A PDA is a mobile phone offering advanced capabilities, often with PC-like functionality (PC-mobile handset convergence). Currently, a typical PDA has 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. A common feature of PDA is the integration of Data Capture devices like Bar Code, RFID and Smart Card Readers.
Operating systems that can be found on smart phones include Symbian OS, iPhone OS, RIM's BlackBerry, Windows CE 5.0, Windows Mobile 6.5., Palm WebOS and Android. Android and WebOS are in turn built on top of Linux, and the iPhone OS is derived from the BSD and NeXTSTEP operating systems, which all are related to Unix.