Symbian OS used by different suppliers of mobile communications equipment are varied. Changes in the implementation of the Symbian OS hardware may be possible because the operating system has an application programming interface (Application Programming Interface: API). API support for communication and behavior are common in the material that can be used for objects of other applications. This could be because the API is an interface object defined at the application level, which contains the procedures and functions (and variables and data structures) that manage / use the kernel, where the connection between software and hardware. With the standard API allows developers to make adjustments in an application designed to be installed on mobile products in variety.
As the desktop operating system, Symbian capable of operating at multi-tasking operating system, multi-tasking and memory backup. Symbian and all programming is done on the basis of events, which means that the hardware processor becomes inactive when no input in the form of a particular activity. However, one must understand the operating system designed for installation on mobile devices with limited resources. Multithreaded and multitasking Symbian OS provides the ability to run multiple applications simultaneously. But this feature, the preemptive multitasking kernel will give everyone a treatment program for time division switching is achieved by so quickly that it appears to the user as if the process runs simultaneously. As defined in terms of programming of specific priorities to determine which processes are running in the first place and that the next process and how much time will be given.
Symbian OS itself is not the nature of open source software in its entirety, because despite the availability of APIs and documentation, which helped the developers to create software applications that run on that operating system, released to the public, but not for your own source code.
