Symbian History
Symbian OS started life as EPOC - the operating system used for many years in Psion handheld devices. When Symbian was formed in 1998, Psion contributed EPOC into the group. EPOC was renamed Symbian OS and has been progressively updated, incorporating both voice and data telephony technologies of ever greater sophistication with every product release.
Abstract
Symbian OS is designed for the mobile phone environment. It addresses constraints of mobile phones by providing a framework to handle low memory situations, a power management model, and a rich software layer implementing industry standards for communications, telephony and data rendering. Even with these abundant features, Symbian OS puts no constraints on the integration of other peripheral hardware. This flexibility allows handset manufacturers to pursue innovative and original designs. Symbian OS is proven on several platforms. It started life as the operating system for the Psion series of consumer PDA products (including Series 5mx, Revo and netBook), and various adaptations by Diamond, Oregon Scientific and Ericsson. The first dedicated mobile phone incorporating Symbian OS was the Ericsson R380 Smartphone, which incorporated a flip-open keypad to reveal a touch screen display and several connected applications. Most recently available is the Nokia 9210 Communicator, a mobile phone that has a QWERTY keyboard and color display, and is fully open to third-party applications written in Java or C++.
Object Oriented Design
Because Symbian OS has an object oriented design, it is easy to configure for different sorts of hardware, and being component based, it allows manufacturers to add or remove components. This id crucial in enabling manufacturers to make devices that best suit their customers needs. This flexibility extends even to the user interface - again allowing a variety of different device designs to work from the same operating system. For Symbian itself, the design allows new technology to be slotted into an already stable platform. This will provide a stable base as the telecommunications industry moves from 2G to 2.5G to 3G to 4G, with the further introduction of new technologies such as SyncML, BlueTooth, Multimedia Messaging amongst many. The picture will grow ever more complicated, especially when technologies are used in combination, but Symbian OS is ready!. For application developers, this separation of components allows them to program far richer applications - getting into the middle of the operating system.
Client-Server Architecture
The power of the client-server framework is widely acknowledged in the software community. In Symbian OS, clients are programs that have user interfaces, and servers are programs that can only be accessed via a well defined interface from other programs. The role of a client is to serve the user, while servers ensure timely response to all the clients while controlling the access to the resources of the actual system. Additionally, in practice, one server will often have many extra servers relying on the original serve.
Application Architecture
Symbian OS has an application architecture that helps developers manage the complexity of graphical user interface based applications. A Symbian OS application is made up of several parts. An Application Engine that contains all the non-UI parts of an application, an Application UI that handles the application events coming from the user and calls the Engine, and then there is the Application View(or several views) which contains the actual windows and controls(eg. buttons, text an graphics) that show on the screen of a Symbian OS device. The Application Architecture has a built in Active Scheduler so that developers don't need to understand the ins and outs of the Active Object system when writing normal applications.
Introduction
Small devices come in many shapes and sizes, each addressing distinct target markets that have different requirements. The market segment we are interested in is that of the mobile phone. The primary requirement of this market segment is that all products are great phones. This segment spans voice-centric phones with information capability to information-centric devices with voice capability. These advanced mobile phones integrate fully-featured personal digital assistant (PDA) capabilities with those of a traditional mobile phone in a single unit. There are seeral critical factors for the need of operating systems in this market. It is important to look at the mobile phone market in isolation. It has specific needs that make it unlike markets for PCs or fixed domestic appliances.
Conclusion
Symbian OS is a robust multi-tasking operating system, designed specifically for real-world wireless environments and the constraints of mobile phones (including limited amount of memory). Symbian OS is natively IP-based, with fully integrated communications and messaging.
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