Like anybody waking up, your computer is hungry. But the computer hungers for more information. It checks to see if a bootable disk is in drive A:. If not, it looks to see if the hard disk is bootable.

A bootable disk is one that contains "system files." The basic three are MSDOS.SYS, IO.SYS and COMMAND.COM. You might have seen COMMAND.COM in the root directory of your hard disk or on an old floppy disk. The others are sometimes hidden from view. They are there, but you don't see them when you type "dir."

The computer then reads these system files. They tell it all about becoming a real computer. Once it reads these files, it knows how to run programs.

Just like when you read a book, the computer puts this information in short-term memory. On a computer, this is the RAM. These are several IC chips that can hold hundreds of thousands or millions of individual bytes.

Next, the computer will look for files called AUTOEXEC.BAT and CONFIG.SYS on the bootable disk. These are special files in which the user can write instructions to tell the computer to automatically load chosen programs.

The computer has a timing crystal which keep its thinking organized. Another timing crystal keeps track of the time and date. Most computers also have a small rechargeable battery and an IC chip that keeps track of the time even when the main power switch is turned off. This small part of the computer is always awake. This part of the BIOS system is called the CMOS, and can also contain some hardware configuration information, such as what type of hard disk you have, and whether you want the system to check to see if A: is bootable, or try the hard disk first. You can modify CMOS settings by pressing a key combination (often [DEL] or [Ctrl] + [Alt] + [S] or [F4]) when the computer first starts. Changing CMOS settings is not a good experiment unless you are really familiar with what they do. It is very possible to lose track of the settings necessary to operate the hard disk or the video system!

The timing crystal emits an electronic tick, tick, tick at a high rate of speed. The timing chip adds these ticks to the time and date. The battery keeps this going. Whenever the computer is turned on, the battery is recharged.

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