BIOS

BIOS is an acronym for Basic Input/Output System.

BIOS is a computer program stored in a Read Only Memory (ROM), which is always available and cannot be lost due to a disk crash or power failure.

Among other things, the BIOS allows the computer to boot up and tells the computer what devices are available/hook-up to it; it also contains clock information. There are different versions of BIOS programs, and it is not unusual to find two different versions of BIOS sold on two computers on the same day from the same manufacturer.