disks and hard disks. One of up to sixteen different images can be selected at boot time. Various parameters, such as the root device, can be set independently for each kernel. LILO can be placed either in the master boot record (MBR) or the boot sector of a partition. In the latter case something else must be placed in the MBR to load LILO.
At system start, only the BIOS drivers are available for LILO to access hard disks. For this reason, with very old BIOS, the accessible area is limited to cylinders 0 to 1023 of the first two hard disks. For later BIOS, LILO can use 32-bit "logical block addressing" (LBA) to access practically the entire storage of all the hard disks that the BIOS allows access to.
LILO was the default boot loader for most Linux distributions in the years after the popularity of loadlin. Today, most distributions use GRUB as the default boot loader.