Palm webOS

Palm webOS Architecture

Palm webOS is based on the Linux 2.6 kernel, with a combination of open source and Palm components providing user space services, referred to as the Core OS.

You won’t have any direct interaction with the Core OS, nor will the end users. Instead your access is through Mojo and the various services. Users interact with applications and the UI System Manager, which is responsible for the System UI. Collectively, this is known as the application environment. Figure 1-11 shows a simplified view of the webOS architecture.

Figure 1-11. Simplified webOS architecture

This overview is included as background to give you an idea of how webOS works—this information is not needed to build applications, so you can skip it if you aren’t interested.

Application Environment

The application runtime environment is managed by the UI System Manager, which also presents the System UI that is manipulated by the user. The framework provides access to the UI widgets and the Palm webOS services. Supporting this environment is the Core OS environment, an embedded Linux OS with some custom subsystems handling telephony, touch and keyboard input, power management, storage, and audio routing. All these Core OS capabilities are managed by the application environment and exposed to the end user as System UI and to the developer through Mojo APIs.

Taking a deeper look at the webOS architecture, ...