A personal digital assistant (PDA) is a multi-purpose mobile device which functioned as a personal information manager. Following a boom in the 1990s and 2000s, PDAs were mostly displaced in the early 2010s by the widespread adoption of smartphones and tablet computers. In particular, smartphones based on iOS and Android took their place, causing a rapid decline in PDA usage. A PDA had a flat-screen display; many later PDAs also had color displays, and instead of navigation buttons, resistive touchscreens, or even capacitive touchscreens. Most models also had audio capabilities, allowing usage as a portable media player, and also enabling some of them to be used as telephones. By the early 2000s, nearly all PDA models had the ability to access the Internet via Wi-Fi; these models generally included a web browser. The concept of the PDA was eventually combined with that of the cell phone, the camera, and the GPS navigation system to produce the smartphone. To a lesser extent, the tablet computer also replaced PDAs, offering larger screens and newer operating systems.
History
The first PDA, the Organiser, was released in 1984 by Psion, followed by Psion's Series 3, in 1991. The latter began to resemble the more familiar PDA style, including a full keyboard. The term PDA was first used on 7 January 1992 by Apple Inc. CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevada, referring to the Apple Newton.
In 1994, IBM introduced the first PDA with analog cellular phone functionality, the IBM Simon, which can also be considered the first smartphone. Then in 1996, Nokia introduced a PDA with digital cellphone functionality, the 9000 Communicator. Another early entrant in this market was Palm, with a line of PDA products which began in March 1996. Palm would eventually be the dominant vendor of PDAs until the rising popularity of Pocket PC devices in the early 2000s. By the mid-2000s, most PDAs had morphed into smartphones as classic PDAs without cellular radios were increasingly becoming uncommon. Devices such as the Palm Treo (resembling a bar phone) and the Kyocera 7135 (resembling a traditional flip phone) began merging the concept on a PDA with the concept of a cell phone. Some such devices even had built-in cameras and/or GPS capabilities, making them resemble smartphones more than PDAs.
Typical features A typical PDA has a touchscreen for navigation, a memory card slot for data storage, and IrDA, Bluetooth and/or Wi-Fi. However, some PDAs may not have a touchscreen, using soft keys, a directional pad, and a numeric keypad or a thumb keyboard for input. To have the functions expected of a PDA, a device's software typically includes an appointment calendar, a to-do list, an address book for contacts, a calculator, and some sort of memo (or "note") program. PDAs with wireless data connections also typically include an email client and a Web browser, and may or may not include telephony functionality.
Touchscreen
Many of the original PDAs, such as the Apple Newton and Palm Pilot, featured a touchscreen for user interaction, having only a few buttons—usually reserved for shortcuts to often-used programs. Some touchscreen PDAs, including Windows Mobile devices, had a detachable stylus to facilitate making selections. The user interacted with the device by tapping the screen to select buttons or issue commands, or by dragging a finger (or the stylus) on the screen to make selections or scroll. Typical methods of entering text on touchscreen PDAs included:
A virtual keyboard, where a keyboard is shown on the touchscreen. Text is entered by tapping the on-screen keyboard with a finger or stylus. An external keyboard connected via USB, Infrared port, or Bluetooth. Some users may choose a chorded keyboard for one-handed use. Handwriting recognition, where letters or words are written on the touchscreen, often with a stylus, and the PDA converts the input to text. Recognition and computation of handwritten horizontal and vertical formulas, such as "1 + 2 =", may also have been a feature. Stroke recognition allowed the user to make a predefined set of strokes on the touchscreen, sometimes in a special input area, representing the various characters to be input. The strokes were often simplified character shapes, making them easier for the device to recognize. One widely known stroke recognition system was Palm's Graffiti. Despite research and development projects, end-users experienced mixed results with handwriting recognition systems. Some found it frustrating and inaccurate, while others were satisfied with the quality of the recognition. Touchscreen PDAs intended for business use, such as the BlackBerry and Palm Treo, usually also offered full keyboards and scroll wheels or thumbwheels to facilitate data entry and navigation. Multiple touchscreen PDAs supported some form of external keyboard as well. Specialized folding keyboards, which offer a full-sized keyboard but collapse into a compact size for transport, were made available for multiple models. External keyboards may have attached to the PDA directly, using a cable, or using wireless technology such as infrared or Bluetooth to connect to the PDA. Newer PDAs, such as the HTC HD2, Palm Pre, Pre Plus, Pixi, and Pixi Plus, as well as devices running the Android operating system, included more advanced forms of touchscreen that could register multiple touches simultaneously. These "multi-touch" displays allowed for more sophisticated interfaces using various gestures entered with one or more fingers.
Memory cards Although many early PDAs did not have memory card slots, later models had either some form of Secure Digital (SD) slot, a CompactFlash slot or a combination of the two. Although designed for memory, Secure Digital Input/Output (SDIO) and CompactFlash cards were made available that provided peripheral accessories like Wi-Fi or digital cameras to devices with software support. Some PDAs also had a USB port, mainly for USB flash drives. Some PDAs used microSD cards, which are electronically compatible with SD cards, but have a much smaller physical size.
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