Tuesday, August 11, 2009

Get Started with Basic information !

You must have basic knowledge and information regarding the terms used in this vast field of computer science. I have given such information below regarding such a terms, protocols and other general information. If you have any queries, doubts or any arguments regarding it, you are most welcome!

What is Computer ?

A programmable machine. The two principal characteristics of a computer are:

  • It responds to a specific set of instructions in a well-defined manner.
  • It can execute a prerecorded list of instructions (a program).

Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

All general-purpose computers require the following hardware components:

  • memory: Enables a computer to store, at least temporarily, data and programs.
  • mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
  • input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.
  • output device : A display screen, printer, or other device that lets you see what the computer has accomplished.
  • central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.
  • What is Server?

    A computer or device on a network that manages network resources. For example, a file server is a computer and storage device dedicated to storing files. Any user on the network can store files on the server. A print server is a computer that manages one or more printers, and a network server is a computer that manages network traffic. A database server is a computer system that processes database queries.

    What is Client ?

    A client does not share any of its resources, but requests a server's content or service function. Clients therefore initiate communication sessions with servers which await (listen to) incoming requests. A client is the requesting program or user in a client/server relationship. For example, the user of a Web browser is effectively making client requests for pages from servers all over the Web. The browser itself is a client in its relationship with the computer that is getting and returning the requested HTML file.

    What is Client-Server Relation ?

    Client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request. Although the client/server idea can be used by programs within a single computer, it is a more important idea in a network. In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations. Computer transactions using the client/server model are very common. For example, to check your bank account from your computer, a client program in your computer forwards your request to a server program at the bank. That program may in turn forward the request to its own client program that sends a request to a database server at another bank computer to retrieve your account balance. The balance is returned back to the bank data client, which in turn serves it back to the client in your personal computer, which displays the information for you.

    What is Network and Networking ?

    In the world of computers,
    networking is the practice of linking two or more computing devices together for the purpose of sharing data. A network is simply a collection of computers or other hardware devices that are connected together, either physically or logically, using special hardware and software, to allow them to exchange information and cooperate. Networking is the term that describes the processes involved in designing, implementing, upgrading, managing and otherwise working with networks and network technologies.

    What are types Of Networking ?

    Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans.
    Local area networks (LANs), for example, typically reach across a single home, whereas wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.

    LAN - Local Area Network

    A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

    WAN - Wide Area Network

    As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.

    A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

    A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

    Other Types of Area Networks

    While LAN and WAN are by far the most popular network types mentioned, you may also commonly see references to these others:
    • Wireless Local Area Network - a LAN based on WiFi wireless network technology
    • Metropolitan Area Network - a network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation.
    • Campus Area Network - a network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.
    • Storage Area Network - connects servers to data storage devices through a technology like Fiber Channel.
    • System Area Network - links high-performance computers with high-speed connections in a cluster configuration. Also known as Cluster Area Network.

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