Information technology


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Information technology

  1. 1. Chapter 6: Information Technology Hardware
  2. 2. Computer Hardware <ul><li>What is a computer system? </li></ul><ul><li>Number Systems and Character Representation </li></ul><ul><li>The CPU and primary storage </li></ul><ul><li>Secondary Storage </li></ul><ul><li>New Trends in Computer Hardware </li></ul>
  3. 3. What is a computer system? <ul><li>Central Processing Unit (CPU) </li></ul><ul><li>Primary storage </li></ul><ul><li>Input devices </li></ul><ul><li>Output devices </li></ul><ul><li>Communication devices </li></ul>
  4. 4. Components of Hardware CPU Primary Storage Secondary Storage Communications Devices Output Devices Input Devices Buses
  5. 5. Number Systems Humans represent numbers in Base10 1 x 10 3 = 1,000 9 x 10 2 = 900 9 x 10 1 = 90 7 x 10 0 = 7 Decimal Value: Numeric Expression: Digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 10 0 10 3 10 2 10 1 7 9 9 1
  6. 6. Computers use Base2 (0, 1) 1 0 1 1 1 0 1 Decimal Value: Numeric Expression: Base2: 1011101 = Base10: 1 x 2 6 0 x 2 5 1 x 2 4 1 x 2 3 1 x 2 2 0 x 2 1 1 x 2 0 64 0 16 8 4 0 1 = 93 2 0 2 6 2 5 2 4 2 3 2 2 2 1 64 32 16 8 4 2 1
  7. 7. Character representation ASCII: American Standard Code for Information Interchange (ASCII-8) Formula: 128 + 32 + Position in Alphabet 10100001: ‘A’ 10100010: ‘B’ 10100011: ‘C’ 10100100: ‘D’ 10100101: ‘E’ 01010000: ‘0’ 01010001: ‘1’ 01010010: ‘2’ 01010011: ‘3’ 01010111: __
  8. 8. Size of data storage <ul><li>Bit: 1 or 0 </li></ul><ul><li>Byte: 8 bits (equals 1 character) </li></ul><ul><li>Kilobyte: 1,000 bytes (exactly 1024) </li></ul><ul><li>Megabyte: 1,000,000 bytes </li></ul><ul><li>Gigabyte: 1,000,000,000 bytes </li></ul><ul><li>Terabyte: 1,000,000,000,000 bytes </li></ul>
  9. 9. Measurements of Time <ul><li>Millisecond: 1/1,000 second </li></ul><ul><li>Microsecond: 1/1,000,000 second </li></ul><ul><li>Nanosecond: 1/1,000,000,000 second </li></ul><ul><li>Picosecond: 1/1,000,000,000,000 second </li></ul>
  10. 10. <ul><li>Microprocessor: Very large-scale integrated circuit technology that integrates the computer's memory, logic, and control on a single chip. </li></ul><ul><li>Central Processing Unit (CPU) Area of the computer system that manipulates symbols, numbers, and letters, and controls the other parts of the computer system. </li></ul><ul><li>Primary Storage Part of the computer that temporarily stores program instructions and data being used by the instructions. </li></ul><ul><li>Arithmetic-logic Unit (ALU) Component of the CPU that performs the principal logic and arithmetic operations of the computer. </li></ul><ul><li>Control Unit Component of the CPU that controls and coordinates the other parts of the computer system. </li></ul>
  11. 11. Primary Storage <ul><li>RAM: Random Access Memory </li></ul><ul><li>ROM: Read Only Memory </li></ul><ul><li>PROM: Programmable ROM </li></ul><ul><li>Cache Memory </li></ul>
  12. 12. What is RAM? <ul><li>RAM: Random Access Memory </li></ul><ul><li>Primary Storage </li></ul><ul><li>No moving parts </li></ul><ul><li>Accessed at electronic speeds </li></ul><ul><li>Volatile (electrical interruption loses data) </li></ul>
  13. 13. Understanding RAM <ul><li>Programs and data are transferred to RAM from input devices or secondary storage </li></ul><ul><li>Nothing happens until data and program instructions are transferred from RAM to the CPU </li></ul><ul><li>Cache: a special kind of RAM, faster, more expensive, of smaller capacity </li></ul>
  14. 14. What is the difference between RAM and a floppy diskette? <ul><li>RAM is primary storage, floppies are secondary storage. </li></ul><ul><li>RAM is volatile, floppies are non-volatile. </li></ul><ul><li>RAM is online, floppies are stored off-line and placed online as needed. </li></ul><ul><li>RAM represents bits with electrical current, floppies represent bits with a magnetic field. </li></ul>
  15. 15. Control Unit <ul><li>Reads and interprets program instructions </li></ul><ul><li>Direct internal processor components </li></ul><ul><li>Moves programs and data in & out of RAM </li></ul><ul><li>Components </li></ul><ul><ul><li>Decoder: to decode instruction </li></ul></ul><ul><ul><li>Registers: to store instruction, data </li></ul></ul><ul><ul><li>Accumulator: to store results </li></ul></ul>
  16. 16. Arithmetic & Logic Unit <ul><li>Performs computations </li></ul><ul><li>Performs logic operations (>, <, =, AND, OR, XOR) </li></ul>
  17. 17. Machine Cycle <ul><li>Series of operations that are necessary to operate a single program instruction </li></ul><ul><li>Involves the following elements: </li></ul><ul><ul><li>Control Unit </li></ul></ul><ul><ul><li>ALU </li></ul></ul><ul><ul><li>Primary Storage </li></ul></ul>
  18. 18. Machine Cycle cont. 1. Fetch Instruction RAM to the Control Unit 2. Decode Instruction Control Unit 3. Execute Instruction ALU 4. Place Results in Memory ALU to RAM Instruction Time Execution Time
  19. 19. Processor Characteristics <ul><li>Word Size </li></ul><ul><li>Speed </li></ul><ul><ul><li>Micros: Megahertz (MHz) </li></ul></ul><ul><ul><li>Mainframes: MIPS </li></ul></ul><ul><ul><li>Supercomputers: FLOPS/GFLOPS </li></ul></ul><ul><li>RISC vs CISC architecture </li></ul><ul><li>Data Bus Width </li></ul>
  20. 20. Processor Terms <ul><li>RISC (reduced instruction set computing) Microprocessors that “have only the most frequently used instruction embedded in them” </li></ul><ul><li>MIPS: Millions of Instructions per second. MIPS are used to measure the speed of mainframes. </li></ul><ul><li>FLOPS: Floating point operations per second. A single floating point operation consists of multiple instructions (e.g. division). FLOPS are used to measure the speed of supercomputers. </li></ul>
  21. 21. Evolution of Computer Hardware <ul><li>Vacuum tube technology - 1946-56 </li></ul><ul><li>Transistors - 1957-63 </li></ul><ul><li>Integrated Circuits - 1964-79 </li></ul><ul><li>VLSI (Very Large Scale Integrated Circuits) - 1980-present </li></ul>
  22. 22. Popular Microprocessors <ul><li>Intel’s 80486, 100 MHz </li></ul><ul><li>Intel’s Pentium, 200+ MHz </li></ul><ul><li>Intel’s Pentium II, 333 MHz </li></ul><ul><li>Intel’s Pentium III, 700+ MHz </li></ul><ul><li>Motorola, IBM, Apple’s PowerPC, 450+ MHz </li></ul>
  23. 23. Classifying computers <ul><li>Personal Computer (PC) </li></ul><ul><ul><li>Small desktop or portable computer </li></ul></ul><ul><li>Workstation </li></ul><ul><ul><li>Desktop computer with powerful graphics and mathematical capabilities </li></ul></ul><ul><li>Server </li></ul><ul><ul><li>Computer designed to provide resources to other computers over a network </li></ul></ul><ul><li>Mainframe </li></ul><ul><ul><li>Used for high volume of business processing </li></ul></ul><ul><li>Supercomputer </li></ul><ul><ul><li>Designed to support complex computations </li></ul></ul>
  24. 24. Classifying computers continued <ul><li>Differences blurring due to increased processor speed and storage capacities. </li></ul><ul><li>Classes such as “minicomputers” are being eliminated. </li></ul><ul><li>I/O intensive applications served by mainframes. </li></ul><ul><li>Processing intensive applications served by supercomputers. </li></ul>
  25. 25. Secondary Storage <ul><li>Magnetic Tape </li></ul><ul><li>Magnetic Disks </li></ul><ul><ul><li>hard disks </li></ul></ul><ul><ul><li>floppy disks </li></ul></ul><ul><li>Optical Laser Disks </li></ul><ul><ul><li>Audio CDs </li></ul></ul><ul><ul><li>CD-ROMs </li></ul></ul><ul><ul><li>DVDs </li></ul></ul><ul><ul><li>W/R optical disks </li></ul></ul>
  26. 26. Sequential Processing Parallel Processing: Type of processing in which more than one instruction can be processed at a time by breaking down a problem into smaller parts and processing them simultaneously with multiple processors.
  27. 27. Client/Server Computing
  28. 28. Computer Networks and Client/Server Computing <ul><li>Distributed processing: The distribution of computer processing work among multiple computers linked by a communications network. </li></ul><ul><li>Centralized processing: Processing that is accomplished by one large central computer. </li></ul><ul><li>Client/server computing: A model for computing that splits processing between &quot;clients&quot; and &quot;servers&quot; on a network, assigning functions to the machine most able to perform the function. </li></ul><ul><li>Client: The user point-of-entry for the required function in client server computing. Normally a desktop computer, workstation, or laptop computer. </li></ul><ul><li>Downsizing: The process of transferring applications from large computers to smaller ones. </li></ul>
  29. 29. Network Computers <ul><li>Network computer (NC) Simplified desktop computer that does not store software programs or data permanently. Users download whatever software or data they need from a central computer over the Internet or an organization's own internal network. </li></ul><ul><li>Total cost of ownership (TCO) Designates the total cost of owning technology resources, including initial purchase costs, the cost of hardware and software upgrades, maintenance, technical support, and training. </li></ul>
  30. 30. Magnetic Tapes <ul><li>In the past, information systems used magnetic tapes for sequential processing. </li></ul><ul><li>Today, magnetic tapes are primarily used for: </li></ul><ul><ul><li>Backup of valuable files </li></ul></ul><ul><ul><li>Archiving files </li></ul></ul><ul><ul><li>File portability between computers </li></ul></ul>
  31. 31. Magnetic Disks <ul><li>Provide random/direct processing of files </li></ul><ul><li>Hard disks </li></ul><ul><li>Floppy disks: Removable magnetic disk storage primarily used with PCs. </li></ul><ul><ul><li>5 1/4 inch (1.2 MB) </li></ul></ul><ul><ul><li>3 1/2 inch (1.44 MB) </li></ul></ul><ul><li>Zip Drives </li></ul><ul><li>RAID (Redundant Array of Inexpensive Disks) Disk storage technology to boost disk performance by packaging more than 100 smaller disk drives with a controller chip and specialized software in a single large unit to deliver data over multiple paths simultaneously. </li></ul>
  32. 32. Magnetic Disks Tracks Sectors Read/Write Head Access Arm
  33. 33. Optical Disks <ul><li>Laser technology </li></ul><ul><li>Audio CDs </li></ul><ul><li>CD-ROM </li></ul><ul><li>DVDs </li></ul><ul><li>R/W CD ROMS </li></ul>
  34. 34. Input Devices <ul><li>Computer mouse: Handheld input device whose movement on the desktop controls the position of the cursor on the computer display screen. </li></ul><ul><li>Touch screen Input device technology that permits the entering or selecting of commands and data by touching the surface of a sensitized video display monitor with a finger or a pointer. </li></ul>
  35. 35. Input Devices <ul><li>Source data automation: Input technology that captures data in computer-readable form at the time and place the data are created. </li></ul><ul><li>Optical character recognition (OCR): Form of source data automation in which optical scanning devices read specially designed data off source documents and translate the data into digital form for the computer. </li></ul><ul><li>Bar code: Form of OCR technology widely used in supermarkets and retail stores in which identification data are coded into a series of bars. </li></ul><ul><li>Magnetic ink character recognition (MICR): Input technology that translates characters written in magnetic ink into digital codes for processing. </li></ul>
  36. 36. Input Devices <ul><li>Pen-based input: Input devices such as tablets, notebooks, and notepads consisting of a flat-screen display tablet and a pen-like stylus that digitizes handwriting. </li></ul><ul><li>Digital scanners: Input devices that translate images such as pictures or documents into digital form for processing. </li></ul><ul><li>Voice input devices: Technology that converts the spoken word into digital form for processing. </li></ul><ul><li>Sensors: Devices that collect data directly from the environment for input into a computer system. </li></ul>
  37. 37. Batch and On-Line Input and Processing <ul><li>Batch processing: A method of collecting and processing data in which transactions are accumulated and stored until a specified time when it is convenient or necessary to process them as a group. </li></ul><ul><li>On-line processing: A method of collecting and processing data in which transactions are entered directly into the computer system and processed immediately. </li></ul>
  38. 38. A Comparison of Batch & On-line Processing
  39. 39. New Trends in Computer Hardware <ul><li>Multimedia: Technologies that facilitate the integration of two or more types of media such as text, graphics, sound, voice, fulI-motion video, or animation into a computer based application. </li></ul><ul><li>Streaming technology Technology for transferring data so that they can be processed as a steady and continuous stream. </li></ul><ul><li>Network Computers. </li></ul><ul><li>Massively Parallel Computers: Computers that use hundreds or thousands of processing chips to attack large computing problems simultaneously. </li></ul>
  40. 40. New Trends in Computer Hardware <ul><li>Smart card: A credit card-size plastic card containing embedded storage and a microprocessor. </li></ul><ul><li>More Integration. </li></ul><ul><li>Lower Costs. </li></ul><ul><li>Optical computers. </li></ul><ul><li>Solid-state storage devices. </li></ul>