 the "pusedo OS" and it runs on BREW RTOS (Real time OS). Adobe's Adobe Flash Lite is also a supported user interface on BREW. Until the recent past, BREW was mainly used in devices that were available in the USA, Recently it gained a foothold in Europe via three Skype phones offered by the network 3. 3 A MIDlet is an application that uses the Mobile Information Device Profile (MIDP) of the Connected Limited Device Configuration (CLDC) for the Java ME environment. Smart Wireless Devices 10.3.9 Java ME The Java ME (Micro Edition) operation system is specifically designed by Sun Microsystems for con- sumer electronics and mobile devices. It provides a common standard namely MIDP (Mobile Information Device Profile) for writing applications in Java. Java ME is a secure and supported os that can provide a rich consumer experience. 10.3.10 REX os The REX (Real Time Executive) os is provided by Qualcomm's to the handset community. REX is used to run Qualcomm's MSM (Mobile Station Modem) chipset. REX consists of several tasks and each task performs an infinite loop code. REX switches the tasks as priority based scheduling algorithm. That is, REX controls the tasks by starting or stopping execution of them. Only handset manufacturers that have an MSM license from Qualcomm can develop the handset applications on the REX based software platform. The application development is mainly limited to the development of contents of wireless mobile Internet. The REX based software platform does not support a general interface for adding or removing applications. Further, because the REX based software platform does not support a POSIX (Portable Operating System Interface for UNIX interface), the REX based handset cannot use the open source which includes useful applications and various services based in TCP/IP. Thus, due to REX's close development environment, it is difficult to develop the new REX based handsets as compared to competitors such as Nokia [2]. Table 10.1 summarizes the key attributes of the various mobile software pla