BIOS stands for Basic Input and Output Software. The BIOS is software that controls the most fundamental operations of a computer and a BIOS is necessary in order to start a computer. Without a BIOS, a computer would not know how to communicate with its hard disk and other devices. The BIOS is stored on a ROM (Read-Only Memory) computer chip inside the computer. Many computers in the past few years use "Flash EPROM" chips, which means the BIOS chip can be reprogrammed with an updated BIOS. A BIOS may need to be updated to fix bugs, such as the year 2000 bug, or an update may be necessary in order to support new hardware protocols.