Bits'n'Bytes

As heard on CJCD

Episode 50

Okay, I don't get many questions about this one, but I do get a few. What is your computer's BIOS and what does it do?

BIOS stands for Basic Input/Output system. The BIOS is the first thing that's run on your computer when you turn it on. It's pretty much hard coded onto a chip on your motherboard and contains information for computer to access stuff like your keyboard, mouse, hard drives and CDROMs. Quite often it also performs the POST or Power On Self Test on your computer. For computers that don't have a logo of some kind hiding it, you can see the POST happening as the BIOS helps determine what kind of hard drive and CDROM are on the computer and as numbers from the memory test appear.

The BIOS also accesses information stored on another chip, called the CMOS. The CMOS contains information like the date and time, in what order to boot your floppy, your CD and hard drives and, if you have any, any power-on passwords. The CMOS usually needs a small battery to maintain its information. So if you see your clock on your computer starting to speed up or slow down, or if it keeps reverting to some day a few years ago, it's an indication that it's time to have the battery changed.

Usually, the BIOS is used by techie guys to do a little bit of system diagnosing. By changing the boot order of your computer, we can access a lot of stuff most of you can't. The BIOS can also give us information to let us know stuff like: if your hard drive or CDROM is working right, or not, or if your system is overheating. We can also use it to turn stuff on or off on your computer. Want to be sure no one can use the floppy drive or a thumb drive to take stuff off your system? These features can be turned on or off in the BIOS.

Stay tuned next week when I talk about building web sites.

I’m Computer Dave, thanks for your time.