Introduction to Computers PDF

Chapter1 Introduction to Computers 1  What are computers? Computers are electronic devices that can follow instructions to accept input, process the input and then produce information. 2  Look inside the computer SOFTWARE HARDWARE...

Chapter1 Introduction to Computers 1  What are computers? Computers are electronic devices that can follow instructions to accept input, process the input and then produce information. 2  Look inside the computer SOFTWARE HARDWARE 3  Computers are made of 1. HARDWARE 2. SOFTWARE 4  Hardware 5 The Case (System Unit or System Cabinet) 6  Computer Systems System Unit Output device Output device Output device Input device Input device  Hardware 1. Central Processing Unit (CPU) 2. Input units 3. Output units 4. Memory (Main or Primary Memory & Secondary or Auxiliary Memory) 8 Components of a Computer System Central Processing Unit (CPU) Data control unit (CU) Memory output Arithmetic logic RAM units Input Unit (ALU) units ROM Auxiliary Information 9 Memory /Knowledge  Hardware Organization Input Devices... CPU memory motherboard hard drive 10  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 11  Examples of Input Devices 1. Keyboard (QWERTY keyboard, ATMs keyboard) ATM: automatic teller machine 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. 12 Parts of a Computer Input Devices  Mouse  Keyboard  Microphone  Scanner  Webcam 14  Hardware Organization CPU memory hard drive 15 16  The CPU consists of :  Control Unit (CU)  Arithmetic and Logical Unit (ALU)  Some Registers 17  Hardware Organization CPU memory motherboard hard drive 18  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 19  Memory Computer Memory - millions/billions of on/off charges Divided into:  Bits0 or 1  Bytes Groups of 8 bits A byte is the smallest unit of storage. (Can hold one text character)  Words Groups of bits/bytes (8, 16, 32, 64-bits)  Memory Storage is usually too large to be expressed in bytes or words. Instead we use:  Kilobyte (KB) = 1024 bytes (210 bytes)  Megabyte (MB) = 1024 x 1024 bytes or one million bytes (220 bytes)  Gigabyte (GB) = 1024 x 1024 x 1024 bytes or one trillion bytes (230 bytes)  Terabyte (TB) = 1024 x 1024 x 1024 x 1024 bytes one quadrillion bytes (240 bytes)  Memory By number of bytes available for storage  Size Approximate AbbreviationTerm 1 thousand bytes KB or KKilobyte 1 million bytes MBMegabyte 1 billion bytes GBGigabyte 1 trillion bytes TBTerabyte  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. 23  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 24  DIFFERENCES BETWEEN RAM AND ROM RAM ROM Data and Stores during Stored by program and after manufacturer processing Content Stores Stores instructions information (Information) temporarily permanently Processing Very fast, but Fast, but uses very time uses a lot little power of power Volatility Volatile Non-volatile  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 26 CD-ROM, CD-RW, and DVD  Kinds of Disk Drives 27  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 than diskettes 28  Hardware Organization CPU memory hard drive 29 Output … CPU Output Devices Pieces of equipment that translate the processed information from the CPU into a form that humans can understand. 30 Parts of a Computer Output Devices  Monitor  Printer  Speaker/Headphone  Output Devices  Monitors  Printers  Dot matrix printers  Ink jet printers  Laser printers  Sound Blasters (Sound Card By Creative Lab)  Controlling other devices 32  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 33  Application Software – Basic Tools Word processors– example: Microsoft word Spreadsheets-- example: Microsoft Excel Database managers-- example: Microsoft Access Graphics-- example: Photoshop 34  Four Kinds of Computers 1. Microcomputers 2. Minicomputers 3. Mainframe computers 4. Supercomputers 35   Microcomputer =>Personal Computer => PC  There are 3 types of the Microcomputers : 1.Laptop 2.Desktop 3.Workstation 36  Characteristics of Computers 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. 37   Data: is the name given to basic facts such as names and numbers.  Information: is data that has been converted into a more useful or intelligible form.  Knowledge: arrangement of information and classifying information of the same type or the same topic. 38   e. g. -2 4 0 -3 10 (data) || sort \ / -3 -2 0 4 10 (information) 39  Processing data produces information, and processing information produces knowledge. 40  Computer Viruses 41  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) 42