Symbian OS is widely used in multiple smartphone platforms, such as Series 60, Series 80 and Series 90, three of the UI platforms from Nokia, and UIQ (the UI platform from UIQ Technology).
Series 60 SDKs are built upon specific versions of Symbian OS C++ SDKs released by Symbian. An SDK contains a wide range of tools, APIs, libraries and documentation to enable you to develop new applications, typically as after-market applications.
As a developer you may need to work with SDKs for more than one version of Series 60 (or even SDKs for different Symbian OS UI platforms). The most important issue is to select the correct SDK version for your chosen Series 60 product.
Nokia or Series 60 Licensees release SDKs that are suitable for development for a specific version of Series 60 Platform. That is to say, each Series 60 product is based on a particular release of the platform, and SDK releases are made to be suitable for development for a platform version. A particular SDK release may also be suitable for use with earlier versions of the platform as well. Such "backward compatibility" will depend on the version of the Symbian OS used as the basis of the release, the APIs used by the application developer and any changes that have occurred in those APIs between platform releases. Particular Licensees also may introduce additional product-specific APIs to allow developers to access the features that differentiate their Series 60 product from those from other Licensees. For example, the Siemens SX1 smartphone includes an FM radio, so the relevant SDK may include "add-on" APIs to manipulate the radio. For maximum compatibility across different Licensee products you may want to avoid using such product-specific APIs. You may even choose to limit your use of the general APIs to those that are common and unchanged across a selected range of platform versions.
You will find the key differences between releases of Series 60 Platform described in broad detail in the Introduction to this book.
More extensive variants of Series 60 Development Platforms are available to Licensees, Competence Centers, and other software and technology partners to allow them to develop at the system level, rather than at the application level. This book, however, will focus on the publicly available SDKs.
Using a single Symbian OS SDK is very easy, and the installation process will prepare it for immediate use. However, developers often need to work with SDKs for different versions of Series 60, or even SDKs for different user interface (UI) platforms. As described in Chapter 2, you can install multiple SDKs on your development PC, with a few restrictions on where they can be installed and how they are selected for use.