A personal digital assistant (PDA) is a handheld computer also known as small or palmtop computers. Newer PDAs also have both color screens and audio capabilities, enabling them to be used as mobile phones, (smartphones), web browsers, or portable media players. Many PDAs can access the Internet, intranets or extranets via Wi-Fi, or Wireless Wide-Area Networks (WWANs). Many PDAs employ touch screen technology. Typical features
Currently, a typical PDA has a touch screen for entering data, a memory card slot for data storage and at least one of the following for connectivity: IrDA, Bluetooth and/or WiFi. However, many PDAs (typically those used primarily as telephones) may not have a touch screen, using softkeys, a directional pad and either the numeric keypad or a thumb keyboard for input.
Software typically required to be a PDA includes an appointment calendar, a to-do list, an address book for contacts and some sort of note program. Connected PDAs also typically include E-mail and Web support.
Touch screen
PalmPilot, 1998
Many original PDAs, such as the Apple Newton and the Palm Pilot, featured touch screens for user interaction, having only a few buttons usually reserved for shortcuts to often used programs. Touch screen PDAs, including Windows Pocket PC devices, usually have a detachable stylus that can be used on the touch screen. Interaction is then done by tapping the screen to activate buttons or menu choices, and dragging the stylus to, for example, highlight. Text input is usually done in one of four ways:
Using a virtual keyboard, where a keyboard is shown on the touch screen. Input is done by tapping letters on the screen.
Using external keyboard or chorded keyboard connected by USB, IR or Bluetooth.
Using letter or word recognition, where letters or words are written on the touch screen, and then "translated" to letters in the currently activated text field. Despite rigorous research and development projects, end-users experience mixed results with this input method, with some finding it frustrating and inaccurate, while others are satisfied with the quality.[1] Recognition and computation of handwritten horizontal and vertical formulas such as "1 + 2 =" was also under development.
Stroke recognition (termed Graffiti by Palm). In this system a predefined set of strokes represents the various characters needed. The user learns to draw these strokes on the screen or in an input area. The strokes are often simplified character shapes to make them easier to remember.
PDAs for business use, including the BlackBerry and Treo, have full keyboards and scroll wheels or thumb wheels to facilitate data entry and navigation, in addition to supporting touch-screen input. There are also full-size foldable keyboards available that plug directly, or use wireless technology to interface with the PDA and allow for normal typing. BlackBerry has additional functionality, such as push-based email and applications.
Newer PDAs, such as the Apple iPhone and iPod touch include new user interfaces using other means of input. The iPhone and iPod touch uses a technology called Multi-touch.
Currently, a typical PDA has a touch screen for entering data, a memory card slot for data storage and at least one of the following for connectivity: IrDA, Bluetooth and/or WiFi. However, many PDAs (typically those used primarily as telephones) may not have a touch screen, using softkeys, a directional pad and either the numeric keypad or a thumb keyboard for input.
Software typically required to be a PDA includes an appointment calendar, a to-do list, an address book for contacts and some sort of note program. Connected PDAs also typically include E-mail and Web support.
Touch screen
PalmPilot, 1998
Many original PDAs, such as the Apple Newton and the Palm Pilot, featured touch screens for user interaction, having only a few buttons usually reserved for shortcuts to often used programs. Touch screen PDAs, including Windows Pocket PC devices, usually have a detachable stylus that can be used on the touch screen. Interaction is then done by tapping the screen to activate buttons or menu choices, and dragging the stylus to, for example, highlight. Text input is usually done in one of four ways:
Using a virtual keyboard, where a keyboard is shown on the touch screen. Input is done by tapping letters on the screen.
Using external keyboard or chorded keyboard connected by USB, IR or Bluetooth.
Using letter or word recognition, where letters or words are written on the touch screen, and then "translated" to letters in the currently activated text field. Despite rigorous research and development projects, end-users experience mixed results with this input method, with some finding it frustrating and inaccurate, while others are satisfied with the quality.[1] Recognition and computation of handwritten horizontal and vertical formulas such as "1 + 2 =" was also under development.
Stroke recognition (termed Graffiti by Palm). In this system a predefined set of strokes represents the various characters needed. The user learns to draw these strokes on the screen or in an input area. The strokes are often simplified character shapes to make them easier to remember.
PDAs for business use, including the BlackBerry and Treo, have full keyboards and scroll wheels or thumb wheels to facilitate data entry and navigation, in addition to supporting touch-screen input. There are also full-size foldable keyboards available that plug directly, or use wireless technology to interface with the PDA and allow for normal typing. BlackBerry has additional functionality, such as push-based email and applications.
Newer PDAs, such as the Apple iPhone and iPod touch include new user interfaces using other means of input. The iPhone and iPod touch uses a technology called Multi-touch.
