MINIX4RT: Real-time Semaphores


  • Pablo Andrés Pessolani Departamento de Sistemas, Facultad Regional Santa Fe, Universidad Tecnológica Nacional, Santa Fe, Argentina


semaphores, priority Inheritance, priority Inversion., minix, real-time


MINIX4RT is an extension of the well-known MINIX Operating System that adds Hard Real-Time services in a new microkernel but keeping backward compatibility with standard MINIX versions. Semaphores are the primitive synchronization and mutual exclusion mechanism in many operating systems, but MINIX does not provide those facilities. Semaphores were added to MINIX4RT, and since it is a Real-Time Operating System, they must meet some processing requirements such as dequeueing waiting processes in priority order and avoiding the Priority Inversion problem. This article describes the Real-Time Semaphores facilities available on MINIX4RT, its design, implementation, performance tests and their results.


Download data is not yet available.


[1] Pessolani, Pablo A, “RT-MINIXv2: Architecture and Interrupt Handling”, 5th Argentine Symposium on Computing Technology, 2004.
[2] Pessolani, Pablo A., “RT-MINIXv2: Real-Time Process Management and Scheduling”, 6th Argentine Symposium on Computing Technology, 2005.
[3] Tanenbaum Andrew S., Woodhull Albert S., “Sistemas Operativos: Diseño e Implementación” 2da Edición, ISBN 9701701658, Editorial Prentice-Hall , 1999.
[4] Pessolani, Pablo A., “MINIX4RT: Time Management and Timer Facilities”, 7th Argentine Symposium on Computing Technology, 2006.
[5] Pessolani, Pablo A., “MINIX4RT: Real-Time Interprocess Communications Facilities”, Workshop de Arquitecturas, Redes y Sistemas Operativos, XII Congreso Argentino de Ciencias de la Computación, 2006.
[6] Mark W. Borger, Ragunathan Rajkumar. “Implementing Priority Inheritance Algorithms in an Ada Runtime System”, Technical Remailbox . CMU/SEI-89-TR-15. ESD-TR-89-23. Software Engineering Institute Carnegie Mellon University, 1989.
[7] Sha, L., Lehoczky, J.P., and Rajkumar, R. “Priority Inheritance Protocols: An Approach to Real-Time Synchronization”. Tech. Rept. CMU-CS-87-181, Carnegie Mellon University, Computer Science Department, 1987.
[8] Krzysztof M. Sacha, “Measuring the Real-Time Operating System Performance”, Institute of Control and Computation Engineering, Warsaw University of Technology, Poland, 1995.




How to Cite

Pessolani, P. A. (2008). MINIX4RT: Real-time Semaphores. Journal of Computer Science and Technology, 8(03), p. 139–143. Retrieved from



Original Articles