Scheduling and Synchronization in Real Time Systems

Real time computing is a wide open research area of intellectually challenging computer science problems with direct payoos to current technology. Real time systems have brought in huge challenges in a wide range of computer science disciplines, and each of those challenges must be met before the science of large scale real time systems can become a reality. This paper provides an overview of several issues related to scheduling and synchronization of real time systems, the two major challenging areas of research for real time systems. Every real time systems designer must be aware of the the issues related to real time system design, feasibility and complexity of their solutions,a set of classical scheduling theory results that rarely provide direct solutions but do provide insight in choosing a good system design and scheduling algorithm, the set of basic synchronization protocols that has been designed to deal with the problems created by the direct application of commonly used synchronization primitives like semaphores and monitors, the programming abstractions provided by the languages to cater to the speciications of the real time syatems, the increasing complexity of all the above mentioned issues for a multiprocessing real time system. All these have been addressed in the following sections and an eeort has been made so that the reader can develop an overall critical view about the issues related to scheduling and synchronization in real time system.In SectionI I present the basic concepts of real time systems followed by Section II which presents several problems related to scheduling and synchronization in real time systems and approaches towards their solution. In Section III and Section IV the scheduling algorithms and the synchronization protocls that has been devised for such sytems are discussed in details. Section V presents concluding remarks.