Hardware: Input, Processing, & Output Devices Chapter 3

IS for Management2 Hardware 4 Hardware Any machinery (most of which uses digital circuits) that assists in the input, processing, storage, & output activities of an information system

Chapter 3IS for Management3 4 Central Processing Unit (CPU) A hardware component that performs computing functions utilizing the ALU, control unit, & registers 4 Arithmetic/Logic Unit (ALU) Performs mathematical calculations & makes logical comparisons 4 Control Unit Sequentially accesses program instructions, decodes them, coordinates flow of data in/out of ALU, registers, primary & secondary storage, & various output devices Hardware Components (1)

Chapter 3IS for Management4 Hardware Components (2) 4 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)

Chapter 3IS for Management5 Hardware Components (Figure 3.1)

Chapter 3IS for Management6 Execution of an Instruction See also Figure 3.2 Machine Cycle - Instruction phase - Execution phase 4 Instruction Phase –Step 1: Fetch instruction –Step 2: Decode instruction Instruction time: The time to complete the instruction phase. 4 Execution Phase –Step 3: Execute instruction –Step 4: Store results Execution time: The time to complete the execution phase.

Chapter 3IS for Management7 Machine Cycle Time See Figure Machine Cycle Time Time it takes to execute an instruction 4 Slow machines Measured in microseconds (one-millionth of a second) 4 Fast machines Measured in nanoseconds (one-billionth of a second) to picoseconds (one-trillionth of a second) 4 MIPS Millions of instructions per second. 4 Pipelining A CPU operation in which multiple execution phases are performed in a single machine cycle

Chapter 3IS for Management8 Clock Speed 4 Clock Speed Predetermined rate a CPU produces a series of electronic pulses. 4 Hertz One cycle or pulse per second 4 Megahertz (MHz) Millions of cycles per second

Chapter 3IS for Management9 Wordlength 4 Wordlength Number of bits the CPU can process at any one time 4 BIT Binary Digit - 0s & 1s that combine to form a “word” 4 Computer word What the computer processes 4 Microcode Predefined, elementary circuits & logical operations that the processor performs when it executes an instruction.

Chapter 3IS for Management10 Bus Line 4 Bus Line Physical wiring connecting computer components 4 Bus Line Width Number of bits a bus line can transfer at one time.

Chapter 3IS for Management11 Moore’s Law (Figure 3.4) Moore’s Law A hypothesis that states transistor densities in a single chip will double every 18 months

Chapter 3IS for Management12 Instruction Sets 4 Complex instruction set computing (CISC) A computer chip design that places as many microcode instructions into the central processor as possible 4 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

Chapter 3IS for Management13 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.

Chapter 3IS for Management14 Memory Characteristics & Functions (Figure 3.5) 4 Temporary & volatile: RAM - Random Access Memory SRAM DRAM 4 Permanent & non-volatile: ROM - Read Only Memory PROM EPROM 4 Cache memory (See Figure 3.6) High speed memory that a processor can access more rapidly than main memory.

Chapter 3IS for Management15 Multiprocessing 4 Multiprocessing The simultaneous execution of two or more instructions at the same time. 4 Coprocessor Speeds processing by executing specific types of instructions while the CPU works on another processing activity.

Chapter 3IS for Management16 Parallel Processing (Figure 3.7) 4 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., uses both cached information & parallel processing via hundreds of desktop computers.

Chapter 3IS for Management17 Secondary Storage Stores large amounts of data, instructions, & information more permanently than main memory. 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 Devices for Secondary Storage

Chapter 3IS for Management18 Access Methods & Storage Devices 4 Sequential Data retrieved in the order stored. 4 Direct Data retrieved without the need to read or pass other data in sequence. 4 Storage Devices –Sequential Access Storage Devices (SASDs) –Direct Access Storage Devices (DASDs)

Chapter 3IS for Management19 Input & Output Devices 4 Data entry The process by which human-readable data is converted into machine-readable form 4 Data input The process of transferring machine-readable data into the computer system 4 Source data automation Capturing & editing data where the data is originally created & in a form that can be directly input to a computer

Chapter 3IS for Management20 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

Chapter 3IS for Management21 Output Devices Display monitors Liquid crystal displays (LCDs) Printers & plotters Computer output microfilm (COM) Disks & diskettes

Chapter 3IS for Management22 Types of Computer Systems (1) 4 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 4 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.

Chapter 3IS for Management23 Types of Computer Systems (2) 4 Mainframe Computers –Large & powerful –Shared by hundreds/thousands concurrently –Useful for large orgs., massive transaction processing (e.g., Internet gateway, credit card authorisation) 4 Supercomputers –Most powerful –with fastest processing speeds –Useful for massive number crunching (e.g., simulating wind tunnel)

Chapter 3IS for Management24 Types of Computer Systems (3) 4 Computer System Architecture The structure, or configuration, of the hardware components of a computer system 4 Multimedia Computer System (See Figure 3.17) –Marriage of sound, animation, & digitized video – What is the multimedia part of the Internet commonly known as?

Chapter 3IS for Management25 Annual Cost of PC Ownership (TCO) (See Figure 3.16) 4 Hardware15% 4 Technical support 15% 4 Administration services15% 4 End user operations55%

Chapter 3IS for Management26 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

Chapter 3IS for Management27 Case 4 Unisys - customer service, pages Next Class Chapter Four: Software Case: Gap uses object-oriented programming pp