The Symbian platform, is a comprehensive open-source software platform for Symbian-based devices. The platform is used by device manufactures to build devices, and by third-party developers to create after-market applications for those Symbian devices.
The Symbian platform includes a customizable user interface, a rich set of applications, common user interface components (AVKON and Qt Quick ) and development tools for implementing new applications. It also includes tools and documentation that enables device creators and application developers to create feature-rich devices and applications.
The Symbian platform architecture is divided into different layers:
The Applications Layer consists of application-specific UI and engine components. It uses the services provided by Middleware and OS layers.
The Middleware Layer consists of domains which provide services to the application layer; for example, Multimedia, Networking and Location services.
The Operating System (OS) Layer provides all higher-level OS services across a full range of technology domains such as communications, networking, graphics, multimedia and so on. It also includes low-level OS services such as frameworks, libraries and utilities, which turn the abstracted hardware and OS mechanisms into a programmable interface.
The Adaptation layer integrates the generic platform software with the phone’s cellular platform. It is implemented by the device creators though reference implementations are provided with the platform.
The Cellular Platform is the device-specific hardware and cellular software that performs the services required by the Symbian platform.
Figure: Architecture of the Symbian platform
The latest platform release, Symbian Belle, brings a whole new user experience with the renewed user interface, better navigation controls, improved status bar, and much more. For a brief introduction to this release and the devices running on it, refer to Symbian belle.
Symbian Belle also needs a change in the way developers have been looking at the Symbian UI, as the UI is not the same anymore. The UI changes in Symbian Belle are detailed in the UI style guide to help the developers understand and adapt to them in their applications.
The platform UID for Symbian Belle is 0x2003A678.
For information on the platform UID for different Symbian versions, refer S60 Platform and device identification codes
You can download the Nokia Symbian Belle SDK from Nokia Developer website.