Portable Document Format (PDF)
PDF files are most commonly used to encode the exact look of a document in a device-independent way. This means that no matter what type of computer they are viewed from, they should be displayed the same way.
PDF files require a special program to open them. This most popular such program is Adobe Acrobat Reader. Adobe Acrobat Reader is a very user friendly program, but it is also quite large, and may take over an hour to download on a dialup connection. Foxit Reader is a much smaller alternative (less than 1/25 the size) and is suitable for most tasks, although it lacks some of Abobe Acrobat Reader's more advanced features.
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