Principles of Information Systems Eighth Edition

1
Principles of Information SystemsEighth Edition

• Hardware
• Input, Processing, and
• Output Devices

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Learning Objectives

• Describe how to select and organize computer
  hardware components to support information system
  (IS) objectives and business needs
• Describe the power, speed, and capacity of
  central processing and memory devices
• Describe the access methods, capacity, and
  portability of secondary storage devices
• Discuss the speed, functionality, and importance
  of input and output devices
• Identify popular classes of computer systems and
  discuss the role of each

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Why Learn About Hardware?

• Can improve productivity, increase revenue,
  reduce costs, and provide better service
• Managers are expected to know about hardware
• To help define business needs
• To ask questions and evaluate options when buying
  equipment

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Introduction

• Hardware any machinery (most of which use
  digital circuits) that assists in the input,
  processing, storage, and output activities of an
  information system
• When making hardware decisions, businesses must
  consider how the hardware can support
• Objectives of the information system
• Goals of the organization

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Hardware Devices Analogy A Paper-Based Office
Register Storage
Output
Primary Storage
Secondary Storage
Input
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Hardware Components
Figure 3.1 Hardware Components
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Hardware Components in Action

• Execution of machine-level instruction
• Phase 1 Instruction Phase Fetch and Decode
• Phase 2 Execution Phase Execute and Store
• I-time the time taken to perform phase 1
• E-time the time taken to perform phase 2

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Hardware Components in Action
Figure 3.2 Execution of an Instruction
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Processing and Memory Devices Power, Speed, and
Capacity

• System unit
• Houses the components responsible for processing
  (the CPU and memory)
• All other computer system devices are linked
  either directly or indirectly into the system
  unit housing

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Processing Characteristics and Functions

• Computer execute an instruction during a machine
  cycle
• Completing the instruction and execution phase
  make up one machine cycle
• Machine cycle time is measured in
• Nanoseconds (1 billionth of a second)
• Picoseconds (1 trillionth of a second)
• MIPS (millions of instructions per second)

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Processing Characteristics and Functions
(continued)

• Clock speed series of electronic pulses produced
  at a predetermined rate that affects machine
  cycle time
• Often measured in
• Megahertz (MHz) millions of cycles per second
• Gigahertz (GHz) billions of cycles per second
• Microcode predefined, elementary circuits and
  logical operations that the processor performs
  when it executes an instruction

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Physical Characteristics of the CPU

• Collection of digital circuits on chips
• Electrical current flows through silicon to
  turn the digital circuit on or off
• Gordon Moore former Intels chairman
  hypothesised that progress in chip manufacturing
  transistor density of chips will double every 18
  months (Moores Law)

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Physical Characteristics of the CPU (continued)
Figure 3.3 Moores Law
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Memory Characteristics and Functions

• Main memory
• Located physically close to the CPU, but not on
  the CPU chip itself
• Rapidly provides data and instructions to the CPU

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Storage Capacity
Table 3.1 Computer Storage Units
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Types of Memory
Figure 3.4 Basic Types of Memory Chips
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Types of Memory (Cash Memory)
Figure 3.5 Cache Memory
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Multiprocessing

• Multiprocessing simultaneous execution of two or
  more instructions at the same time
• Multiprocessing using coprocessors
• Coprocessor speeds processing by executing
  specific types of instructions while the CPU
  works on another processing activity

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Parallel Computing

• Parallel computing simultaneous execution of the
  same task on multiple processors to obtain
  results faster
• Massively parallel processing
• Speeds processing by linking hundreds or
  thousands of processors to operate at the same
  time, or in parallel
• Each processor has its own bus, memory, disks,
  copy of the operating system, and applications

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Parallel Computing (continued)

• 2 different approaches to achieving parallel
  computing
• Single instruction/multiple data (SIMD) parallel
  processors
• Multiple instruction/multiple data (MIMD)
  parallel processors
• Grid computing use of a collection of computers,
  often owned by multiple individuals or
  organizations, to work in a coordinated manner to
  solve a common problem

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Secondary Storage

• Permanent storage
• Compared with memory, offers the advantages of
  nonvolatility, greater capacity, and greater
  economy
• Selection of secondary storage access methods,
  storage capacities, and portability required -
  determined by the information systems objectives
• Example credit card company

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Access Methods

• Two types of access methods
• Sequential access records must be retrieved in
  order in which its stored
• Devices used are called sequential access storage
  devices (SASDs)
• Direct access records can be retrieved in any
  order
• Devices used are called direct access storage
  devices (DASDs)

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Devices

• Magnetic tapes
• Magnetic disks
• Optical disks
• Digital video disk (DVD)
• Holographic Versatile Disc (HVD)
• Memory cards
• Flash memory
• RAID
• Virtual tape

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Magnetic Tapes

• Sequential secondary storage medium
• Primarily for storing backups
• Tapes similar to audio and videocassettes
• Portion of tapes are magnetized to represent bits

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Magnetic Disks

• Direct access storage medium
• e.g. diskette, hard disks
• Allows fast data retrieval

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Optical Disc

• Data is recorded by special lasers that
  physically burn pits in the disk.
• Data accessed optical disc device (compact disk
  player)
• e.g. CD-ROM 740MB, CD-RW

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DVD and HVD

• DVD (Digital Video Disc)
• Looks like a CD but more storage capacity
  135min of digital video.
• Software, video games, movies
• HVD (Holographic Versatile Disc)
• Advanced optical disk ongoing research
• Hold 200GB of data
• Write data 10 times faster than DVD

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Memory cards

• Functions as a hard disk drive
• Portable, relatively easy to use
• Need to use memory card reader/writer

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Flash Memory

• A silicon computer chip
• Keeps its memory when the power is shut off
• Flash the memory cell is erased or
  reprogrammed in a single action or flash
• e.g. Migo keychain device, comes with
  software that captures files and settings from
  e-mail, word processing, web browser,
  presentation programs.

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RAID and Virtual Tape

• Storage technologies
• RAID
• Redundant array of independent /inexpensive disks
• duplicate existing data on drives, provides exact
  copy, store on different physical disk drives
• Virtual Tape
• manages less frequently needed data
• Move data to less costly storage media
• Software virtual tape server
• Vendor IBM and Storage Technology

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Enterprise Storage Options

• Needs to store massive amount of data
• 3 forms
• Attached storage
• tape, hard disks, optical devices
• Simple, cost effective - single users and small
  groups
• Not allowed share storage
• Network-attached storage (NAS)
• Storage devices attach to a network
• Users can share and access same information

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Enterprise Storage Options (continued)

• Storage area network (SAN)
• Special purpose, high speed network
• Provides direct connections between data-storage
  devices and computer
• Integrates different types of storage subsystems

Figure 3.9 Storage Area Network (SAN)
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Input and Output Devices The Gateway to Computer
Systems

• Through input and output devices, people provide
  data and instructions to the computer and receive
  results from it
• Selection of input and output devices depends on
  organizational goals and IS objectives

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Characteristics and Functionality

• Nature of data- data can be human-readable or
  machine-readable
• Data entry converts human-readable data into
  machine-readable form
• Data input transfers machine-readable data into
  system
• Source data automation capturing and editing
  data where the data is initially created and in a
  form that can be directly input to a computer

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Input Devices

• Personal computer input devices
• Keyboard
• Mouse
• Speech-recognition technology
• Input devices that recognize human speech
• e.g. automate account identification process
• Digital cameras
• Terminals
• Input and display devices that perform data entry
  and input at same time
• Office, warehouse, factory

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Input Devices (continued)

• Scanning devices
• Optical data readers
• Special scanner
• OMR standardized tests
• OCR convert handwritten to typed doc into
  digital data
• Magnetic stripe card
• Swipe card
• Point-of-sale (POS) devices
• Used in retail operations to enter sales
• information

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• Magnetic ink character recognition (MICR) devices
• A system for reading banking data quickly
• Use special ink readable by people and computers
• e.g. bank check

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Input Devices (continued)

• Automated teller machine (ATM) devices
• Pen input devices
• Touch-sensitive screens
• Bar-code scanners
• Radio Frequency Identification (RFID)

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Output Devices

• Display monitors
• Liquid crystal displays (LCDs)
• Organic light-emitting diodes (OLEDs)
• Printers and plotters
• Digital audio player

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Special-Purpose Input and Output Devices

• Computer-based navigation systems
• GPSs (Global positioning system), satellite based
  radio navigating system
• Guide to specific destination
• Multiple function printers
• Print, copy, fax,scan
• Eyebud screens
• Portable media devices
• Display video in front of one eye

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Computer System Types, Selection, and Upgrading

• Computer classification
• Special-purpose computers used for limited
  applications by military and scientific research
  groups
• General-purpose computers
• used for a wide variety of applications
• Single user at a time, multiple concurrent users

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Computer System Types

• Handheld computers single user, small size,
  portable
• Portable computers
• laptops, notebooks, tablet
• Thin client
• Low-cost, no extra drives, limited capabilities
• Desktop computers

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Computer System Types (continued)

• Workstations more powerful than personal
  computer, similar size to desktop, heavy
  mathematical computing, CAD.
• Servers to perform special tasks, e.g. running
  network or Internet application.

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Computer System Types (continued)

• Mainframe computers large, powerful computer,
  shared by hundreds of concurrent users, connected
  via terminals
• Supercomputers
• most powerful computers, fastest processing
  speed, highest performance.
• Special purpose machines weather forecast,
  military application, simulation of golf club
  designs.

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Selecting and Upgrading Computer Systems

• Dispose of old equipment properly
• Consider factors such as speed, cost, and
  performance when upgrading
• Hard drive
• Main memory
• Printer
• DVD burners

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Summary

• Hardware machinery that assists in the input,
  processing, storage, and output activities of an
  information system
• Hardware components central processing unit
  (CPU), input and output devices, communications
  devices, primary storage devices, and secondary
  storage devices
• Random access memory (RAM) temporary and
  volatile
• ROM (read-only memory) nonvolatile

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Summary (continued)

• Multiprocessing simultaneous execution of two or
  more instructions at the same time
• Sequential access records must be retrieved in
  order
• Direct access records can be retrieved in any
  order
• Examples of secondary storage devices magnetic
  tapes and disks, DVDs, memory cards, etc.
• Enterprise storage options attached storage,
  network-attached storage (NAS), and storage area
  network (SAN)

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Summary (continued)

• Examples of input devices keyboards, mice,
  voice-recognition devices, terminals, scanning
  devices, and touch-sensitive screens
• Examples of output devices display monitors,
  liquid crystal displays (LCDs), printers, and
  plotters
• Computers can be classified as either
  special-purpose or general-purpose
• Computer system types handheld computers,
  portable computers, desktop computers,
  workstations, servers, etc.