Priority Semaphores

Strengthen, Widen, Get Semaphores

Many parallel programs are expressed in terms of conditional atomic actions with different degrees of atomicity. It is known that these synchronization primitives are expensive to implement in its fully generality [2]. Many platforms provide an efficient set of synchronization primitives. Semaphores are a very special case of conditional atomic actions which can be considered a canonical synchr...

Monitors and Semaphores

Process Scheduling and UNIX Semaphores

Semaphores have been used extensively in programming concurrent tasks. Various extensions have been proposed for problems in which traditional semaphores turned out to be difficult to use. The extended semaphore primitives investigated here are based on the version of semaphores implemented in UNIX System V. Implementation issues are discussed and practical illustrations of their use are provid...

Solutions Based on Binary Semaphores

A graphical form of the mutual exclusion problem is considered in which each vertex represents a process and each edge represents a mutual exclusion constraint between the critical sections of the processes associated with its endpoints. An edge semaphore solution for mutual exclusion problems is defined, and those graphs which are edge solvable are characterized in terms of both a forbidden su...

Proving Properties of Real-Time Semaphores

Much work has been undertaken on investigating the use of semaphore primitives in concurrent programming languages. It has been shown that semaphores are adequate for expressing many forms of concurrency control, including the enforcement of communication protocols, and mutual exclusion protocols on shared resources. In this paper we present a formal language for real-time distributed programs ...