PDA Basics
The idea of making a small hand-held computer for storing addresses and phone numbers, taking notes and keeping track of daily appointments originated in the 1990s, although small computer organizers were available in the 1980s. One of the first PDAs that was commercially available was Apple Computer's Newton Message Pad. The Newton was too big, expensive and complicated, and its handwriting recognition program was poor. Other companies attempted to make a PDA with little success.

In 1996, the original Palm Pilot was introduced, and it was a hit with consumers. It was small and light enough to fit in a shirt pocket, ran for weeks on AAA batteries, was easy to use and could store thousands of contacts, appointments and notes. Today, you can buy Palm-like devices from major PC hardware manufacturers (Hewlett-Packard, IBM, Compaq, Sony). Though originally intended to be simple digital calendars, PDAs have evolved into machines for crunching numbers, playing games or music and downloading information from the Internet. All have one thing in common: They're designed to complement a desktop or laptop computer, not replace one.

The parts that can make up a PDA

PDAs fall into two major categories: hand-held computers and palm-sized computers. The major differences between the two are size, display and mode of data entry. Compared to palm-sized computers, hand-held computers tend to be larger and heavier. They have larger liquid crystal displays (LCD) and use a miniature keyboard, usually in combination with touch-screen technology, for data entry. Palm-sized computers are smaller and lighter. They have smaller LCDs and rely on stylus/touch-screen technology and handwriting recognition programs for data entry.