Computer Network

Computer Network

        Computer Network is the combination of two or more computers connected through a communication system that allows exchange of information between computers.A computer network means interconnection collection of autonomous computers.The connection can be made using copper wire, lasers, micro waves or by using communication satellites.The old model of a single computer serving all of the organisational computational needs  
is replaced by one in which a large number of separate but interconnected computers do the job.


       Network can range in scope from a single location to almost global.Networks also usually involve telecommunication between PC's and are very important in office information systems.


Advantages of Networks


    A network can be useful for those frequent situation in which computer users wish to share information, secondary storage, peripheral devices or a database.For example a user may wish to send another user information in the form of a document , a graph or a spread sheet analysis.Without a network, the usual way to do this is to physically share a floppy disc.This cubersome  and the disc can become damaged and unreadable.Using a network the user can simply send the information over the network to the other user without having to store on a floppy disc.
      To say in a more general way the issue here is Resource sharing and the aim is to make all the programs, data and peripherals available to anyone on the network, without regard to the physical location of the resource and the user.This means that even if a user is several kilometer away from the data, it should not prevent him from using the data.
      All files can have copies on one or two computers, even if one of them is not available due to some hardware error, the pther copy can be used .This is called Reliability.In addition, the presence of multiple CPU means that even if one goes down the other may be able to take over the work with reduced performance.This is very important for banking, air traffic control and military applications.
     Small computers have a better price/performance ratio than large ones.A mainframe computers can be 10 times faster than a PC but it costs a thousand times than a PC.Therefore system designers build systems consisting of one PC per user, with data kept on one or more shared file servers.This saves money.
     Another advantage is that it is a powerful Communication medium.A network makes it easy for two or more people who lived apart to write a report together.When one person makes changes to an on-line document the other can view the changes immediately.This helps for co-operation among geographically spread groups of people.
    Networks are Scalable i.e, the system performance can be increased gradually as the work load grows by adding more processors.