8.)Define the essential properties of the following types of OS:

ANSWER:
a. Batch-In a computer, a batch job is a program that is assigned to the computer to run without further user interaction. Examples of batch jobs in a PC are a printing request or an analysis of a Web site log. In larger commercial computers or servers, batch jobs are usually initiated by a system user. Some are defined to run automatically at a certain time.

In some computer systems, batch jobs are said to run in the background and interactive programs run in the foreground. In general, interactive programs are given priority over batch programs, which run during the time intervals when the interactive programs are waiting for user requests.

The term originated with mainframe computers when punched cards were the usual form of computer input and you put a batch of cards (one batch per program) in a box in the sequence that they were to be fed into the computer by the computer operator.

b.Time Sharing-Refers to the concurrent use of a computer by more than one user -- users share the computer's time. Time sharing is synonymous with multi-user. Almost all mainframes and minicomputers are time-sharing systems, but most personal computers and workstations are not.

c.Real Time-Occurring immediately. The term is used to describe a number of different computer features. For example, real-time operating systems are systems that respond to input immediately. They are used for such tasks as navigation, in which the computer must react to a steady flow of new information without interruption. Most general-purpose operating systems are not real-time because they can take a few seconds, or even minutes, to react.

Real time can also refer to events simulated by a computer at the same speed that they would occur in real life. In graphics animation, for example, a real-time program would display objects moving across the screen at the same speed that they would actually move.

d.Network- In information technology, a network is a series of points or nodes interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks.

The most common topology or general configurations of networks include the bus, star, Token Ring, and mesh topologies. Networks can also be characterized in terms of spatial distance as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs).

A given network can also be characterized by the type of data transmission technology in use on it (for example, a TCP/IP or Systems Network Architecture network); by whether it carries voice, data, or both kinds of signals; by who can use the network (public or private); by the usual nature of its connections (dial-up or switched, dedicated or nonswitched, or virtual connections); and by the types of physical links (for example, optical fiber, coaxial cable, and Unshielded Twisted Pair). Large telephone networks and networks using their infrastructure (such as the Internet) have sharing and exchange arrangements with other companies so that larger networks are created.

network Last modified: Monday, November 13, 2006

(n.) A group of two or more computer systems linked together. There are many types of computer networks, including: local-area networks (LANs) : The computers are geographically close together (that is, in the same building). wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves. campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base. metropolitan-area networks MANs): A data network designed for a town or city. home-area networks (HANs): A network contained within a user's home that connects a person's digital devices. In addition to these types, the following characteristics are also used to categorize different types of networks: topology : The geometric arrangement of a computer system. Common topologies include a bus, star, and ring. See the Network topology diagrams in the Quick Reference section of Webopedia. protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network . architecture : Networks can be broadly classified as using either a peer-to-peer or client/server architecture.