term File Types
describes the collection of associations between documents and the
applications that use them. The most apparent use of this feature is
that, for example, Windows knows to run Notepad when you double-click
on a file with the
.txt extension. The
traditional method for configuring these associations to suit your
needs is discussed in Section 4.2.2 in
Chapter 4, but it goes quite a bit deeper
It all starts with file extensions, the letters (usually
three) that follow the period in most filenames. For example, the
extension of the file
.txt, signifying a plain text file; the
.wpd, signifying a document created in
WordPerfect. By default, Windows hides the extensions of registered
file types in Explorer and on the desktop, but it’s best to
have them displayed.
File extensions not only allow you to easily determine what kind of file a certain file is (because icons are almost never descriptive enough), but also allow you to change Windows’ perception of the type of a file by simply renaming the extension. Note that changing a file’s extension doesn’t actually change the contents or the format of the file, only how Windows interacts with it.
To display your file extensions, select Folder Options in Explorer’s Tools menu, choose the View tab, and turn off the Hide file extensions for known file-types option. Click OK when you’re done.
By hiding file extensions, Microsoft hoped to make Windows ...