Distributed Systems
Abstract
This chapter demystifies computing systems consisting of multiple CPUs, shared and distributed memory, and different types of I/O in the form of multiprocessors and multicomputers that eventually gave rise to distributed computing systems and parallel architecture. The generic multiprocessor operating systems with numerous considerations used in different forms of multiprocessor architecture with emphasis on processor management are described, along with a brief presentation of Linux OS and Windows OS in multiprocessor systems. The design issues of the generic multicomputer operating systems that drive the different models of multicomputer system architecture are described. The design issues of the basic distributed operating system (DOS) are explained. DOS, when run on networks of computers, gives rise to a true distributed system, which has been briefly described. Networks of computers run by network operating systems (NOSs) give rise to computer networks, which are properly addressed. Brief design issues of one form of DOS with all its components run on a client/server model with interprocess communication realized either by the message-passing technique or remote procedure call (RPC) using procedure call/return syntax and semantics are described. Implementation of SUN RPC is presented here as a case study. The distributed file system, a major part of distributed systems, realized in Windows, SUN NFS, and Linux GPFS, is presented here as an implementation example. The most modern approach in distributed computer system design, which is a base substitute of a true costly distributed system known as cluster, is built up essentially on the platform of a computer network system comprising heterogeneous, complete, stand–alone, and autonomous machines (computers) operated by loosely coupled NOS supported by an additional aid of a software layer known as middleware. The advantages of clusters, their classifications, and different methods of clustering, along with the general architecture of clusters and operating system issues, are explained. The different aspects of implementation of Windows and SUN clusters are presented here as examples of practical implementation.