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PDA and SmartphoneThere are other requirements on the operating system for mobile devices like PDAs or smartphones as for the operating on a PC. The operating system usually takes over the tasks of the BIOS and has to be designed to run on processors with low clock frequency and few main memory. Various techniques to save energy and short reaction times are high demands on the design of the operating system. PDAs (Personal Digital Assistant) are small portable computers which can accomplish quite certain tasks and take on the role of a personal assistant. They usually consist of a ROM for the operating system and RAM from 2 to 32 mbyte and above, a docking station to power loading and the data synchronization as well as pen and/or keyboard for the character input. Other expressions for PDAs are handheld, pen computer or palmtop. Market leader is PalmOS with the greatest market share (75% according to IDC, June 2000), EPOC and Windows CE with the smallest market share. There also are models like the PowerPlay III PDA with Linux as operating system, Motorola A760 or the Sharp Zaurus SL-5500.
Typical task fields for PDAs are e-mail, WAP, text writing, date manager, calculating machines and the access to the world wide web alternatively with IrDA or special modem. The data synchronization is particularly important with the PC to load new software serially, by USB or infrared. Depending on model and equipment of a Smartphone the data interchange and internet access is available over IrDA, UMTS, Bluetooth and WLAN. The view of photos, play of music and video files (WAV, WMA, AAC, MP3, MPEG4, 3GP file formats) with stereo sound, an integrated digital camera as well as USB connection also are made useable by the operating system. For the telephony the devices offers Tri band (900 MHz, 1800 MHz, 1900 MHz) into the mobile telephone network. The user can made input with his speech, a touch screen and the keyboard. The displays support high-resolution colour rendition with resolutions of approximately 640x480 pixels, processors with more than 500 MHz of clock frequency, ROM with 128 mbyte and main memory of 64 mbyte. Motorola offers mobile telephone models with Symbian OS, Linux or Windows as the operating system.
Apple had released his own first PDA model Newton in 1991 on the market with NewtonOS as operating system. But the great market success failed to appear and the device was abandoned. Hewelett Packard His published her first PDA model named HP 95 LX on April 23rd, 1991. As software MS DOS 3.22 and Lotus Notes 1-2-3 was used. The memory was equipped with 512 kbytes RAM and 1 mbyte ROM. The LCD display was 248 x 128 pixel in size. HP released the PDA model 620 LX in 1998 which is equipped with Windows CE 2.0 and 16 mbyte of RAM. The LCD display makes 256 colours possible and features a microphone and soundspeaker.
Apple Macintosh owners can exchange data with the Palm. Office documents of a PC must be converted into a compatible format at the PDA before the use.
(2000, Palm OS 3.5)
HP Jornada 545
(2001, Windows CE 3.0)