I have two friends named Mary. One lives in Canada, the other in the States. The one in Canada hates baseball but loves Lacrosse, the other can’t stand hockey but could live at the baseball diamond. But because they both have the same name, how am I to know who likes what? Well, a neat little idea hit me. I’ve marked one as Mary.us in my address book, and the other as Mary.ca. That way I can send emails about Lacrosse to Mary.ca and emails about baseball to Mary.us.
The same goes for file names on your computer. Every file on your computer has a name and what they are called is extremely important. Every file that exists on your computer has a function that only it can do. How do you know which file does what? Just like the above example, every file on your computer has what we call a file extension. The extension usually consists of 3 or 4 letters or numbers that follow a period after the main part of the file name. For example, you make have a file called “accounts jan 2003.doc” or a picture called “mary and jim.jpg”. This extension tells the computer what kind of file it is and what program is needed to run it, view it, or work with it in some way. To be able to open a file on your computer, a file must have a program associated with it.
The most common file extension that most people will be familiar with is “.doc”. This file extension tells the computer that it’s a Microsoft Word or Wordpad document. When a file has this extension it can only be properly viewed by Microsoft Word, Wordpad, or the Microsoft Word Viewer (available for download at the Microsoft website, if you’d like to go and hunt it down. Call us if you need help finding it.)
Another common file extension is “.exe”. This says that the file is an executable program that you can run. If you are reading this article in Internet Explorer then a file called “IEXPLORE.EXE” was started to let you view the web page. When you double-click this file, or type it in at the Start/Run line, it will open the program described in its file name.
Back in the old DOS days, file names couldn’t have more than 8 characters for the name, and no more than 3 characters for the file extension. This made it a real challenge to figure out what the file was used for and what program was needed to access it. It created a very cryptic set of filenames. Instead of being able to call something “Jan 2003 county records memo to councellors.doc” you had something like “crm-j03.doc”. Not the easiest thing to figure out what it’s for. These days in Windows, you can have entire sentences for the file name and more than 3 characters for the extension if you so choose. This makes it a lot easier to tell what the file is and what is needed to run it.
Most of you will probably not be able to see the file extensions at the moment. Microsoft, in it’s infinite wisdom, has it turned off by default. The easiest way to turn it back on again is to open the “My Documents” window and go to “Tools” on the menu bar at the top (if you can’t see “tools” you have a slightly older version of windows and you’ll be able to find it under “View”). In there you should find “Folder Options”. When you click on “Folder Options”, you’ll see a new dialog box with “General”, View”, and “File Types” across the top. Click on “View.” In there, look in the list for “Hide file extension for known file types” and turn it off. When you click OK at the bottom of that box, you’ll be able to see the file extensions properly.