What is An Operating System or "OS" - A plain English explanation

What is an operating system? In this article I'm going to help you finally make sense of what for most people is one of the most confusing and least understood computer terms around: "operating system", or "OS".

This is actually a pretty easy idea to get when it's explained right.

Now what is an operating system, or OS? First off, it's is a type of software. I explained what software was in my last newsletter article (where I answered the question "what is driver") but here is a recap:

"Software" is all of the parts of the computer that you can't really see or touch. Software would include things like Microsoft Word, your email program, Windows or the Mac OS, plus all of your personal files like letters, photos, music, and more.

One way to think about it is like this: hardware is like your brain, the physical part of your body, while software is like your mind or your thoughts -- the non-physical part of yourself.

Software runs on hardware, just like your thoughts "run on" your brain.

Make sense? So let's get to the OS specifically.

First off, let me give a couple of examples: the two best known operating systems right now are Windows, and Mac OS X (pronounced "Oh Ess Ten" -- as in the Roman numeral ten).

Windows XP and Windows Vista are a couple different versions of the Windows operating system. While Mac OS 10.4 (also called "Tiger") and the newest Mac OS 10.5 (or "Leopard") are two different versions of Mac OS X.

So what *is* an OS?

Think of it this way: when a baby is born, they have the instinct to eat, breathe, and so on, and also the instinct to watch, listen, and absorb what's going on around them.

In time, a young child learns to talk and walk by learning from others, and as they get older, they also learn more fundamental skills like reading and writing, hand-eye coordination, and so on.

So in other words, they go from being able to do not a lot except eat, sleep, and fill diapers, to physical and mental maturity where they have all the general skills they need to learn more specific skills like driving a car, playing a sport like football, writing a paper for school, working a job, etc.

In many ways, when you turn a computer on, it's just like a newborn baby. It has the ability to turn on, and show an image on the screen, but that's about it.

The only other thing it can do is look at the hard drive, and if there is an operating system installed on it, the computer knows to start running the OS.

That process is called "booting", which is what happens between when you turn the computer on, and when you can actually start using it.

And the best way to think about it is that it's just like a child being born and growing up: the operating system contains the "life experiences" and lessons that give a child all the basic skills like walking, talking, reading, writing, and so on, that make everything else possible.

So in a sense, it's like your computer is born and "grows up" in the space of 30 seconds to a minute or so (or longer for some computers) that it takes to "boot" the operating system.

So in other words, the operating system is like those basic skills we all have and learned as children. More specifically, it's the software on the computer that creates the desktop, the icons on it, moves the little mouse pointer around on the screen when you move your mouse around, lets you view files and open, lets you type, and so on.

Without it, you couldn't do anything with the computer but turn it on and see an error message like "non system disk or disk error" on a Windows PC, or a flashing question mark on a Mac.

So even though a lot of people don't really understand what an OS is, or what it does, you couldn't use your computer without it.

Hope that makes sense.

Until next time, enjoy,

Worth Godwin