BIOS

Just as animals rely on instincts to survive in the real world before they can learn from their experiences, a computer has a built-in program that tells it what to do before you load any software. This program is called the Basic Input/Output System because it tells the computer's microprocessor how to get input from the outside world and send output there. The BIOS defines how a computer acts and behaves before you load software. In modern computers, the BIOS has several additional functions, all essential to making the computers get started and work.

Unlike the microprocessor and chipset, the BIOS is mostly ephemeral: It is a program, a list of software codes. It takes physical form because it permanently resides in a special kind of memory chip, one that retains its memory without the need for electricity. This way, the BIOS program is always remembered, ready to be used as soon as the computer gets switched on. The chip holding the BIOS typically is a large flash memory chip. Its most distinguishing feature is its label, however. Because it holds software, the BIOS chip is usually emblazoned with a copyright notice just like other software products.