Distributed Computing

         
             First you'll think what is distributed computing? you might have heard of distributed systems where a collection of independent computers that appears to its users as a single coherent system. where many machines are working together to fulfill users requirement but user feels that he is working on a single machine. so what is distributed computing then?   Distributed computing is a science which solves a large problem by giving small parts of the problem to manycomputers to solve and then combining the solutions for theparts into a solution for the problem, In a distributed computing setup, the program runs like itwould in a single computer even when it is, in fact, usingdifferent computer processors.


why to use distributed computing?

• A computer that is part of a distributed computing network usually has a program installed in it that is its direct link to the administrative server or servers.
• The software remains dormant in the individual computer until such time that the computer's system becomes idle .
• At this point, the software will be activated and will inform the administrative server about available resources in the computer.
• The administrative server will respond by sending an application package to the requesting computer.
• The moment the user has need of his own resources again,the management server will immediately relinquish the resources that it has been monopolizing, back to the owner of the computer.

what are the challenges you will face in distributed computing?

1. Heterogeneity

            Various Systems in the Distributed must be able to communicatewith each other despite of different:

• Hardware
• Programming Language
• Operating Systems
• Network

    2.   Scalability

          The system should work efficiently with increase in number of users.

     

    3.   Security

• Security in Distributed system consists of two Components:Confidentiality: Protection against unauthorized users.Integrity: Protection against alteration.
• Encryption techniques can be used.

  4.   Transparency

        

         The Entire System Should appear as a Single Unit and theInteractions between the Components should be typicallyhidden from the Users.

Applications:

• Telephone Network.
• Computer network such as the Internet.
• aircraft control systems.
• Banking system

Disadvantages of distributed computing:

• A lot of extra programming is required to set up a distributed system.
• If not planned properly, a distributed system can decrease the overall reliability of computers.
• A node could get a work unit, and then not complete it, which would affect remaining nodes.