What is Bios

BIOS is an acronym that stands either for the Basic Input/Output System or for Built In Operating System

A better explanation is the firmware of the computer. With the even of Linux, Apple and Windows running on the same hardware the firmware has been relabeled "Open Firmware", but the BIOS term persists.

It does provide a way of talking to the basic devices such as disk drives, keyboard and selecting the boot device and order. A BIOS password does provide a "little bit" of security.