A team of professional coders build it but the community at large isn't part of its conception. It's costly to produce and as you can probably guess, that cost is passed on to the end user: the consumer. Open source software on the other hand is free. Free to download, free to install, free to use, free to modify, and free to share. As a result, you can find tons of games, databases, GPA systems, weather reporting programs, and even small encyclopedias on these things - each accessible not at the click of a mouse - but at a few presses of a free thumb. Of course a mini keyboard is available for the text-messaging fan or for the poor fellow who can't seem to get away from the office. As you can imagine, the cumbersome process of switching from floppy to floppy prompted the birth of the operating system. An operating system is a software program that controls how the computer's hardware (and installed software) works. It manages the activity of every component and then displays that activity as a user-friendly interface (GUI). art - This extension indicates an image file that was compressed with AOL (America Online) technology. Both Internet Explorer and the AOL service software can display this kind of file, however if you don't have AOL installed on your system, Internet Explorer will display it. .avi - This extension indicates a video file playable by most multimedia viewers including Microsoft's Media Player. We always say, "'Tis better to screw up something on an old, used machine than to screw up everything on a brand new one!" A couple of errors on an old, used machine are easier to fix because someone is going to have the experience and knowledge to fix it. Errors on a new machine however can be a beast to fix because we're all knocking at Microsoft's door looking for answers. Think back to the last time that you paid a bill over the phone. Instead of speaking to a human being, chances are that you spoke to a computer that not only responded to what you said and followed the commands that you gave it, it also asked you for more information such as your full name or credit card number.