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Principles of Information Systems
Chapter 3
Hardware: Input, Processing, and Output Devices
Principles of Information Systems 3
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
Principles of Information Systems 4
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
Principles of Information Systems 5
Computer Systems: Integrating The Power of Technology
• Choosing the right computer hardware requires understanding its relationship to the information system and needs of the organization
• Hardware objectives are subordinate to, but supportive of, the information system and the current and future needs of the organization
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Hardware Components
• Central processing unit (CPU)
• Input devices
• Output devices
• Communications devices
• Primary storage devices
• Secondary storage devices
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Hardware Components (continued)
Figure 3.1: Hardware Components
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• Hardware Components– Central processing unit (CPU)
• Arithmetic/logic unit, the control unit, and the register areas
– Arithmetic/logic unit (ALU) • Performs mathematical calculations and makes logical
comparisons
8
Hardware Components
Principles of Information Systems 9
Hardware Components (continued)
– Control unit • Sequentially accesses program instructions, decodes
them, and coordinates the flow of data in and out of the ALU, registers, primary storage, and even secondary storage and various output devices
– Registers • High-speed storage areas
– Primary storage• Closely associated with the CPU
Principles of Information Systems, Ninth Edition 9
Principles of Information Systems 10
Hardware Components in Action (continued)
Figure 3.2: Execution of an Instruction
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Hardware Components in Action
• Step 1: Fetch instruction
• Step 2: Decode instruction
• Step 3: Execute instruction
• Step 4: Store results
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Hardware Components in Action (continued)
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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
• Machine cycle time is measured in:– Nanoseconds (1 billionth of a second)– Picoseconds (1 trillionth of a second)– MIPS (millions of instructions per second)
Principles of Information Systems 15
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
Principles of Information Systems 16
Physical Characteristics of the CPU
• Digital circuits on chips
• Electrical current flows through silicon
• Moore’s Law: transistor density of chips will double every 18 months
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Physical Characteristics of the CPU (continued)
Figure 3.3: Moore’s 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
• Storage Capacity– Eight bits together form a byte (B)
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Storage Capacity
Table 3.1: Computer Storage Units
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Types of Memory
• Random access memory (RAM) – Temporary and volatile
• Types of RAM – EDO (Extended Data Out) – DRAM (Dynamic RAM) – SDRAM (Synchronous DRAM)
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Types of Memory (continued)
• Types of nonvolatile memory– ROM (read-only memory)– PROM (programmable read-only memory)– EPROM (erasable programmable read-only
memory)
• Cache memory: high-speed memory that a processor can access more rapidly than main memory
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Types of Memory (continued)
Figure 3.4: Basic Types of Memory Chips
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Types of Memory (continued)
Figure 3.5: Cache Memory
Principles of Information Systems 24
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
• Multicore microprocessor – Combines two or more independent processors
into a single computer
Principles of Information Systems 25
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
Principles of Information Systems 26
Parallel Computing (continued)
• 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
Principles of Information Systems 27
Parallel Computing (continued)
• Cloud computing – Uses giant cluster of computers, that serves as a
host, to run applications that require high-performance computing
– Supports a wider variety of applications than grid computing
– Pools computing resources so they can be managed primarily by software rather than people
Principles of Information Systems, Ninth Edition 27
Principles of Information Systems 28
Secondary Storage
• Compared with memory, offers the advantages of nonvolatility, greater capacity, and greater economy
• Access methods, storage capacities, and portability required are determined by the information system’s objectives
Principles of Information Systems 29
Access Methods
• Sequential access: records must be retrieved in order– 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
• RAID (Redundant Array of Inexpensive Disk)
• Virtual tape
• Optical disks
• Digital video disk (DVD)
• Holographic versatile disc (HVD)
Principles of Information Systems 31
Devices (continued)
• Memory cards
• Flash memory
Principles of Information Systems 32
Enterprise Storage Options
• Attached storage
• Network-attached storage (NAS)
• Storage area network (SAN)
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Enterprise Storage Options (continued)
Figure 3.9: Storage Area Network
Principles of Information Systems 34
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
Principles of Information Systems 35
Characteristics and Functionality
• 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
Principles of Information Systems 36
Input Devices
• Personal computer input devices– Keyboard– Mouse
• Speech-recognition technology
• Digital cameras
• Terminals
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Input Devices (continued)
• Scanning devices
• Optical data readers
• Magnetic ink character recognition (MICR) devices
• Magnetic stripe card
• Point-of-sale (POS) devices
Principles of Information Systems 38
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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Input Devices (continued)
Principles of Information Systems 40
Output Devices
• Display monitors
• Plasma displays
• Liquid crystal displays (LCDs)
• Organic light-emitting diodes (OLEDs)
• Printers and plotters
• Digital audio player
Principles of Information Systems 41
Special-Purpose Input and Output Devices
• Multiple function printers
• E-books - Computer-based navigation systems– Digital media equivalent of a conventional printed
book
• Eyebud screens– Portable media devices that display video in front of
one eye
Principles of Information Systems 42
Computer System Types, Selection, and Upgrading
• Special-purpose computers: used for limited applications by military and scientific research groups
• General-purpose computers: used for a wide variety of applications
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Computer System Types
• Handheld computers
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Computer System Types
• Portable computers
• Thin client
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Computer System Types
• Desktop computers
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Computer System Types (continued)
• Workstations
• Servers
Principles of Information Systems 47
Computer System Types (continued)
• Servers
Principles of Information Systems 48
Computer System Types (continued)
• Mainframe computers
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Computer System Types (continued)
• Supercomputers
Principles of Information Systems 50
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
Principles of Information Systems 51
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
Principles of Information Systems 52
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)
Principles of Information Systems 53
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.
Principles of Information Systems 54
Principles of Information Systems 55
Principles and Learning Objectives
• Assembling an effective, efficient set of computer hardware devices requires understanding their role in supporting the underlying information systems and the needs of the organization; the computer hardware objectives are subordinate to, but supportive of, the information systems and the needs of the organization
Principles of Information Systems 56
Principles and Learning Objectives (continued)
• When selecting computer hardware, you must consider the current and future needs of the information systems and the organization; your choice of a hardware device should always allow for later improvements to meet evolving organizational needs
Principles of Information Systems 57
Principles and Learning Objectives (continued)
– 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
Principles of Information Systems 58
Review question #3
Principles of Information Systems 59
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