Winn L. Rosch Hardware Bible, Sixth Edition

Background

Although mostly invisible and oft forgotten, your computer's BIOS is nevertheless one of its most important and enabling parts. The BIOS is, in fact, the one essential constituent that distinguishes one computer from another, even when they both share the same microprocessor, motherboard, and support hardware.

Firmware

Strictly speaking, however, the BIOS isn't hardware at all, even though it is an essential part of your computer's hardware. The BIOS is special program code—in a word, software—that's permanently (or nearly so) encapsulated in ROM chips or, as is most often the case with newer computers, Flash memory. Because of the two-sided aspects of the BIOS, existing in the netherworld between hardware and software, it and other ...