What is LILO?
LILO stands for Linux Loader. It acts as a boot loader for Linux, which basically means that it loads Linux into the memory and then starts the Operating System. It also manages dual boot.
When a computer starts up, the BIOS first checks things and then hands over control to the Master Boot Record (MBR). This is where LILO is stored. When installed in the MBR, LILO allows for fast boot up of Linux. LILO is also customizable thus allowing the user to modify the default configuration as required.
However, LILO may be hampered by the fact that most computers do not allow for the modification of MBR thus rendering LILO as useless. There are alternative approaches to this, however, they usually take longer.
Some other boot loaders that can act as an alternative to LILO are LOADLIN (LOAD LINux) and GRUB (GRand Unified Bootloader).