Interprocess communication (IPC) provides the fundamental mechanism for the Mach microkernel to be extensible and flexible. Mach IPC provides efficient communication mechanisms for many applications. However, it does not provide sufficient functionality for real-time applications which have rigid timing constraints among threads. In RealTime Mach (RT-Mach), we have extended Mach IPC to be priority inversion free for real-time applications. This paper describes the Real-Time IPC (RT-IPC) facilities, its implementation, and the evaluation results. We used the Distributed Hartstone (DHS) real-time benchmark for the evaluation and the results show that RT-IPC can reduce priority inversion and improve CPU utilization for real-time applications. 1. Introduction In traditional operating systems, it is difficult to support real-time applications such as continuous media applications and mobile computing, due to the lack of facilities which can manage time constrained resources, such as proce...

M icrokernel technology is a well recognised technology for building operating systems. Recently there has been some experimentation in the area of building distributed object-support platforms on top of microkernels. This thesis presents the design of the core kernel components of such a platform. These kernel components form the nucleus of this platform. The nucleus is designed to be an extensible minimal support layer for distributed object-support run-time systems. The platform is being used as a basis for extensive research on a number of topics in distributed systems. The support layer provides a communications system, a name service, a distributed threads package, an object fault handler and a location service. The design of the communications system provides a framework for the support of a number of different communications protocols within the one nucleus transparently to the higher levels. The communications system is heavily reliant on the name service, which provides the ...

Multimedia has generated a widespread interest in real-time support within general purpose operating systems. In addition to real-time support, multimedia often requires large amounts of data to be moved between devices and processes. The Multimedia Testbed is a set of applications that stress consistent low-latency response and efficient interprocess communication for large blocks of data. The Multimedia Testbed was ported to the Mach 3.0 Operating System where performance was measured. Experiments were conducted to compare various techniques for IPC and disk reads. Experience with fixed priority scheduling, user-level device drivers, and a high-resolution timer are also reported. This research was performed by the Carnegie Mellon Information Technology Center and supported by the IBM Corporation. Keywords: Performance Measurements, Multimedia, Real Time, Operating Systems, Interprocess Communication i Table of Contents 1. Introduction. 1 1.1. What should we expect? 1 2. Related ...