Program run at
boot time, which allows you to pick which one of several
operating systems, on which of several
partitions and
disks, to boot. Most
Linux users use the (
free)
LILO program, which also functions as a boot manager.
Commercial variants exist, too; most have added support for booting Linux to their traditional support for systems like Windows 95, Windows NT, OS/2, and the branded PC-Unix systems.