Survey of Contemporary Real Time System
Informatica 29 (2005) 233–240 233
A Survey of Contemporary Real-time Operating Systems
S. Baskiyar, Ph.D. and N. Meghanathan
Dept. of Computer Science and Software Engineering
Auburn University
Auburn, AL 36849, USA baskiyar@eng.auburn.edu http://www.eng.auburn.edu/~baskiyar
Keywords: scheduling, POSIX, kernels.
Received: June 26, 2004
A real-time operating system (RTOS) supports applications that must meet deadlines in addition to providing logically correct results. This paper reviews pre-requisites for an RTOS to be POSIX 1003.1b compliant and discusses memory management and scheduling in RTOS. We survey the prominent commercial and research RTOSs and outline steps in system implementation with an RTOS. We select a popular commercial RTOS within each category of real-time application and discuss its real-time features. A comparison of the commercial RTOSs is also presented. We conclude by discussing the results of the survey and suggest future research directions in the field of RTOS.
Povzetek: Podan je pregled operacijskih sistemov v realnem času.
1
Introduction
A real-time system is one whose correctness involves both the logical correctness of outputs and their timeliness [7]. It must satisfy response-time constraints or risk severe consequences including failure. Real-time systems are classified as hard, firm or soft systems. In hard real-time systems, failure to meet response-time constraints leads to system failure. Firm real-time systems have hard deadlines, but where a certain low probability of missing a deadline can be tolerated.
Systems in which performance is degraded but not destroyed by failure to meet response time constraints are called soft real-time systems.
An embedded system is a specialized real-time computer system that is part of a larger system. In the past, it was designed for specialized applications, but reconfigurable and programmable embedded systems are becoming popular.
Some examples of
A Survey of Contemporary Real-time Operating Systems
S. Baskiyar, Ph.D. and N. Meghanathan
Dept. of Computer Science and Software Engineering
Auburn University
Auburn, AL 36849, USA baskiyar@eng.auburn.edu http://www.eng.auburn.edu/~baskiyar
Keywords: scheduling, POSIX, kernels.
Received: June 26, 2004
A real-time operating system (RTOS) supports applications that must meet deadlines in addition to providing logically correct results. This paper reviews pre-requisites for an RTOS to be POSIX 1003.1b compliant and discusses memory management and scheduling in RTOS. We survey the prominent commercial and research RTOSs and outline steps in system implementation with an RTOS. We select a popular commercial RTOS within each category of real-time application and discuss its real-time features. A comparison of the commercial RTOSs is also presented. We conclude by discussing the results of the survey and suggest future research directions in the field of RTOS.
Povzetek: Podan je pregled operacijskih sistemov v realnem času.
1
Introduction
A real-time system is one whose correctness involves both the logical correctness of outputs and their timeliness [7]. It must satisfy response-time constraints or risk severe consequences including failure. Real-time systems are classified as hard, firm or soft systems. In hard real-time systems, failure to meet response-time constraints leads to system failure. Firm real-time systems have hard deadlines, but where a certain low probability of missing a deadline can be tolerated.
Systems in which performance is degraded but not destroyed by failure to meet response time constraints are called soft real-time systems.
An embedded system is a specialized real-time computer system that is part of a larger system. In the past, it was designed for specialized applications, but reconfigurable and programmable embedded systems are becoming popular.
Some examples of
References: [1] S.R. Ball, Embedded Microprocessor Systems: Real World Design, Third edition, Newnes, 2002. no. 9, 1984. [3] H.Gomaa, Software Design Methods for Concurrent and Real-time Systems, First edition, AddisonWesley, 1993. [4] S.Heath, Embedded Systems Design, Second edition, Newnes, 2002. [6] System Application Program Interface, ANSI/IEEE Std 1003.1, 1996 Edition http://www.esmertec.com, Accessed Nov 15, 2004. IEEE Press, 1997. 46-61, 1973. [9] J.W.S. Liu, Real-time Systems, First edition, Prentice Hall, 2000. http://www.lynuxworks.com, Accessed Nov 15, 2004 http://www.microsoft.com, Accessed Nov 10, 2004 A SURVEY OF CONTEMPORARY... Informatica 29 (2005) 233–240 239 Synchronization