Network Operating Systems Partha Dasgupta Department of Computer Science and Engineering Arizona State University Tempe AZ 85287-5406 USA
[email protected] [Note: Written in 1997, Appeared in Encyclopedia of Electrical Engineering] 1. Introduction Network Operating Systems extend the facilities and services provided by computer operating systems to support a set of computers, connected by a network. The environment managed by a network operating system consists of an interconnected group of machines that are loosely connected. By loosely connected, we mean that such computers possess no hardware connections at the CPU – memory bus level, but are connected by external interfaces that run under the control of software. Each computer in this group run an autonomous operating system, yet cooperate with each other to allow a variety of facilities including file sharing, data sharing, peripheral sharing, remote execution and cooperative computation. Network operating systems are autonomous operating systems that support such cooperation. The group of machines comprising the management domain of the network operating system is called a distributed system. A close cousin of the network operating system is the distributed operating system. A distributed operating system is an extension of the network operating system that supports even higher levels of cooperation and integration of the machines on the network (features include task migration, dynamic resource location, and so on) (1,2). An operating system is low-level software controlling the inner workings of a machine. Typical functions performed by an operating system include managing the CPU among many concurrently executing tasks, managing memory allocation to the tasks, handling of input and output and controlling all the peripherals.