Components on the desktop

We report on our experiences with developing KOM, a component model for the K Desktop Environment (KDE), the most popular graphical desktop environment for Linux and other Unix systems. The paper focuses on two major subjects: (1) the design of the KOM component model and (2) the suitability of CORBA for such an environment. We describe the requirements and the new design patterns introduced by KOM, especially the signals&slots and actions pattern, and the trade-off between a clear design and aspects like memory usage, speed and practicability. KOM supports the distribution of components over the network and language independence. To achieve this, the first version of KOM was based on CORBA, while for the latest version CORBA was replaced by a new communication protocol especially designed for KDE. We show the problems and implications of using CORBA as a basis for a component model in a desktop oriented project like KDE.