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Introduction To Computer System

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1 Introduction To Computer System
جامعة أم القرى قسم السنة التحضيريه اعداد: أعضاء هيئة التدريس

2 Computer Generations First Second Third Fourth FIRST GENERATION
- vacuum tubes used - slow I/O, punched cards - problems with heat and maintenance - used for payroll and record keeping - Univac I SECOND GENERATION - used transistors (developed at Bell Labs) - used tape for I/O - increased speed and reliability (threw off less heat) - used for billing and inventory - IBM 4101, Honeywell 200 THIRD GENERATION - used integrated circuits - used magnetic disks for I/O - airline reservations and market forecasting - IBM 360, NCR 395

3 Computer Generations FOURTH GENERATION
- used large-scale integrated circuits - increased storage capacity and speed - greater variety of I/O devices - tape, disk, microfilm, voice - used for simulation, CAD/CAM - IBM 3090, Sperry Univac 1100 FIFTH GENERATION - ??? - gallium arsenide instead of silicon? - true artificial intelligence? - bio-engineered computers?

4 The First Transistor (1948)

5 IBM 360 Computer System

6 Used discrete transistors
IBM 704 Used discrete transistors

7 IBM 709 Mainframe Last of the vacuum tube computers, c. 1959

8 Digital Equipment Corp
Left: DEC PDP-8, c. 1965 Right: DEC PDP-11, c. 1970

9 Computer 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:

10 Computer Classifications (types)
Microcomputer Minicomputer Mainframe Supercomputer The four generally accepted classifications of computer size. Note that these are approximate, and not hard and fast - probably can find examples to disprove what I am saying!

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

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

13 Mainframe Computer Users: 50 + Speed: Fast Price: $500,000 - millions
Size: refrigerator-sized on up Examples: IBM 3090, Unisys 2200 company-wide (“enterprise”)

14 Supercomputer Users: a few Speed: very, very fast Price: $ millions
Size: room Examples: Cray, Fujitsu scientific uses

15 Understand the Terms Intelligent and Dumb Terminal.
An intelligent terminal, for example a PC: - Performs a lot of the processing locally You could use a PC, linked to a mainframe A dumb terminal: - Has very limited processing capabilities itself, but allows you to connect to a large powerful computer such as a mainframe. When you process your data from the dumb terminal, it is the mainframe at the other end of the network that is performing all the calculations.

16 Look inside the computer

17 Computers are made of HARDWARE SOFTWARE

18 Hardware

19 Hardware 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

20 The Case (System Unit or System Cabinet)

21 Hardware Central Processing Unit (CPU) Input units Output units
Memory (Main or Primary Memory & Secondary or Auxiliary Memory)

22 Components of a Computer System
Central Processing Unit (CPU) Data control unit (CU) Memory Arithmetic logic Unit (ALU) output units RAM Input units ROM Auxiliary Memory Information/Knowledge

23 Hardware Organization
Input Devices ... CPU memory motherboard hard drive

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

25 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 .

26 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


28 Hardware Organization
CPU memory hard drive غير مطلوبة فقط للفهم

29 Mother-Board (or Main Board)
غير مطلوبة فقط للفهم غير مطلوبة فقط للفهم CPU RAM ROM

30 Hardware Organization
CPU memory motherboard hard drive غير مطلوبة فقط للفهم

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

32 The CPU consists of : Control Unit (CU)
Arithmetic and Logical Unit (ALU) Some Registers

33 Central Processing Unit (CPU)
Control Unit (CU) Arithmetic Logic Unit (ALU) Registers

34 coordinates all activities of the computer by:
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.

35 consists of electronic circuitry to perform:
The ALU : consists of electronic circuitry to perform: Arithmetic operations (addition, subtraction, multiplication and division) Logical operations (and, or, not, …) and to make some comparisons (less-than, equal, … etc.)

36 Hardware Organization
CPU memory motherboard hard drive غير مطلوبة فقط للفهم

37 Primary Memory Memory (fast, expensive, short-term memory): Enables a computer to store, at least temporarily, data, programs, and intermediate results. Two general parts: RAM ROM

38 Know How Computer Memory Is Measured
Bit All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit. Byte A byte consists of eight bits. Kilobyte A kilobyte (KB) consists of 1024 bytes. Megabyte A megabyte (MB) consists of 1024 kilobytes. Gigabyte A gigabyte (GB) consists of 1024 megabytes.

39 Main Memory

40 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.

41 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 )

42 Other Kind of Memory PROM: Programmable Read Only Memory.
EPROM: Erasable Programmable Read Only Memory Cache Memory Registers: not part of the main memory. Q : Registers are part of “ …… ” ?

43 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

44 Kinds of Disk Drives

45 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 case Disk drive holds the diskette, reads or retrieves the data and writes or stores data

46 Common Secondary Media
Hard drive Data is represented magnetically as with diskettes Normally more than one rigid platter in a sealed unit These disks are not removable Significantly more capacity and faster operating than diskettes

47 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 diskettes DVD: Digital Video Disk

48 Approximate printed 8.5 x 11 inch pages
Common Secondary Media Approximate printed 8.5 x 11 inch pages Amount of storage Disk size 180 pages 360 Kb 5.25 low density 360 pages 720 Kb 3.5 low density 600 pages 1.2 Mb 5.25 high density 720 pages 1.44 Mb 3.5 high density a small library 700 MB CD a feature length movie 8.5 GB DVD

49 Common Secondary Media
tapes Panasonic's LS inch diskettes Iomega's Zip & Jazz disks VCR tape (Video Cassette Recorder ) Flash USB disks MMC (Multi Media Card ) SD

50 Hardware Organization
CPU memory hard drive غير مطلوبة فقط للفهم Output …

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

52 Output Devices Monitors Printers
Dot matrix printers Ink jet printers Laser printers Sound Blasters (Sound Card By Creative Lab) Controlling other devices

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

54 System Software System Software Operating System The most important
is the Operating System Examples of operating systems: Windows XP, DOS, Apple, UNIX

55 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, …

56 Among other things, the operating system:
All hardware and software are under the control of the operating system. Among other things, the operating system: Determines how valuable RAM is allotted to programs. Performs tasks related to file management. Sets priorities for handling tasks. Manages the flow of instructions, data and information to and from the processor (CPU).

57 Examples of Microcomputer Operating System Software
DOS - original standard for IBM compatibles Windows - a graphical operating environment Windows VISTA, XP, millennium, 2000, 98, and 95 Continue …

58 Examples of Microcomputer Operating System Software Cont.
Windows NT - for powerful workstations & networks 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 systems ?

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

60 Application Software – Basic Tools
Word processors– example: Microsoft word Spreadsheets-- example: Microsoft Excel Database managers-- example: Microsoft Access Graphics-- example: Photoshop Spreadsheets: Computer software that allows the user to enter columns and rows of numbers in a accounting book like format.

61 Internet

62 Talk Flow! Introduction to the Internet HTML Using search engines
Brief history Explaining basic protocols Naming on the net HTML Using search engines Questions

63 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 fails

64 Network Network Internet Internet Internet
OSPF (Open Shortest Path First) or IS-IS (Intermediate System-to-Intermediate System). Internet Internet

65 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

66 Brief History of the Internet
1960s - Department of Defense initiative ARPANET ARPA launches the Internetting Project to explore the possibilities of linking networks 1980 – First Virus halts the Internet 1984 – DNS Introduced (Names rather than numbers) 1999 – Internet Banking

67 Services through the net
Major services: – Electronic Mail FTP – File Transfer Protocol Gopher (TCP/IP) Newsgroups Telnet – Remote session WAIS – Wide Area Information System WWW – World Wide Web

68 How to read an URL specifies the protocol as http, the host or WWW server as and the document as /cs100/windows.htm

69 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 .biz .info

70 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            

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

72 Browsers Browser software allows us to view, hear, retrieve information created for the web Internet Explorer, Netscape Navigator, Lynx

73 Computer Viruses

74 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)

75 Examples of Viruses Monkes ABC Crabs CIH

76 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

77 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.

78 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. The first group uses viruses to show off for their peers. The second, and far more dangerous group, creates viruses with malicious intent.

79 Sources of Computer Viruses
Three primary sources The Internet Via downloads and exchanges Diskettes Exchanging disks Computer networks Can spread from one network to another

80 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

81 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.

82 Some tips that will help minimize your vulnerability to viruses:
Delete s from unknown or suspicious, untrustworthy (unreliable) sources, especially those with files attached to an . Never open a file attached to an unless you know what it is, even if it appears to come from a friend. Download files from the Internet only from legitimate and reputable sources. Update your antivirus software at least every two weeks as over 200 viruses are discovered each month. Backup your files periodically 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.

83 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.

84 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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