"信号量集"在并发进程同步问题中的应用研究

本文在阐述进程同步与互斥、信号量以及P、V操作等基本概念的基础上,探讨了利用P、V操作结合信号量机制实现操作系统中进程控制的一般方法,得到了用于构造同步算法的基本框架;最后对一般信号量集机制中的特殊情况在"五兄弟圈羊"问题中的应用作了具体描述.     

信号量在生产者-消费者及其变形问题中的应用

生产者-消费者问题是操作系统中进程同步互斥的经典问题,在其之上的变形问题在实际应用中非常广泛,用信号量机制描述此类问题,并给出相应的解决方法。     

基于信号量机制实现特定数量关系下的进程同步

进程的同步与互斥是进程管理的重要内容,本文主要讨论了使用信号量机制实现一类具有特定数量关系要求的进程同步与互斥的方法。     

操作系统中进程同步实现方法探讨

进程同步是操作系统课程教学中的一个重点和难点,从区分简单的同步与互斥问题入手,归纳出单一的和混合的进程同步与互斥问题,并给出了解题思路和解题步骤。     

基于操作系统中进程同步的实现方法

用PV操作解决进程同步问题时首先应确定问题是属于进程互斥还是进程同步,或是互斥与同步的混合问题,然后根据共享资源的数量以及使用共享资源的规则正确的定义信号量及其初值,合理运用PV操作防止进程死锁,给出分析进程同步与互斥的方法来编制程序。     

Linux中信号量机制研究

在Linux中,信号量机制是实现并发进程同步、解决互斥的有效方法。文中以Linux2.4版为例,系统地研究了信号和信号量机制,从信号量分类入手详细论述了信号量的数据结构及相关调用,不仅为全面、清晰地研究信号与信号量机制提供了有益的参考,还为进一步应用信号量机制提供了支持。     

操作系统中进程同步的实现

进程同步包括进程的互斥和进程的同步两个方面,是操作系统管理共享资源的一种手段。对《操作系统》课程的进程同步教学问题进行了讨论,举例分析了通过P、V操作实现进程的同步与互斥的方法。     

Linux中信号量机制研究

在Linux中，信号量机制是实现并发进程同步、解决互斥的有效方法。文中以Linux2．4版为例，系统地研究了信号和信号量机制，从信号量分类入手详细论述了信号量的数据结构及相关调用，不仅为全面、清晰地研究信号与信号量机制提供了有益的参考，还为进一步应用信号量机制提供了支持。     

分时分区操作系统互斥信号量的设计与分析

随着航空电子系统日趋复杂化以及对安全性的不断提高,采用空间隔离、时间预先分配的分时分区操作系统已成为未来的发展方向。分时分区操作系统FCOS中为了使分区内部并发执行的多个任务之间合理有效的共享资源和相互合作,需要一种可靠的互斥信号量机制进行保障。文中设计了一种同时采用优先级继承和优先级天花板的混合型互斥信号量机制,并在PowerPC755平台与其他操作系统的互斥信号量进行了试验对比分析,证明其可以高效地防止任务间发生优先级反转。     

用信号量实现进程同步的一题四解方法

用信号量机制实现并发进程之间的同步是操作系统中研究的重要课题。对于该问题,进行了方法学的讨论,提出了四种解题方法,其中混合型方法实现了用最少的信号量实现进程同步的问题,对该知识点的理解和掌握很有帮助。     

深入浅出信号量机制

《操作系统》是高校计算机专业的一门非常重要的专业课程,理论性较强,尤其信号量机制一直是大家公认的学习操作系统的难点之一。学生不好懂,也不愿意学。该文从生活中常见的比较有意思的互斥同步的实例出发,介绍了使用信号量机制解决互斥和同步关系的方法。简单易懂,趣味性较强,寓教于乐,轻轻松松掌握抽象难懂的理论知识。     

Starvation-free mutual exclusion with semaphores

The standard implementation of mutual exclusion by means of a semaphore allows starvation of processes. Between 1979 and 1986, three algorithms were proposed that preclude starvation. These algorithms use a special kind of semaphore. We model this so-called buffered semaphore rigorously and provide mechanized proofs of the algorithms. We prove that the algorithms are three implementations of one abstract algorithm in which every competing process is overtaken not more than once by any other process. We also consider a so-called polite semaphore, which is weaker than the buffered one and is strong enough for one of the three algorithms. Refinement techniques are used to compare the algorithms and the semaphores.     

Synthesis of mutual exclusion 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 subgraph and a graph grammar. Finally, an efficient algorithm is given which generates the entry and exit sections for all processes in an edge-solvable problem     

How to solve the Santa Claus problem

John Trono (1994) published a new exercise in concurrent programming – the Santa Claus problem – and provided a solution based on semaphores. His solution is incorrect because it assumes that a process released from waiting on a semaphore will necessarily be scheduled for execution. We give a simple solution in Ada 95 using higher-order synchronization primitives: protected objects and rendezvous. We then give a solution in Java, although this solution is not as elegant as the Ada 95 solution because the Java synchronization primitives are rather limited. The problem demonstrates that semaphores, designed for low-level mutual exclusion, are not appropriate for solving difficult concurrent programming problems. © 1998 John Wiley & Sons, Ltd.     

一种多文件任务调度算法

计算机在处理多文件任务的时候,会出现同时读写文件的情况,文件将会出现数据读写不全或数据缺失.在Linux内核中,单处理器情况下,通过同步机制来进行任务的分配和处理,其中经典的有原子操作,信号量机制,互斥锁等实现方案.在多处理器系统中则是通过test-and-set原语操作来实现.本文通过设计一种多文件任务调度的算法,避免整个系统发生互斥访问.本文通过Matlab编程实现该算法,其结果表明本文提出的多文件调度算法能够有效的并行执行多文件任务.     

Extended semaphore operations

Extended semaphores systems such as in UNIX System V are a powerful extension of Dijkstra's semaphores. They allow efficient solutions to a number of classic synchronization problems. UNIX semaphore operations appear to be insufficiently well defined, in particular when a semaphore is repeated in an operator. This results in several solutions relying on assumed properties. A new semaphore operator, isem, based on extended semaphore operators is introduced. The operator isem is clearly defined, can be implemented efficiently, and yields simple solutions to many classic synchronization problems. Copyright © 2000 John Wiley & Sons, Ltd.     

本原性问题驱动模式在操作系统课堂教学中的应用

文章提出一个将本原性问题驱动教学模式引入操作系统课堂教学的改革方案。该方案的实施,力求超越对于技巧性问题的追求,深入到本原性、情景性问题所涉及到的实质,用反映操作系统本质的一系列问题来驱动课堂上的教与学活动,从而改变操作系统课程课堂教学缺乏互动、抽象无趣的现状,同时有利于培养学生的自学和创新能力。     

The STAB multiprocessing environment for CYBA-M

Multi-Thread STAB is an implementation of the notional STAB stack machine^1,2 on the CYBA-M multi-microprocessor.^3–5 Designed expressly for the study of synchronization and performance issues within multiprocessing, the MTS system comprises a highly interactive user interface and multiple program-gated clocks which, respectively, control and monitor the execution of a STAB kernel. This provides a flexible high-level environment within which multiple processor STAB programs may be run and analysed in terms of effective concurrency, sequential flow of control and interprocessor synchronization. The MTS kernel is a re-entrant STAB interpreter which can simultaneously support any number of 8080 processors, thereby implementing a notional STAB multiprocessor. The STAB processors communicate by access to common global data structures, and primitive binary semaphore operations are available to provide both simple and conditional mutual exclusion in critical regions. Any of the proposed schemes for controlled process interaction^6–10 may be implemented on the basis of these fundamental means for communication and synchronization. This provides a useful framework within which general high level multiprocessing control structures may be investigated, and also allows special structures to be created for optimized harnessing of concurrency in specific areas of applications research.     

基于信号量的Linux多线程同步研究

信号量是进程或线程之间相互通讯的手段之一。有效地使用可以在多线程之间实现同步和互斥，以保证程序的正确的运行。在对线程的数据结构和相关的10个函数分析的基础上，以一个具体的例子给出如何使用信号量机制实现多线程之间的同步。     

用VxWorks的信号量机制实现任务同步

为了保证诸任务对临界critical资源resource的互斥访问，VxWorks提供了任务同步机制。二进制信号量是VxWorks系统中实现任务同步的一种重要手段，它保证了任务在并发时结果的一致性。简要介绍二进制信号量，阐述用二进制信号量解决任务互斥和同步的方法，并给出二进制信号量应用在某数据采集系统中的程序框架。某数据采集系统中有效地利用了VxWorks的信号量机制，实现了8个接收通道的数据采集、数据存储以及数据查询等任务对缓冲区的共享。