Developing Software for Symbian OS: A Beginner's Guide to Creating Symbian OS v9 Smartphone Applications in C++

Chapter 3. Symbian OS Architecture

This chapter gives an overview of the architecture of Symbian OS — its main components and its underlying functionality.

Much of the functionality described in this chapter is transparent from a typical Symbian OS application programming view; however, understanding the architectural details of an operating system can be useful in developing software for it — especially for programming on highly reliable, limited-resource devices such as smartphones.

You can skim this chapter on a first read if you want, since an understanding of many of the subjects here is not absolutely essential to developing applications. But if you are like me and prefer to dig into the details in order to gain deeper knowledge, then you will find this chapter useful.

Components in Symbian OS

There are usually many ways to slice a system up into pieces — the following breakdown of the major parts of Symbian OS is suitable for the detail covered in this chapter:^[2].

• Kernel

  The kernel is the central manager and arbiter of Symbian OS. It manages the system memory and schedules programs for execution. It also allocates shared system resources and handles any functionality that requires privileged access to the CPU.

• Base libraries: user library, file system, database manager

  The user library (euser.dll) contains APIs that provide functionality such as string manipulation, linked lists, containers, math functions, error handling, and timers. The user library also provides 'user-side' access ...