One of the most used platforms designed for mobile devices and smartphones is the Symbian OS. The company that has designed it and which markets it is Nokia. The C++ programming language has been used to write the source code for the symbian OS. The symbian OS belongs to the mobile operating systems family.
Symbian OS is designed for pre-emptive multi-tasking and memory protection. The integrity and security of the user’s data is a primary principle considered in the design of the operating system. Also, it is designed with a perspective to save the time of the user. The OS is programmed in a manner to conserve resources by using descriptors and cleanup stack.
The basic structure of the symbian OS is classified into 5 different layers. The topmost layer is the UI framework layer. A large volume of user interface code is stored in this layer. The next layer from the top is the Application services layer that contains the Java ME. OS services layer forms the next level of the classification. The networking, telephony and file system services are placed in this layer along with the multimedia and graphics service. The symbian OS also has a large network and communication subsystem present here. The file server and user library are stored in the base services layer. There is a plug-in framework that manages the entire plug-ins. The store, DBMS, central repository and cryptographic services are also included in the base services layer. It is the lowest level reached by any user operations. The last layer is the kernel services and hardware interface layer that has microkernel architecture. Scheduler, memory management and device drivers operate through this layer.
The Symbian OS is a platform that is easy to use and understand for the user. It has a very systematic design and structure. These features work as an advantage for the market share of the operating system and make it undoubtedly the most sold operating system in global environment.
