On kernel support for real-time multimedia applications

Real-time operating system services are required to support multimedia systems that rely heavily on the workstation processor for control of the audio and video processors and movement of audio and video data. The requirements for each service are described, together with the YARTOS kernel, an operating system kernel that provides real-time communication and computation services. The programming model supported by YARTOS is an extension of Wirth´s discipline of real-time programming. In essence it is a message-passing system with a semantics of interprocess communication that specifies the real-time response that an operating system must provide to a message receiver. This allows a programmer to assert an upper bound on the time to receipt and processing of each message. The YARTOS kernel supports the notion of guaranteed processing rates. The desired processing rate of each task is made known to the kernel, and the kernel provides a guaranteed response time to each task that is sufficient for ensuring that the required processing rate is achieved