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Chapter1 Introduction to Computers

Chapter1 Introduction to Computers. What are computers?. 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.

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Chapter1 Introduction to Computers

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  1. Chapter1Introduction to Computers

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

  3. Look inside the computer SOFTWARE HARDWARE

  4. Computers are made of • HARDWARE • SOFTWARE

  5. Hardware غير مطلوبة فقط للفهم

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

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

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

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

  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. 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. 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

  14. Hardware Organization CPU memory hard drive غير مطلوبة فقط للفهم

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

  16. Hardware Organization CPU memory motherboard hard drive غير مطلوبة فقط للفهم

  17. 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)

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

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

  20. 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.

  21. 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.)

  22. Hardware Organization CPU memory motherboard hard drive غير مطلوبة فقط للفهم

  23. 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

  24. 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.

  25. Main Memory Address Memory locations 1 2 3 n Memory Cell

  26. Main Memory

  27. 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 )

  28. 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 “ …… ” ?

  29. 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

  30. Kinds of Disk Drives

  31. 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

  32. 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

  33. Common Secondary Media Hard drive

  34. Hardware Organization CPU memory motherboard hard drive غير مطلوبة فقط للفهم

  35. Common Secondary Media 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 thandiskettes DVD: Digital Video Disk

  36. Common Secondary Media

  37. 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

  38. 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.

  39. 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.

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

  41. CPU Output Devices • Pieces of equipment that translate the processed informationfrom the CPUinto a form that humans can understand. Processed information

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

  43. Software • The instructionsthattellthecomputerwhat to do • Application Software - helps end-users perform general purpose tasks • System Software - enables application software to interact with the computer

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

  45. 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, …

  46. 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).

  47. Examples ofMicrocomputer Operating System Software • DOS - original standard for IBM compatibles • Windows - a graphical operating environment • Windows VISTA, XP, millennium, 2000, 98, and 95 Continue …

  48. Examples ofMicrocomputer 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 ?

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

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