Operating system support for multimedia: the programming model matters

Multimedia is an increasingly important part of the mix of applications that users run on personal computers and workstations. The requirements placed on a multimedia operating system are demanding and often conflicting: untrusted, independently written soft real-time applications must be able to coexist without interfering with each other. This must be accomplished while requiring as little extra effort as possible from application developers, and the resulting system must be usable and understandable by end users even when application resource requirements exceed system capacity. This article analyzes the goals of multimedia schedulers and provides a taxonomy of techniques used to achieve them; representative schedulers are classified and characterized in terms of the things that they make easy and hard, including the associated programming tasks. This is done to support our principal contribution: an analysis of usability issues and tradeoffs in multimedia scheduling for both application developers and end users.