Intoduction by fanzhongqing


									‫‪Introduction To Computer System‬‬

                                  ‫جامعة أم القرى‬
                           ‫قسم السنة التحضيريه‬
                      ‫اعداد: أعضاء هيئة التدريس‬
Computer Generations

   First
   Second
   Third
   Fourth
Computer Generations

                       First        Second       Third       Fourth

 Years           1951-1958     1959-1964     1965-1970    1971-

 Technology      Vacuum        Transistor    Integrated   Large Scale
                 Tubes                       Circuits     Integrated
 I/O             Cards         Tape          Disks        Variety

 Size            Room          Closet        Desk         Small

 $ per million   $10           $1            $0.10        $0.0001 or
The First Transistor (1948)
IBM 360 Computer System
IBM 704
IBM 709 Mainframe

                    Last of the
                      c. 1959
Digital Equipment Corp

           Left: DEC PDP-8, c.

           Right: DEC PDP-11,
                       c. 1970

What is the Computer ?
    The Computer is a set of independent physical components and devices
    (Hardware), which have a specific job to do for each one and working together
    by Software to make up the computer system.

Computer perform three main operations:
Computer Classifications (types)

   Microcomputer
   Minicomputer
   Mainframe
   Supercomputer

   Users:        One
   Speed:        Slow
   Price:        $500 - $3,000
   Size:         desktop or smaller
   Examples:     IBM PC, Apple ][, Apple
                  Macintosh, Imac
   “personal computers”

   Users:         2 - 50
   Speed:         Faster
   Price:         $10,000 - $250,000
   Size:          file cabinet
   Examples:      HP 9000
                   DEC VAX
   “departmental computers”
Mainframe Computer

   Users:        50 +
   Speed:        Fast
   Price:        $500,000 - millions
   Size:         refrigerator-sized on up
   Examples:     IBM 3090, Unisys 2200

   company-wide (“enterprise”)

   Users:            a few
   Speed:            very, very fast
   Price:            $ millions
   Size:             room
   Examples:         Cray, Fujitsu

   scientific uses
     Look inside the computer



          Computers are made of

     1.   HARDWARE
     2.   SOFTWARE



     The parts of computer itself (tangible objects )
         including :
           CPU (or Processor) and Primary memory (or
            Main Memory)
           Input devices i.e the keyboard and mouse
           Output devices
           Storage devices

     The Case (System Unit or System Cabinet)


     1.   Central Processing Unit (CPU)
     2.   Input units
     3.   Output units
     4.   Memory (Main or Primary Memory &
          Secondary or Auxiliary Memory)

Components of a Computer System
        Central Processing Unit (CPU)
         control unit (CU)

                                  Memory           output
         logic                     RAM              units
         Unit (ALU)
units                                    ROM

                             Auxiliary         Information
                              Memory           /Knowledge
               Hardware Organization
Input Devices ...




                                    hard drive
              Input Devices

     • Translate data from form that humans
       understand to one that the computer can
       work with
     • Most common are keyboard and mouse

         Examples of Input Devices

     1. Keyboard
     2. Mouse
     3. Scanner
     4. Pre-storage Devise (Disk, CD’s, … etc.)
     5. Optical mark recognition (Light Pin , Bar
       code scanners)
     6. Microphone
     7. Joystick .

     Examples of Input Devices(2)

     8. Point and Draw devices
     9. Trackball
     10. Touchpad
     11. Touch screen
     12. Magnetic stripes and smart cars.
     13. Digital Cameras

     Hardware Organization



                              hard drive

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 ‫)‪Mother-Board (or Main Board‬‬
     ‫غير مطلوبة فقط للفهم‬

                                  ‫غير مطلوبة فقط للفهم‬




     Hardware Organization




                                   hard drive
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       Central Processing Unit (CPU)

     • A specific chip or the processor
       a CPU's performance is determined by
       the rest of the computers circuitry and
     • The Central Processing Unit (CPU)
       performs the actual processing of data
     • The speed (clock speed) of CPU
       measured by Hertz (MHz)

     The CPU consists of :

        Control Unit (CU)
        Arithmetic and Logical Unit (ALU)
        Some Registers

     Central Processing Unit (CPU)

       Central Processing Unit (CPU)

               Control Unit (CU)

               Arithmetic Logic
               Unit (ALU)


     The Control Unit (CU) :

         coordinates all activities of the
         computer by:

        Determining which operations to perform and
         in what order to carry them out.
        The CU transmits coordinating control signals to
         other computer components.
     The ALU :

     consists of electronic circuitry to

        Arithmetic operations (addition, subtraction,
         multiplication and division)
        Logical operations (and, or, not, …) and to
         make some comparisons (less-than, equal, …
     Hardware Organization




                            hard drive
35               ‫غير مطلوبة فقط للفهم‬
     Primary Memory

        Memory (fast, expensive, short-term
         memory): Enables a computer to store, at
         least temporarily, data, programs, and
         intermediate results.

        Two general parts:
         1.   RAM
         2.   ROM
     Main Memory

     RAM (Main Memory)

        its a primary storage or random access memory (RAM).
        it temporarily holds data and programs for use during
         processing (volatile)
        Any information stored in RAM is lost when the computer
         is turned off.
        RAM is the memory that the computer uses to
         temporarily store the information as it is being
         processed. The more information being processed the
         more RAM the computer needs.
        RAM consists of locations or cells. Each cell has a
         unique address which distinguishes it from other cells.
           ROM: Read Only Memory

     ROM is part of memory
        Programmed at manufacturing time
        Its contents cannot be changed by users
        It is a permanent store

     Q: Mention some examples of ROM?
     A: (PROM & EPROM )

             Other Kind of Memory

        PROM: Programmable Read Only Memory.
        EPROM: Erasable Programmable Read Only
        Cache Memory
        Registers: not part of the main memory.

     Q : Registers are part of “ …… ” ?

               Secondary Storage

      Stores data and programs permanently:
      its retained after the power is turned off
      Examples
       • Hard Drive (Hard Disk)
          Located outside the CPU, but most often
          contained in the system cabinet
       • Floppy Disk
       • Optical Laser Discs
           CD-ROM, CD-RW, and DVD
     Kinds of Disk Drives

       Common Secondary Media

• Diskettes
  – Data represented as magnetic spots on removable
    flexible plastic disks
  – Most common size is 3 1/2 inches, in a rigid plastic
  – Disk drive holds the diskette, reads or retrieves
    the data and writes or stores data

       Common Secondary Media

     • Hard drive
       – Data is represented magnetically as with
       – Normally more than one rigid platter in a
         sealed unit
       – These disks are not removable
       – Significantly more capacity and faster
         operating than diskettes
      Optical Laser Discs

      CD ROM & DVD’s
              Data is represented as pits and lands
              Some kinds are read only (CD-ROM) and some Kinds are
               rewritable (CD-RW)
              Significantly more capacity and faster operating than

45 Digital Video Disk
    Common Secondary Media

                                        Approximate printed
   Disk size        Amount of storage
                                        8.5 x 11 inch pages

5.25 low density         360 Kb               180 pages
3.5 low density          720 Kb              360 pages
5.25 high density        1.2 Mb               600 pages
3.5 high density        1.44 Mb              720 pages
      CD                700 MB             a small library
     DVD                 8.5 GB         a feature length movie

          Common Secondary Media

        tapes
        Panasonic's LS120 3.5 inch diskettes
        Iomega's Zip & Jazz disks
        VCR tape (Video Cassette Recorder )
        Flash USB disks
        MMC (Multi Media Card )
        SD

                Hardware Organization



                                      hard drive

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     Output …

               Output Devices

       Pieces of equipment that translate the
       processed information from the CPU into a
       form that humans can understand.

                  Output Devices

      Monitors
      Printers
        Dot matrix printers
        Ink jet printers
        Laser printers

      Sound  Blasters (Sound Card By Creative Lab)
      Controlling other devices

        The instructions that tell the computer
        what to do
     1. Application Software - helps end-users
        perform general purpose tasks
     2. System Software - enables application
        software to interact with the computer

           System Software

     The most important

     System Software
     is the

     Operating System

     Examples of operating systems:
     Windows XP, DOS, Apple, UNIX

                    System Software

     • The software that controls everything
       that happens in a computer.
     • Background software, manages the
       computer’s internal resources

      Resources examples : CPU, RAM , I/O devices, …
     All hardware and software are under the control of
     the operating system.
     Among other things, the operating system:
     1.   Determines how valuable RAM is allotted to programs.
     2.   Performs tasks related to file management.
     3.   Sets priorities for handling tasks.
     4.   Manages the flow of instructions, data and information
          to and from the processor (CPU).

        Examples of Microcomputer
        Operating System Software

     • DOS - original standard for IBM
     • Windows - a graphical operating
         Windows VISTA, XP, millennium,
         2000, 98, and 95

55     Continue …
     Examples of Microcomputer
     Operating System Software Cont.
     • Windows NT - for powerful workstations &
     • OS/2 - competitor to Windows 2000
     • Macintosh Operating System
     • Unix - originally for minicomputers, now used
       on microcomputers and Internet servers

     Question: List some examples of operating
56    systems ?
          Application Software

            Packaged       Custom
     • Packaged - “off the shelf”, pre-written
               programs ( General purpose)
     • Custom - written for an organization’s
          specific purpose (Special purpose)

     Application Software – Basic Tools

     • Word processors– example: Microsoft
     • Spreadsheets-- example: Microsoft
     • Database managers-- example:
       Microsoft Access
     • Graphics-- example: Photoshop
     Spreadsheets: Computer software that allows the user to enter
58    columns and rows of numbers in a accounting book like format.
Talk Flow!

   Introduction to the Internet
    –   Brief history
    –   Explaining basic protocols
    –   Naming on the net
   HTML
   Using search engines
   Questions
     What is the Internet?

   A Network of Computer Networks
    –   Started as early as the 1960s
    –   Built to work even if a large part of the network



               World Wide Web?

   A part of the Internet
    –   www1, www2 etc.,
   Based on hypertext and hypertext transfer
    protocol (HTML & HTTP)
   Supports multiple media - Multimedia
   Interactive, dynamic HTML
Brief History of the Internet

   1960s - Department of Defense initiative
   1973 - ARPA launches the Internetting Project
    to explore the possibilities of linking networks
   1980 – First Virus halts the Internet
   1984 – DNS Introduced (Names rather than
   1999 – Internet Banking
          Services through the net

   Major services:
    –   Email – Electronic Mail
    –   FTP – File Transfer Protocol
    –   Gopher (TCP/IP)
    –   Newsgroups
    –   Telnet – Remote session
    –   WAIS – Wide Area Information System
    –   WWW – World Wide Web
         How to read an URL

specifies the protocol as http,
the host or WWW server as
and the document as /cs100/windows.htm
          Getting a Domain Name?

   Top Domains:
     – edu – Educational Institutions
     – com – Company / Commercial Organizations
     – org – Non-profit Organizations
     – net – Network, network of sites
     – mil – Military Installations
     – gov – Government sites

   Sub Domains:
     – sa- Saudi Arabia
     – jo - Jordan
     – uk – United Kingdom
Identifying a PC on the Internet

   IP Number
    – (Intranet, Local IP)

   To find your IP number on Windows
    –   Execute ipconfig on your command prompt – XP

   Hypertext, a method of preparing text that
    allows readers to choose their own pathways
    through the material, is invented by Ted
   The underlined word represents a hyperlink
    that lets the reader click and jump to a new
   Provides interactive browsing

   Browser software allows us to view, hear,
    retrieve information created for the web

   Internet Explorer, Netscape Navigator, Lynx
Computer Viruses
    Computer Viruses

–   A computer virus is an application program designed and
    written to destroy other programs.

–   It has the ability to:
       Link itself to other programs
       Copy itself (it looks as if it repeats itself)
Examples of Viruses

   Monkes
   ABC
   Crabs
   CIH
Viruses and Virus Protection

   A virus program
    –   Infects programs, documents,
        databases and more …
    –   It is man-made
    –   It can hide and reproduce
    –   It can lay dormant (inactive) and
        then activate

        Anti-virus programs can help
Viruses and Virus Protection (2)

   A variety of highly contagious “viruses” can spread from
    computer to computer, much the way biological viruses do
    among human beings.
      Just as a virus can infect human organs, a computer
       virus can infect programs and databases. It can also
       hide duplicates of itself within legitimate programs.
    Viruses and Virus Protection(3)
      These viruses, which are programs, reside on and are passed
       between magnetic disks.
      Most people who write and circulate virus programs fall into
       two groups.
     1.   The first group uses viruses to show off for their peers.
     2.   The second, and far more dangerous group, creates
          viruses with malicious intent.
Sources of Computer Viruses

             Three primary sources
              –   The Internet
                      Via downloads and exchanges
              –   Diskettes
                      Exchanging disks
              –   Computer networks
                      Can spread from one network to
How do you know if you have a virus?

   Lack of storage capability
   Decrease in the speed of executing programs
   Unexpected error messages
   Halting the system
   Virus Protection

• The software package distributed with new PCs always
  includes an antiviral program. The best way to cope
  with viruses is to recognize their existence and use an
  antiviral, or antivirus program.
     Some tips that will help minimize your
            vulnerability to viruses:

1.   Delete e-mails from unknown or suspicious, untrustworthy
     (unreliable) sources, especially those with files attached to an
2.   Never open a file attached to an e-mail unless you know what
     it is, even if it appears to come from a friend.
3.   Download files from the Internet only from legitimate and
     reputable sources.
4.   Update your antivirus software at least every two weeks as
     over 200 viruses are discovered each month.
5.   Backup your files periodically
6.   Traditionally virus protection has been at the PC or client level.
     However, this may change as companies look to network and
     Internet service providers for more services.
Computer Ethics

   You shall not use a computer to harm other people.
   You shall not snoop around in other people's computer files.
   You shall not use a computer to steal.
   You shall not use other people's computer resources without
    authorization or proper compensation.
    You shall always use a computer in ways that show
    consideration and respect for your fellow humans.
Computer Uses
1- Supermarkets: Use a bar code reader.
2- Libraries: Use computers to search for books; to record books
lending and return ….
3- Banks: Enable customers to access their accounts via ATM.
4- Plastic Cards: Used in computer system to facilitate customers
life (mobile, telephone and credit cards)
5- Electronic Commerce: Uses Internet in business for
purchasing, payment, or reservations.
6- Touch Screens: Allow unskilled customers to access
information easily.
7- Hospitals: Use computers to store records of patients and to
help in the diagnosis and analysis of the treatment.
8- Cars: Computers are used to display maps and give
instructions to the driver.

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