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1 Chapter1 Introduction to Computers. 2 Computers are electronic devices that can follow instructions to accept input, process the input and then produce.

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Presentation on theme: "1 Chapter1 Introduction to Computers. 2 Computers are electronic devices that can follow instructions to accept input, process the input and then produce."— Presentation transcript:

1 1 Chapter1 Introduction to Computers

2 2 Computers are electronic devices that can follow instructions to accept input, process the input and then produce information. It is a machine that manipulates data according to a set of instructions. What are computers?

3 3 HARDWARE SOFTWARE Look inside the computer

4 4 Computers are made of 1.HARDWARE 2.SOFTWARE

5 5 Hardware غير مطلوبة فقط للفهم

6 6 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

7 7 The Case (System Unit or System Cabinet) غير مطلوبة فقط للفهم

8 8 Hardware 1.Central Processing Unit (CPU) 2.Input units 3.Output units 4.Memory (Main or Primary Memory & Secondary or Auxiliary Memory)

9 9 Components of a Computer System Central Processing Unit ( CPU ) control unit (CU) Arithmetic logic Unit (ALU) RAM ROM Memory Input units output units Auxiliary Memory Data Information /Knowledge

10 10 Hardware Organization motherboard CPU memory hard drive Input Devices... غير مطلوبة فقط للفهم

11 11 Input Devices Translate data from form that humans understand to one that the computer can work with Most common are keyboard and mouse Selector Buttons

12 12 Examples of Input Devices 1. Keyboard ( QWERTY keyboard, ATMs keyboard ) ATM: automatic teller machine 2. Mouse 3. Scanner 4. Pre-storage Devise 5. Optical mark recognition (Light Pin, Bar code scanners) 6. Microphone 7. Joystick.

13 13 8. Point and Draw devices 9. Trackball 10. Touchpad 11. Touch screen 12. Magnetic stripes and smart cars. 13. Digital Cameras Examples of Input Devices(2)

14 14

15 15 Hardware Organization CPU memory hard drive غير مطلوبة فقط للفهم

16 16 RAM Mother-Board (or Main Board) CPU ROM غير مطلوبة فقط للفهم

17 17 Hardware Organization motherboard CPU memory hard drive غير مطلوبة فقط للفهم

18 18 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)

19 19 The CPU consists of : Control Unit (CU) Arithmetic and Logical Unit (ALU) Some Registers

20 20 Central Processing Unit (CPU) Control Unit (CU) Arithmetic Logic Unit (ALU) This is CPU Only: Registers Central Processing Unit (CPU)

21 21 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.

22 22 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.)

23 23 Hardware Organization motherboard CPU memory hard drive غير مطلوبة فقط للفهم

24 24 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

25 25 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.

26 26 Main Memory AddressMemory locations 123n123n Memory Cell

27 27 Main Memory

28 28 ROM: Read Only Memory ROM is part of memory n Programmed at manufacturing time n Its contents cannot be changed by users n It is a permanent store Q: Mention some examples of ROM? A: (PROM & EPROM )

29 29 Other Kind of Memory nPROM: Programmable Read Only Memory. nEPROM: Erasable Programmable Read Only Memory nCache Memory nRegisters: not part of the main memory. Q : Registers are part of …… ?

30 30 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

31 31 Drives Kinds of Disk Drives

32 32 Common Secondary Media DiskettesDiskettes –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

33 33 Common Secondary Media Hard drive –Data is represented magnetically as with diskettes platter –Normally more than one rigid platter in a sealed unit disksnot removable –These disks are not removable –Significantly more capacity and faster operating than diskettes

34 34 Hard drive Common Secondary Media

35 35 Hardware Organization motherboard CPU memory hard drive غير مطلوبة فقط للفهم

36 36 Optical Laser Discs CD ROM & DVDs 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 Common Secondary Media DVD: Digital Video Disk

37 37 Approximate printed 8.5 x 11 inch pages Amount of storageDisk size 180 pages360 Kb5.25 low density 360 pages720 Kb3.5 low density 600 pages1.2 Mb5.25 high density 720 pages1.44 Mb3.5 high density a small library700 MBCD a feature length movie8.5 GBDVD Common Secondary Media

38 38 tapes 3.5 inch diskettesPanasonic's LS inch diskettes Iomega's Zip & Jazz disks VCR tape (Video Cassette Recorder ) Flash USB disks MMC (Multi Media Card ) SD Common Secondary Media

39 39 The benefits of secondary storage can be summarized as follows: Capacity. Organizations may store the equivalent of a roomful of data on sets of disks that take up less space Reliability. Data in secondary storage is basically safe, since secondary storage is physically reliable.

40 40 Convenience. With the help of a computer, authorized people can locate and access data quickly. Cost. It is less expensive to store data on tape or disk (the principal means of secondary storage) than to buy and house filing cabinets.

41 41 Hardware Organization CPU memory hard drive Output … غير مطلوبة فقط للفهم

42 42 Output Devices frominto Pieces of equipment that translate the processed information from the CPU into a form that humans can understand. CPU Processed information

43 43 Output Devices Monitors Printers Dot matrix printers Ink jet printers Laser printers Sound Blasters (Sound Card By Creative Lab) Controlling other devices

44 44 Software 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

45 45 System Software The most important System Software is the Operating System Examples of operating systems: Windows XP, DOS, Apple, UNIX

46 46 System Software The software that controls everything that happens in a computer. Background software, manages the computers internal resources Resources examples : CPU, RAM, I/O devices, …

47 47 All hardware and software are under the control of the operating system All hardware and software are under the control of the operating system. 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).

48 48 Examples of 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 …

49 49 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 Question: List some examples of operating systems ? Examples of Cont. Examples of Microcomputer Operating System Software Cont.

50 50 Application Software Packaged - off the shelf, pre-written programs ( General purpose) Custom - written for an organizations specific purpose (Special purpose) PackagedCustom

51 51 Application Software – Basic Tools example: Microsoft wordWord processors– example: Microsoft word example: Microsoft ExcelSpreadsheets-- example: Microsoft Excel example: Microsoft AccessDatabase managers-- example: Microsoft Access PhotoshopGraphics-- example: Photoshop Spreadsheets: Computer software that allows the user to enter columns and rows of numbers in a accounting book like format.

52 52 Units of Measurements Bit (Binary Digit)(takes two values: 1 or 0) Byte = 8 bits KB (Kilo-byte) = 1024 bytes MB (mega-byte) = 1024 KB GB (giga-byte) = 1024 MB TB (Tera-byte) = 1024 GB Remark: 1024=2 10

53 53 1.Microcomputers Four Kinds of Computers 3. Mainframe computers 2. Minicomputers 4. Supercomputers

54 54 Comparison Comparison between the previous kinds of computers may made based on : Price Processing Speed Storage Capacity Powerful Single-user or Multi-user Supporting hundreds (or thousands) of users simultaneously Computer Size Companies size …etc.

55 55 Microcomputer =>Personal Computer => PC There are 3 types of the Microcomputers : 1.Laptop 2.Desktop 3.Workstation

56 56 Personal Computer: A small, single-user computer based on a microprocessor. Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has : a more powerful microprocessor and, in general, a higher-quality monitor.

57 57 Minicomputer, Mainframe, and Supercomputer hundreds simultaneouslyMinicomputer: A multi-user computer capable of supporting up to hundreds of users simultaneously. hundredsor thousandssimultaneouslyMainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. extremely fast computerSupercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second.

58 58 Small enough for a desktop, but not easily portable Personal computers (PCs) run general purpose software and are employed by a wide spectrum of users Desktop Computer

59 59 WorkstationsWorkstations are powerful machines, running more advanced software, for technical, scientific, or data- intensive tasks These distinctions, however, are blurring Desktop Computers Cont.

60 60 Easily transported from one place to another Portable Computers

61 61 Portable Computers Four categories 1.Laptops 2.Notebooks 3.Sub-notebooks 4.Personal Digital Assistants (PDA) Q: list all portable computer categories?

62 62 PDA

63 63

64 64 Desk-sized More processing speed and storage capacity than microcomputers General data processing needs at small companies Larger companies use them for specific purposes Minicomputers

65 65 غير مطلوبة OMITTED

66 66 Larger machines with special wiring and environmental controls Faster processing and greater storage than minicomputers Typical machine in large organizations Mainframe Computers

67 67 غير مطلوبة OMITTED

68 68 The most powerful of the four categories Used by very large organizations, particularly for very math-intensive types of tasks Supercomputers

69 69 Supercomputers

70 70 1- Store a large amount of data and information for a long period of time. 2- process data and information in high accuracy level. 3- Speed in processing data information. 4- Sharing of information / network. Characteristics of Computers

71 71 Understanding Understanding the difference between Data, Information and Knowledge: Computer Data Knowledge Information

72 72 Data Data: is the name given to basic facts such as names and numbers. Information Information: is data that has been converted into a more useful or intelligible form. Knowledge Knowledge: arrangement of information and classifying information of the same type or the same topic.

73 73 Data: are details of various types of transactions and details relating to specific situations, which are input to a data processing system (e.g. computer) for processing in a prescribed way. Examples of data relating to students are student-number, student-name and grades. Data

74 74 e. g. data information (data) | | sort \ / (information)

75 75 Data Document files Worksheet files Database files

76 76 Information Information: the result of processing data. n Information: Must serve a useful purpose Must be of an acceptable level of accuracy Must be available at the right time Must be relevant to the enterprise, person, … etc.

77 77 Knowledge Putting a number of information with the same type or same topic would be a knowledge.

78 78 Processing data produces information, and processing information produces knowledge.

79 79 Computer Viruses

80 80 Computer Viruses A computer virus are small software programs that are designed to spread from one computer to another and to interfere with computer operation. A virus might corrupt or delete data on your computer, use your program to spread itself to other computers, or even erase everything on your hard disk.

81 81 Examples of Viruses Win32/Conficker INF/Autorun Win32/PSW.OnLineGames n32/Agent

82 82 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 help Anti-virus programs can help

83 83 Types of Computer Viruses Macro Viruses A macro virus, often scripted into common application programs such as Word or Excel, is spread by infecting documents. Network Viruses rapidly spreads through a Local Network Area (LAN), and sometimes throughout the internet. Trojan Horses The Trojan virus once on your computer, doesn't reproduce, but instead makes your computer susceptible to malicious intruders by allowing them to access and read your files. Making this type of virus extremely dangerous to your computer's security and your personal privacy.

84 84 Types of Computer Viruses Logic Bombs a piece of code that are inputted into a software system. When a certain and specific condition is met, such as clicking on an internet browser or opening a particular file, the logic bomb virus is set off. Companion Viruses takes advantage of MS-DOS. This virus creates a new file with typically the.COM extensions, but sometimes the.EXD extension as well.

85 85 Types of Computer Viruses Boot Sector Viruses generally hide in the boot sector, either in the bootable disk or the hard drive. Unlike most viruses, this virus does not harm the files in the hard disk, but harm the hard disk itself. Multipartite Viruses spreaded through infected media and usually hides in the memory. Gradually, the virus moves to the boot sector of the hard drive and infects executable files on the hard drive and later across the computer system.

86 86 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

87 87 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

88 88 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.

89 89 Some tips that will help minimize your vulnerability to viruses: 1.Delete s from unknown or suspicious, untrustworthy (unreliable) sources, especially those with files attached to an . 2.Never open a file attached to an 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.


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