Your personal computer hardware Your personal computer by pengxuebo

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									Your personal computer hardware                                                  Your personal computer hardware

  Input: What Goes In
  Input:                                                                                             Memory:
                                                                                   The processor and Memory: Data manipulation
  Input is the data that you put into the computer system for processing.          The processor which is also called the Central Processing Unit (CPU)
  Common ways of feeding input data into the system:                                   executes the program instructions and communicate with the
  –   Typing on a keyboard                                                             input, output and storage devices.
  –   Pointing with a mouse                                                        –                                               information.
                                                                                       The processor actually transforms data into information
  –   Scanning with a wand reader, bar code reader, flatbed scanner                –   Data is the raw material, e.g. grades in a class
          Wand and bar reader use laser beams to read special letters, numbers     –   Processed data becomes information – data that is organised,
          or symbols, such as the black and white bar codes found on many              meaningful and useful, e.g. class average.
          Flatbed scanners are used to scan pictures or printed documents into
          your computer

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Your personal computer hardware                                                  Networking

  Computer memory is also known as the primary storage is closely                  A network is a system that uses communication devices to connect

      related to CPU but separate and distinct from it.                                computers and their resources. The resources include printers,

  –   Memory holds data after it is input into the system and before it is             hard disks, and even software and data.

      processed                                                                    Local Area Network (LAN) is one type of network.

  –   Memory holds the data after it has been processed but before it              –   e.g. personal computers in an office are connected together so

      has been released to the output device                                           that users can communicate with one another.

  –   Memory holds the programs needed by the CPU.                                 –   Users   can   operate    their   computers   independently   or   in

  –   Memory can hold data only temporarily because memory requires                    cooperation with other computers to exchange data and share

      a continuous flow of electric current; if the current is interrupted             resources.

      the data is lost.

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Networking                                                                             The Internet

  Individual users in homes or offices can connect to other computers,                   The Internet, sometimes called simply “the Net.” is the largest network system
      e.g. via a telephone line. Connecting computers via phone line                         of them all, connecting users worldwide.

      requires the use of a hardware device called modem. The modem
                                                   modem.                                –   The Internet is not really a single network but a loosely organised collection
                                                                                             of thousands of networks
      is used to reconcile the inherent differences between computer
                                                                                         –   No one owns the Internet
      and phone systems.
                                                                                         Getting Connected
          An important service provided is e-mail which lets people send and receive
                                                                                         –   How are all kinds of different computers able to communicate with one
          messages via computer
                                                                                         –   To access the Internet a computer must connect to a type of computer
                                                                                             called server. Each server uses the same special software called TCP/IP
                                                                                         –   TCP/IP stands for Transmission Control Protocol/Internet Protocol.
                                                                                         –   TCP/IP is the standard that allows         different types of computers to
                                                                                             communicate with each other.
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The Internet                                                                           Classification of Computers

  –   The supplier of the server computer often called an Internet                       Computers come in sizes from tiny to monstrous in both appearance
      Service Provider(ISP).                                                                 and power. The size of the computer needed depends on the
                                                                                             person or organisation computing requirements.
  Getting Around
  –   The most common method used to move around the Internet is                         o   Personal Computers
      called browsing .                                                                  o   Notebook Computers
  –   Using a program called browser you can use the mouse to point                      o   Smaller still: Handheld Computers.
      and click on the screen text or pictures to explore the Internet,                  o   Midrange Computers
      particularly the World Wide Web (WWW or Web)                                       o   Mainframes
  –   Each different location on the web is called a Web site                            o   Supercomputers
  –   The main page of a website is called home page

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Classification of Computers                                               Classification of Computers

  Personal Computers (PCs)                                                  Notebook Computers
  –                                       microcomputers.
      Desktop computers are also known as microcomputers Personal           –   Notebook computers are lightweight (often under six pounds) and
      computers categories:                                                     portable.
          Low-end functional computers (cheap PCs)                          –   The memory and storage of a notebook today compete with those
          Fully powered PCs                                                     of desktop computers
          Upper-end PCs called workstations used by specialised             –   Notebooks can run most available software
          people such as engineers, graphic designers.                      –   However, they carry a price tag greater than that of a full-size PC
  –   Workstations are small enough to fit a desktop but approach the           with the same features.
      power of a mainframe

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Classification of Computers                                               Classification of Computers

  Smaller still: Handheld Computers                                         Midrange Computers
  –                              (PDA),
      Personal Digital Assistant (PDA) also called pen-based computers,
      is a handheld computer. It can be used to keep track of               –   Midrange computers are multi-user computers designed to serve
      appointments and other business information.                              the needs of medium-sized organizations.
  –   Many PDAs offer multiple functions including wireless email and       –   Hundreds or even thousands of users can be connected to a
      fax capabilities.                                                         midrange computer via terminals or networked PCs to access
  –   Pocket PC is a handheld computer with slightly more power than a          company-wide applications.

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Classification of Computers                                                    Classification of Computers

  Mainframes                                                                     Supercomputers
  –   Mainframes are large computers that are capable of processing              –   The mightiest computers, and the most expensive.
      data at a very high speeds—billions of instructions per second–            –   Supercomputers are also the fastest, they can process trillions of
      and have access to trillions of characters of data.                            instructions per second
  –   The price of these systems can vary from several hundred                   –   Supercomputers can be used for mainstream activities, such as:
                                                                                        Stock analysis
      thousands to many millions of dollars.
                                                                                        Automobile design
  –   Their principal use is for processing vast amount of data quickly                 Special effects for movies

                                                                                 –   For many years customers of supercomputers were an exclusive
                                                                                     group: agencies of federal government, for tasks that require
                                                                                     massive data manipulation, such as world-wide weather forecast.

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