Introduction To Computer System جبمعة أم القرى قسم السنة التحضيريه اعداد: أعضبء هيئة التدريس Computer Generations First Second Third Fourth Computer Generations The First Transistor (1948) IBM 360 Computer System IBM 704 Used discrete transistors IBM 709 Mainframe Last of the vacuum tube computers, c. 1959 Digital Equipment Corp Left: DEC PDP-8, c. 1965 Right: DEC PDP-11, c. 1970 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: Computer Classifications (types) Microcomputer Minicomputer Mainframe Supercomputer Microcomputer Users: One Speed: Slow Price: $500 - $3,000 Size: desktop or smaller Examples: IBM PC, Apple ][, Apple Macintosh, Imac “personal computers” Minicomputer 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”) Supercomputer Users: a few Speed: very, very fast Price: $ millions Size: room Examples: Cray, Fujitsu scientific uses 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. Look inside the computer SOFTWARE HARDWARE 16 Computers are made of 1. HARDWARE 2. SOFTWARE 17 Hardware 18 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 19 The Case (System Unit or System Cabinet) 20 Hardware 1. Central Processing Unit (CPU) 2. Input units 3. Output units 4. Memory (Main or Primary Memory & Secondary or Auxiliary Memory) 21 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 Memory /Knowledge 22 Hardware Organization Input Devices ... CPU memory motherboard hard drive 23 Input Devices • Translate data from form that humans understand to one that the computer can work with • Most common are keyboard and mouse 24 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 . 25 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 26 27 Hardware Organization CPU memory hard drive 28 غير مطلوبة فقط للفهم )Mother-Board (or Main Board غير مطلوبة فقط للفهم غير مطلوبة فقط للفهم CPU RAM ROM 92 Hardware Organization CPU memory motherboard hard drive غير مطلوبة فقط للفهم 30 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) 31 The CPU consists of : Control Unit (CU) Arithmetic and Logical Unit (ALU) Some Registers 32 Central Processing Unit (CPU) Central Processing Unit (CPU) Control Unit (CU) Arithmetic Logic Unit (ALU) Registers 33 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. 34 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.) 35 Hardware Organization CPU memory motherboard hard drive 36 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 37 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. Main Memory 39 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. 40 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 ) 41 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 “ …… ” ? 42 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 43 Kinds of Disk Drives 44 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 45 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 46 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 47 Digital Video Disk DVD: 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 48 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 49 Hardware Organization CPU memory hard drive 50 غير مطلوبة فقط للفهم Output … CPU Output Devices Pieces of equipment that translate the processed information from the CPU into a form that humans can understand. 51 Output Devices Monitors Printers Dot matrix printers Ink jet printers Laser printers Sound Blasters (Sound Card By Creative Lab) Controlling other devices 52 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 53 System Software The most important System Software is the Operating System Examples of operating systems: Windows XP, DOS, Apple, UNIX 54 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, … 55 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). 56 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 57 Continue … 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 58 systems ? Application Software Packaged Custom • Packaged - “off the shelf”, pre-written programs ( General purpose) • Custom - written for an organization’s specific purpose (Special purpose) 59 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 60 columns and rows of numbers in a accounting book like format. Internet 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 fails Network Network Internet Internet Internet 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 ARPANET 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 numbers) 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 http://www.uqu.edu.sa/cs100/windows.htm specifies the protocol as http, the host or WWW server as uqu.edu.jo and the document as /cs100/windows.htm Internet Corporation for Assigned Names and Numbers (ICANN) 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 – 220.127.116.11 – 10.15.3.20 (Intranet, Local IP) To find your IP number on Windows – Execute ipconfig on your command prompt – XP 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 Browsers 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 another 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 e-mail. 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.