An Introduction to File Extensions
Windows (and possibly other operating system) makes it difficult for new computer users to see the extension in order to be more user-friendly. We’re going to assume that hiding extensions is user-friendly because it’s impossible to think of any other reason. There is nothing to be gained from seeing an extension. However, there are many lessons that could be learned. This article can help you understand some of the most common extensions.
However, before you can see file extension files, you have to enable them. Open Windows Explorer. Click on the “Tools” menu and then select “File Options.” Click the “View tab” and uncheck the box next “Hide file extension for known file types.” After clicking “OK”, you will see Windows Explorer files show a dot, group of three letters and their names. The “extension” is the name for the file type. It is composed of a dot or group of three letters.
An extension can be either a plain text file or an image. However, without the extension you won’t know unless double-clicking on it. Below is a list of some of the most commonly found extensions on your computer.
.au is an extension that indicates a sound-file. These files are compatible with sound players.
.art – This extension refers to an image file compressed using AOL technology (America Online). Internet Explorer and AOL can both display this type of file. Internet Explorer, however, will not display it if AOL has been installed on your computer.
.avi is an extension that indicates a video file compatible with most multimedia viewers such as Microsoft’s Media Player.
.bmp – This extension refers to another image file that could have originated from Windows Paint.
.dll – This extension refers to a Dynamic Link Library that may contain additional software code. Many programs often share Dynamic Link Libraries. There will be a lot of them in the Windows/System Directory (but do not delete them).
.exe is the extension for a program, such as Microsoft Word or Outlook Express. You should be cautious when downloading.exe files from Internet. Malicious programmers love to hide virus in these types files.
.gif – This extension refers to another image file. It stands as “Graphics Interchange Format.” .Gif file sizes are typically smaller than those of.bmp, and they’re often found on Internet websites.
.jpg is an extension that indicates another image file. This extension stands for “Joint Photographers Experts Group”. Similar to the.gif, it is often found on Internet pages. However, it is smaller than both.gif and.bmp images.
.mid is the extension for a sound file made with a Musical Instrument Digital Interface. Windows Media Player will open these files and allow you to run them. However, they do not sound like normal.wav files or.mp3 (described later). .Mid file are used to create synthetic sounds with a computer’s audio card.
.mp3 – This extension denotes a sound file which reproduces vocal and/or musical sounds. Windows Media Player can open and run such a file.
.scr – This extension denotes a screen saver.
.sit – This extension refers to a Macintosh StuffIt archive file. Without a special utility, they won’t open on Windows.
.ttf is an extension that indicates a font specially designed for Windows. It stands to represent “True Type Font.”
.txt: This extension denotes a plain-text file that can easily be opened with Notepad.
.wav – This extension denotes a sound that, like the.mp3 files, can be opened in Windows Media Player and Windows Sound Recorder. .Wav files can be much larger than.mp3 file.
.zip – This extension refers to a Windows archive WinZip. They won’t open on a Macintosh without a special utility.
