A boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the OperatingSystem Kernel.

A multiboot loader offers a menu and the ability to select from a list of operating systems.

Multiboot loaders include:

• GRUB
• LILO
• SysLinux
• Windows' NT Bootloader, NTLDR

You can chain bootloaders, so for example, grub can then call Windows' bootloader (this is the preferred method for DualBooting Linux and Windows.)

There's also a strange beast called LoadLin.

Sweet sweet bootloader at http://btmgr.sourceforge.net, which will let you boot from a CD when your BIOS only supports booting from a floppy/whatever.