Read this text again and find the word with the following meaning in it: a special pen used as an input device on a pressure-sensitive screenA PDA (personal digital assistant) is a handheld organizer with
phone and internet capabilities. PDAs are also called palmtops and
pocket PCs.
PDAs vary in how you
input data and instructions. Some devices use a stylus to write, draw
or make selections on a touch-sensitive LCD screen. Software inside
the PDA recognizes hand-witten characters and converts them into
editable text. You can use the stylus to tap on the letters of a
miniature on-screen keyboard. In addition, many devices now include a
small QWERTY keyboard. They may also have a few buttons to launch
programs and scroll through the files.
As for the operating
system, most PDAs run on Windows Mobile or Palm OS. However,
Blackberry wireless devices use RIM, from Research in Motion, and
Nokia and Samsung smartphones use the Symbian OS. A smartphone is a
full-featured mobile phone with PDA capabilities.
Today's PDAs come
with PIM software that lets you manage such information as contacts,
appointments and to-do lists. They can be used as a radio or MP3
player, play games, record voice and video, act as GPS devices, and
connect to the Internet through Wi-F access points or cellular data
networks. Some PDAs can also run pocket versions of MS Word, Excel, a
web browser and email program.
PDA processors are
small, cheap and not that powerful. A widely used microprocessor is
ARM, based on RISC (reduced instruction set computer) architecture,
which reduces chip complexity by using simpler instructions.
PDAs store the basic programs (operating system, calendar,
calculator, etc.) in a ROM chip. The programs that you add and the
data processed are held in the RAM chips. The newest PDAs use flash
memory instead of RAM. Flash memory is non-volatile - i.e. it retains
its information when the power is off. Flash memory cards are ideal
for storing the user's favourite music, picture and video files.
Most models can
syncronize to a PC - i.e. exchange data and update it - in case you
want to access the same data on both devices. To syncronize and
transfer data, you need to connect your PDA to a standard PC via a
USB cable or wirelessly. Modern devices support two types of wireless
connection: IrDA, which uses infrared light beams similar to TV
remote controls, and Bluetooth,which uses radio waves to communicate
with Bluetooth-enabled devices (laptops, mobiles, etc.).