Real Player and QuickTime are the first programs we think of when we think about multimedia. But Windows Media Player, also free and pre-installed, does a fine job at transmitting Internet-bound sound and video. With this application, you can easily listen to .wav files, .midi files, and even tune into a little Internet radio if you like. But in an environment where there are five, ten, twenty or more computers, buying a license for each computer can be down-right costly. So costly that the temptation to pirate a little software here and there can be pretty tempting. Co-workers are familiar with this temptation and they're often the ones who "share" purchased software among those who need it. Identifying Compressed Files Most files are compressed in .zip format (if you're using Windows) or .sit format (if you're using a Mac). The two most popular software programs used to compress and decompress files are Winzip and StuffIt respectively. There are other programs that do the same thing and there are even programs that can compress and decompress files for both the Windows and the Mac system. 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. " Click "OK" and you'll notice that the files in Windows Explorer show a dot and group of three letters after their names. That dot and group of three letters is known as an "extension," and the extension explains what kind of file it is. A file could be a plain text file, an image, a sound, a video, or program. In order to fix that problem, the user would have to download an updated version of the shared file (which to say the least - is not an easy thing to find or do). Sometimes, errors occur because a system doesn't have the required drivers or the drivers that are on the system are the incorrect version.