Insider Power Techniques for Microsoft® Windows® XP

Getting Familiar with File Types

A document’s file type is determined by the extension used in its file name, and it defines which actions you can perform on the document. For example, a text document—that is, a document with a name that ends with .txt—has two actions: Open, which displays the document in Notepad; and Print, which sends the document to the Windows XP default printer. (Technically, the Print action opens Notepad, loads the document, selects File, Print, and then closes Notepad. This all happens in the blink of an eye.) Each file type has a default action that runs when you double-click a document of that type. (For text files, the default action is Open.) When a file name is selected in Windows Explorer, the default action appears ...