In the past I’ve written a series of articles on computer basics. Anybody who wants to improve their grasp of the basics on the subject should study them in the following sequence:

First
Second
Third
Fourth
Fifth

To those we will now add this one.

If you’ve ever wondered what happens between you turning on your computer and the computer being fully booted up to the point where you can open programs and files etc., today is your lucky day. The computer term we’re covering today addresses that. When you turn on the computer, four things are in play:

First, there is a Power-on Self Test (where the computer checks itself and its basic components). That’s abbreviated POST. For example, if the computer is set to alert you if a keyboard is not connected to it, and you unplug the keyboard and turn the computer on, you’ll see an error that reads something like “no keyboard present or keyboard error”. The POST is what gave you that message.

Second, the computer must find a device to boot from. Whether is your hard drive, a CD, or something else, the computer checks in a pre-determined sequence all the possible sources it can boot from. And then it turns over control to that device, which then loads the operating system. Classically, that’s when you see the Windows logo on your screen for the first time. If, however, the computer goes through all devices that can potentially provide an operating system to boot from and it doesn’t find it in any of them, you’re likely to see an error message like “No device to boot from” or maybe “Boot file missing” or something to that effect.

Third, the computer must have information on what different components are connected to it and how to control them.

And fourth, the computer must have a program where it can store basic information about what devices there are, the date and time, and some other settings related to the computer (such as what’s mentioned above about in what sequence should the computer look for a booting device).

All the above elements are handled by the Basic Input/Output System. You might have run across the computer term BIOS. That’s the abbreviation for it.

So, BIOS is a chip (a set of electric circuits) in your computer that performs all the above mentioned functions. It can remember basic information stored in it, even if you power the computer off and unplug it, because it draws power from a small battery that allows it to do so. And some of the most basic information it can store regardless of whether it is powered or not.

I have covered today’s basic computer concept while trying to avoid mentioning terms that are not defined in this article. However I do recommend going over the above mentioned first 5 articles that cover the computer basics from scratch to have a better understanding of today’s term.

Hope this helps.