principles of information systems chapter 3 hardware: input, processing, and output devices

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


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


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


Hardware Components

• Central processing unit (CPU)

• Input devices

• Output devices

• Communications devices

• Primary storage devices

• Secondary storage devices


Hardware Components (continued)

Figure 3.1: Hardware Components


• 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


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


Hardware Components in Action (continued)

Figure 3.2: Execution of an Instruction


Hardware Components in Action

• Step 1: Fetch instruction

• Step 2: Decode instruction

• Step 3: Execute instruction

• Step 4: Store results


Hardware Components in Action (continued)


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


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)


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


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


Physical Characteristics of the CPU (continued)

Figure 3.3: Moore’s Law


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)


Storage Capacity

Table 3.1: Computer Storage Units


Types of Memory

• Random access memory (RAM) – Temporary and volatile

• Types of RAM – EDO (Extended Data Out) – DRAM (Dynamic RAM) – SDRAM (Synchronous DRAM)


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



Figure 3.4: Basic Types of Memory Chips



Figure 3.5: Cache Memory


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


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


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


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


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


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)


Devices

• Magnetic tapes

• Magnetic disks

• RAID (Redundant Array of Inexpensive Disk)

• Virtual tape

• Optical disks

• Digital video disk (DVD)

• Holographic versatile disc (HVD)


Devices (continued)

• Memory cards

• Flash memory


Enterprise Storage Options

• Attached storage

• Network-attached storage (NAS)

• Storage area network (SAN)


Enterprise Storage Options (continued)

Figure 3.9: Storage Area Network


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


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


Input Devices

• Personal computer input devices– Keyboard– Mouse

• Speech-recognition technology

• Digital cameras

• Terminals


Input Devices (continued)

• Scanning devices

• Optical data readers

• Magnetic ink character recognition (MICR) devices

• Magnetic stripe card

• Point-of-sale (POS) devices



• Automated teller machine (ATM) devices

• Pen input devices

• Touch-sensitive screens

• Bar-code scanners

• Radio Frequency Identification (RFID)


Output Devices

• Display monitors

• Plasma displays

• Liquid crystal displays (LCDs)

• Organic light-emitting diodes (OLEDs)

• Printers and plotters

• Digital audio player


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


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



• Portable computers

• Thin client



• Desktop computers


Computer System Types (continued)

• Workstations

• Servers



• Servers



• Mainframe computers



• Supercomputers


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


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


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)


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 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 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 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


Review question #3


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