So what is the secret of the BIOS? How does it do all these wonderful things? Inside, the BIOS contains programs. You might say it's "software on a chip" or firmware.

This software is burned in the chip at the factory. So it can't be changed. The CPU can get help from the BIOS, but can not change how the BIOS does things. In more technical terms, the CPU can read from the BIOS, but not write to it. This type of chip is called a ROM chip.

The BIOS is usually contained in one or more ROM chips. These are physically located on the motherboard. These chips usually have a stick-on label with the word BIOS and other information.

Some newer PCs and laptops have a newer type of BIOS called flash BIOS. This means you can upgrade the BIOS chip by running a software program. This is easier than upgrading older BIOS chips, which require complete replacement.