File Extensions and File Associations

Computer Files have varying file extensions. File Extensions can be hidden or shown, depending on your settings. An example of a file extension? Have you ever heard of a "jpg" or a "rtf" file? jpg (or jpeg) files are image files, and rtf (Rich Text Format) files are text documents that can be read by most word processors, including word, works, and word pad. A file name followed by a .doc extension is USUALLY a Microsoft Word Document. A gif document (Graphics Interchange Format) is an image file that can show transperency.

Each document or file has a file extension. If you have a word document, and you save it as "Christmas Card Addresses", your full filename, including the file extension, would be:

• Christmas Card Addresses.doc

Many programs, including word, allow you to save files in several different formats. If you use Adobe Phoshop, and create a logo or graphic, you could save it as a Photoshop Document, which supports layers and has a psd extension. Or you could save it as a jpg, gif, tiff, or png format, or one of about 14 other file extensions.

A File extension always follows the document name, after a period.

How about file associations? It's best to understand file extensions before you ask about file associations. A file association is the method that Microsoft Windows Operating Systems use to determine what program will open what type of file extension. If you have Windows Picture and Fax Viewer, you may have it set as your default viewer for jpg and gif (image files.) Windows looks at your file extension and then matches it up to the appropriate program.

Let's talk about an example of file association, in the Simplest of terms. An HTML document contains text and code that makes up a webpage. When viewing a webpage, you can use any variety of programs, called "Web Browsers." Web Browser examples: Internet Explorer, Mozilla Firefox, Safari, Netscape, and Opera. Each of these programs interprets or reads the code and displays it in the webpage format that we have grown so fond of.

Sometimes when you open a program, like Internet Explorer, it may give you a message (see below) stating "Internet Explorer is not currently your default browser. Would you like to make it your default browser?"
If you answer YES to this question, windows automatically sets the program Internet Explorer as the program that opens HTML files. That is how IE becomes your default browser. If Mozilla asks you the same questions, and you answer yes, Windows will set Mozilla Firefox as the default program to open HTML Files.

This is all just a "file association," associating the file extension HTML to the program Internet Explorer. When you install Microsoft Office, it automatically associates the "doc" extension to the program Microsoft Word. It associates the "xls" extension to Microsoft Excel, and the "eml" extension (email document) is often associated with Microsoft Outlook, if not when installed, when Outlook is opened for the first time. You will be asked "Do you want to make Microsoft Outlook your default email client?" and if you answer yes, the file association "magically" takes place. This is how, when you click on an email address on the web, Windows automatically knows to open Microsoft Outlook or Outlook Express, to start a new email message. All of this is determined by file association.

Some of you may have experienced problems, like we discussed in our meeting in February, with files opening with a program that you don't WANT them to open with. There are many ways to change file associations, or to work around the problem, and I will share with you the two simplest ways.

1. Right click on the file that you want to open. Choose "Open With" and then "Choose Program." This will pop open a new window, from which you can choose the program you wish this file to open. If you want this to be a permenant change, you can check the box that says "always use the selected program to open this kind of file" and it will change the file association for you.
2. Open the PROGRAM first, then do a file/open and browse for the file. This is a one time work-around and will not change the file association, but will open the file in the program you chose.

There is another method to go directly to your file associations and change them. Older versions of windows (Windows NT, ME, 98, 95, and older) contained a file called "win file.exe"
Which is a file extension/association manager. I do not recommend that just anyone go into winfile.exe and monkey around, but if you have more advanced computer skills, google winfile.exe or read more about Winfile at Wikipedia.