What is a BIOS?March 21, 2010
BIOS is an acronym meaning Basic Input / Output System. It is stored in a chip called ROM (read only memory). Most of the latest motherboards now use EEPROM’s (Electrically Erasable Programmable Read-Only Memory) (also called “Flash” BIOS) which can usually be upgraded by the user. (The earlier versions of the BIOS had to have the chip physically removed and replaced with a another chip programmed with a later BIOS version). When you switch on your computer the BIOS is the first program to run . It initializes and tests the hardware in your computer (called Power On Self Test or POST).
When everything is running, the BIOS program initiates and loads the operating system. The information in the BIOS can be changed by running Setup (sometimes called CMOS Setup). A set of routines called Run-Time Services, which is also a function of the BIOS, help operating systems and application programs to manage the hardware.