Information that the computer always needs, that cannot be changed or deleted (unless it is EEPROM), is normally kept in read-only memory (ROM), which does not lose its contents when the computer is turned off. Such items include the BIOS (Basic Input/Output System), which stores the most basic commands for the computer, telling it how it should start up. The BIOS also tells the computer how to input and output information. The BIOS can be compared to the part of your brain that tells your heart how to beat. This is an important part.