Hardware: Input, Processing, & Output Devices

1. Chapter 3 Hardware: Input, Processing, & Output Devices

2. Hardware • Hardware Any machinery (most of which uses digital circuits) that assists in the input, processing, storage, & output activities of an information system IS for Management

3. Hardware Components (1) • Central Processing Unit (CPU) A hardware component that performs computing functions utilizing the ALU, control unit, & registers • Arithmetic/Logic Unit (ALU) Performs mathematical calculations & makes logical comparisons • Control Unit Sequentially accesses program instructions, decodes them, coordinates flow of data in/out of ALU, registers, primary & secondary storage, & various output devices IS for Management

4. Hardware Components (2) • Registers • High-speed storage areas used to temporarily hold small units of program instructions & data immediately before, during, & after execution by the CPU • Primary Storage • Holds program instructions & data (a.k.a. main memory) IS for Management

5. Hardware Components (Figure 3.1) IS for Management

6. Machine Cycle - Instruction phase - Execution phase Execution of an InstructionSee also Figure 3.2 • Instruction Phase • Step 1: Fetch instruction • Step 2: Decode instruction • Execution Phase • Step 3: Execute instruction • Step 4: Store results Instruction time: The time to complete the instruction phase. Execution time: The time to complete the execution phase. IS for Management

7. Machine Cycle TimeSee Figure 3.3 • Machine Cycle Time Time it takes to execute an instruction • Slow machines Measured in microseconds (one-millionth of a second) • Fast machines Measured in nanoseconds (one-billionth of a second) to picoseconds (one-trillionth of a second) • MIPS Millions of instructions per second. • Pipelining A CPU operation in which multiple execution phases are performed in a single machine cycle IS for Management

8. Clock Speed • Clock Speed Predetermined rate a CPU produces a series of electronic pulses. • Hertz One cycle or pulse per second • Megahertz (MHz) Millions of cycles per second IS for Management

9. Wordlength • Wordlength Number of bits the CPU can process at any one time • BIT Binary Digit - 0s & 1s that combine to form a “word” • Computer word What the computer processes • Microcode Predefined, elementary circuits & logical operations that the processor performs when it executes an instruction. IS for Management

10. Bus Line • Bus Line • Physical wiring connecting computer components • Bus Line Width • Number of bits a bus line can transfer at one time. IS for Management

11. Moore’s Law(Figure 3.4) Moore’s Law A hypothesis that statestransistor densities in a single chip will double every 18 months IS for Management

12. Instruction Sets • Complex instruction set computing (CISC) A computer chip design that places as many microcode instructions into the central processor as possible • Reduced instruction set computing (RISC) A computer chip design based on reducing the number of microcode instructions built into a chip to an essential set of common microcode instructions IS for Management

13. Byte Eight bits together that represent a single character of data. Bytes are stored in memory. Memory provides working storage for program instructions. • Storage • Data is represented in on/off (0/1) circuit states. 1 2 3 4 5 6 7 8 IS for Management

14. Memory Characteristics & Functions(Figure 3.5) • Temporary & volatile: RAM - Random Access Memory • SRAM • DRAM • Permanent & non-volatile: ROM - Read Only Memory • PROM • EPROM • Cache memory(See Figure 3.6) High speed memory that a processor can access more rapidly than main memory. IS for Management

15. Multiprocessing • Multiprocessing • The simultaneous execution of two or more instructions at the same time. • Coprocessor • Speeds processing by executing specific types of instructions while the CPU works on another processing activity. IS for Management

16. Parallel Processing(Figure 3.7) • Parallel processing • A form of multiprocessing that speeds the processing by linking several processors to operate at the same time or in parallel • Splits task to be processed by multiple processors, then solutions are compiled/ combined to provide a result • e.g., www.google.com uses both cached information & parallel processing via hundreds of desktop computers. IS for Management

17. Secondary Storage Stores large amounts of data, instructions, & information more permanently than main memory. Devices for Secondary Storage • Magnetic tape • Magnetic disks • Compact Disk Read-Only • Memory (CD-ROM) • Write Once Read Many - (WORM) • Magneto-optical disks • Redundant Array of Independent / Inexpensive Disks (RAID) • Optical disks • Digital Video Disks • Memory cards • Flash memory • Removable storage • See Figures 3.9, 3.10, 3.11 & 3.12 IS for Management

18. Access Methods & Storage Devices • Sequential • Data retrieved in the order stored. • Direct • Data retrieved without the need to read or pass other data in sequence. • Storage Devices • Sequential Access Storage Devices (SASDs) • Direct Access Storage Devices (DASDs) IS for Management

19. Input & Output Devices • Data entry The process by which human-readable data is converted into machine-readable form • Data input The process of transferring machine-readable data into the computer system • Source data automation Capturing & editing data where the data is originally created & in a form that can be directly input to a computer IS for Management

20. Input Devices • PC input devices • Voice recognition devices • Digital computer cameras • Terminals • Scanning devices • Optimal data readers • Magnetic Ink Character Recognition (MICR) • Point Of Sale (POS) devices • Automatic Teller Machine (ATM) • Pen input devices • Light pens • Touch sensitive screens • Bar code scanners IS for Management

21. Output Devices • Display monitors • Liquid crystal displays (LCDs) • Printers & plotters • Computer output microfilm (COM) • Disks & diskettes IS for Management

22. Types of Computer Systems (1) • Personal Computers (PCs) or Microcomputers • Small, relatively inexpensive • Desktop , laptop, or notebook • Different degrees of power & cost • Network Computers for accessing networks, especially the Internet (also known as network appliances) • Workstations are high-end microcomputers • Minicomputers • Size of a three drawer file cabinet plus peripherals • accommodates several users at one time • Useful for departments of large orgs. or entire mid-size orgs. IS for Management

23. Types of Computer Systems (2) • Mainframe Computers • Large & powerful • Shared by hundreds/thousands concurrently • Useful for large orgs., massive transaction processing (e.g., Internet gateway, credit card authorisation) • Supercomputers • Most powerful • with fastest processing speeds • Useful for massive number crunching (e.g., simulating wind tunnel) IS for Management

24. Types of Computer Systems (3) • Computer System Architecture The structure, or configuration, of the hardware components of a computersystem • Multimedia Computer System(See Figure 3.17) • Marriage of sound, animation, & digitized video • What is the multimedia part of the Internet commonly known as? IS for Management

25. Annual Cost of PC Ownership (TCO) (See Figure 3.16) • Hardware 15% • Technical support 15% • Administration services 15% • End user operations 55% IS for Management

26. Industry Standards in Common Use Computer standards: reference models used by various groups to establish interoperability between computer components • Multimedia Extension (MMX) • Multimedia PC Council (MPC) • Ultimedia Solution • Musical Instrument Digital Interface (MIDI) • Plug ‘n’ Play (PnP) • Small Computer System Interface (SCSI) • Fibre Channel • Personal Computer Memory Card International Association • (PCMCIA) • Universal Serial Bus (USB) • Firewire IS for Management

27. Case • Unisys - customer service, pages 132-133 Next Class Chapter Four: Software Case: Gap uses object-oriented programming pp. 184-185 IS for Management