Kenneth J. Sousa Effy Oz

MANAGEMENT

INFORMATION

SYSTEMSSeventh Edition

Chapter 4

Business Hardware

Objectives

• List major hardware components of computers

and explain their functions

• Classify computers into major categories, and

identify their strengths and weaknesses

• Identify and evaluate key criteria for deciding

what computers or related devices to purchase

• Discuss the possible health hazards of computer

use

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Computer Hardware Components

• Hardware: physical components of computers

and related electronic devices

• Consider software before hardware

• Computer must handle four operations:

– Accept data

– Store data and instructions

– Process data

– Output data and/or information

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Computer Hardware Components (cont'd.)

• In general, every computer has the following

components:

– Input devices

– Central processing unit (CPU)

– Internal memory

– Storage

– Output devices

• Input devices: receive signals from outside of

computer and transfer them into the computer

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Figure 4.1 Most computer systems have the same basic components

Computer Hardware Components (cont'd.)

• Central processing unit (CPU)

– Accepts instructions and data

– Decodes and executes instructions

– Stores results (output) in memory

• Internal memory (or primary memory): stores

data and instructions before and after CPU

processes them

– RAM: random access memory

– ROM: read-only memory

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• Motherboard: circuit board containing the CPU

and primary memory

• Storage: magnetic disks, magnetic tapes,

optical discs, DVDs, and flash memory

– Allows permanent storage

• Output devices: deliver information from the

computer to the user

– Monitors and printers are the most common

output devices

– Audio devices also deliver output

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Computer Hardware Components (cont'd.)

• Bit: Binary digit

– 0 or 1

• Byte: a combination of eight bits

• Computer memory and storage capacity are

measured in megabytes (MB), gigabytes (GB),

terabytes (TB), etc.

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Computer Hardware Components (cont'd.)

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Figure 4.2 Measuring amounts of digital data

Classification of Computers

• Computers vary in size and power

• Classified by power

– Power is determined mainly by processing speed

and memory size

• More powerful computers are more expensive

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Supercomputers

• Supercomputers: most powerful computers at

any given time

– Largest in physical size and most expensive

– Designed for complex arithmetic calculations

– Generally impractical for business purposes

• Parallel processing: multiple processors

running simultaneously

– Also known as multiprocessing

– Clustering uses the CPU power of multiple

computers

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Mainframe Computers

• Mainframe computers: store large amounts of

data and business transactions

– Less expensive and less powerful than

supercomputers

– Often used by banks, universities, and insurance

companies as a central computer

– Significant amount of world’s business data

resides on mainframes

– Use multiple processors

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Servers

• Midrange category of computers

• Smaller and less powerful than mainframes

• Serve hundreds of users that connect from

desktops, laptops, and other servers

• Use multiple processors

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Personal Computers (PCs)

• PCs: collective name for several types of

computers

– Notebook, computers, desktops, netbooks, and

handheld computers

• Workstation: more powerful PCs used for CAD,

CAM, complex simulation, graphical rendering,

and scientific applications

• Power of PCs doubles about every two years

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Computers on the Go: Notebooks, Tablets,

and Smartphones

• Notebook computer (or laptop): compact, light

PC powered by rechargeable battery

– Current models include wireless technology

• Personal digital assistant (PDA): handheld

computer

– Stylus: pen-like device used to enter data

through a touch screen

– Smartphone: PDA that is also a mobile phone

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Computers on the Go: Notebooks, Tablets,

and Smartphones (cont’d.)

• Tablet computer: mobile computing device that

uses a touch screen to execute commands

– “Traditional” monitor mode or “slate” mode

– Wide range of applications

– Examples: Apple iPad, Microsoft Surface, and

Kindle Fire

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Converging Technologies

• Technology convergence: building several

technologies into a single piece of hardware

– Prominent in handheld units

• Smartphone is a prime example

– Brings together cellular telephone, data and

networking, media, and cloud storage

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A Peek Inside the Computer

• Professionals must know about computer

components to understand their power and

capabilities

– They use this knowledge to make good decisions

in purchasing or recommending a computer

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The Central Processing Unit

• CPU has two units to store and process data

– Control unit and arithmetic logic unit (ALU)

• CPU is a silicon chip with multiple circuits

• Also known as microprocessor

• Multicore processors: processors that combine

two or more CPUs or “cores” on a single chip

• Multithreading: processing more than one

program, or several parts of a program, at the

same time

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The Central Processing Unit (cont'd.)

• Microprocessors are embedded with transistors

• Transistor: a semiconductor that can represent

binary code’s two states

• Machine cycle: four operations performed by

the CPU

– Fetch, decode, execute and store

• CPU clock: special circuitry on the processor

that synchronizes all tasks

• Clock rate: number of pulses per second

– A machine cycle takes several clock pulses20

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Figure 4.3 What happens inside the CPU in one machine cycle

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Figure 4.4 The timing of computer processing operations

The Central Processing Unit (cont'd.)

• Data word (or word): maximum number of bits

that the control unit can fetch from primary

memory in a single machine cycle

– Current microcomputers have 32- or 64-bit words

• ALU: the part of the CPU that performs

arithmetic and logical operations

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Computer Power

• Depends on processing speed and memory

capacity

• Bus: electronic lines or traces used for

communication inside computer

• Throughput: number of bits per second that the

bus can accommodate

• MIPS (millions of instructions per second): a

common measure of computer speed

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Input Devices

• Computers must receive input to produce output

• Input devices include machines and devices

used to enter instructions and data into

computer

• Common input devices include:

– Keyboard

– Mouse

– Trackball

– Microphone

– Scanner 25

Keyboard

• An input device that contains keys that users

press to enter data

– Includes letters, numbers, punctuation, and

function keys

– QWERTY: standard keyboard layout

– Dvorak: keyboard layout that allows faster typing

• Ergonomics: the study of the comfort and

safety of humans in the workplace

• Ergonomic keyboard: fits the natural position of

forearms and prevents injury

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Mouse, Trackball, and Trackpad

• Mouse: input device that controls an on-screen

pointer to facilitate point-and-click approach

– Has one to five buttons for clicking, locking,

dragging

• Trackball: similar to mouse, but user

manipulates a ball within the device to indicate

movement on the screen

• Trackpad: cursor movement is controlled by

moving a finger over a touch-sensitive pad

• Mice and similar devices can be wireless units

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Touch Screen

• Both an input and an output device

• Often used for public applications, such as

kiosks

• Prevalent in handheld devices, GPS devices,

and mobile phones

• Allows the user to navigate and select by

touching the screen

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Source Data Input Devices

• Copy data directly from sources such as bar

codes, credit cards, and checks

• Optical mark recognition devices detect

positions of marks or characters

• Optical character recognition (OCR) devices try

to interpret handwritten and printed text

• Radio-frequency identification (RFID): fastest

growing source data technology

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Source Data Input Devices (cont'd.)

• Universal Product Code (UPC): bar code on a

product in a grocery store

• Magnetic-ink character recognition (MICR):

automates check processing

• Magnetic strips on credit cards and debit cards

• Bar codes used on packages received through

shipping companies

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Figure 4.5 Banks use magnetic-ink character recognition (MICR) to automate part of the check clearing

process

Imaging

• Converts documents into images

– Saves paper

– More efficient retrieval and filing

• Scanned document images can be:

– Indexed and linked to relevant records in

databases

– Easily retrieved

• Original paper documents can be destroyed

after scanning

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Speech Recognition

• Process of translating human speech into

computer-readable data and instructions

• Also called voice recognition

• System receives input from microphone or

telephone and processes it with software

• Interactive voice recognition (IVR) system:

employed by many companies for customer

service

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Output Devices

• Deliver results of computer processing

• Popular output devices include:

– Monitors

– Printers

– Speakers

• In the future, digital smell output is possible

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Monitors

• Pixel (picture element): small dots that make up

the images on a monitor

• CRT (cathode-ray tube): inner side of screen

has layer of phosphoric dots, i.e., the pixels

– Electron gun receives instructions from computer

and sweeps the pixels

• Flat-panel monitor: advantages include lower

power use, sharper images, and slim profile

• Liquid crystal display (LCD) monitor: uses a

liquid crystal filled screen

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Monitors (cont'd.)

• Monitor price depends on:

– Size, measured as the diagonal length of the

screen

– Brightness → brighter is better

– Contrast ratio → higher is better

– Pixel pitch → closer pixels are better

• Resolution: a measure of picture sharpness

– Number of pixels in the width and height of the

screen

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Figure 4.3 What happens inside the CPU in one machine cycle

Printers

• Nonimpact printer: does not mechanically

impact the paper

– Laser printer is most common in business

– Others include ink-jet and electrothermal printers

– Speed is measured in pages per minute (ppm)

– Density measured in dots per inch (DPI)

• Impact printer: reproduces image by using

mechanical impact

– Dot-matrix printer: tiny pins strike ink ribbon

against paper

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Storage

• Data must be stored on nonvolatile medium

– Data is retained even when the storage device is

not connected to electrical power

• Storage devices differ in the technology used to

maintain data and physical structure

• Evaluate storage devices by comparing:

– Cost

– Capacity

– Access speed

– Access mode38

Modes of Access

• Sequential storage: data is organized one

record after another

– Must read through all records that are stored prior

to the desired record

• Direct access: records are organized by

physical address on the device

– A record can be accessed directly (randomly)

• Flash drive: small storage device that connects

via universal serial bus (USB)

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Figure 4.6 Sequential and direct data access

Magnetic Tapes

• Are similar to tapes used in tape recorders and

VCRs, usually as cartridges

• Provide lowest cost (bytes per dollar)

• Can back up all data

– Takes a long time to copy from tape

• Are unreliable after long periods of time or

usage

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Magnetic Disks

• Most widely used storage medium

– Includes hard disks and floppy disks

• Hard disk: stack of several rigid platters

installed in the same box that holds the CPU

– Internal hard disk in a desktop computer stores

up to three TB of data

– External hard disk connects to computer through

USB port

– Storage provisions for data warehouses

• Large databases

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Optical Discs

• Recorded by treating the disc surface to reflect

light in different ways

• Two basic categories

– Compact discs (CDs)

– Digital video discs (DVDs)

• Compact discs: available as read-only,

recordable, and rewritable

• DVDs: store 4.7 GB per side

• Optical discs are slower than hard disks

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Solid-State Storage

• Also known as flash memory: rewritable

memory chip that holds content without power

– Consumes very little power

– Does not need a constant power supply

– Fast access times

– Relatively immune to shock or vibration

• Available as memory card and USB drive

• Solid state disk (SSD): storage media that does

not have latency time

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DAS, NAS, and SAN

• Direct-attached storage (DAS): disk or array of

disks or tapes directly connected to server

– Easy to deploy and manage; low cost

– Data access speed depends on server usage

• Network-attached storage (NAS): device

designed for networked storage

– Includes both the storage media and the software

to manage it

– Relieves the server of handling storage

– Highly scalable

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DAS, NAS, and SAN (cont'd.)

• Storage area network (SAN): a network fully

devoted to storage and transfer of data

– Managed separately from the rest of the LAN

– May combine DAS and NAS devices

– Can transfer large data blocks at high speeds

– Expensive and complex to manage

• RAID: redundant array of independent disks

– Used by DAS, NAS, and SAN

– Fault-tolerant: system’s ability to sustain a disk

failure because the same data is on another disk

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Cloud Storage

• Availability of network-accessible storage from

an off-site computer or technology device

• Systems are usually maintained by a third-party

organization through a subscription charge

• Storage-as-a-service: cloud storage vendors

• Advantages: reduces cost of storing and

managing data; frees internal storage

infrastructure for live and production data

• Disadvantages: reliance on networks and their

costs; and risks of security breaches

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Business Considerations in Evaluating Storage

Media

• When purchasing storage devices, managers

must consider:

– Purpose of data storage

– Amount of data to be stored

– Required speed of data storage and retrieval

– Unit space and portability of the device

– Cost

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Figure 4.7 Characteristics of digital storage media for business purposes

Considerations in Purchasing Hardware

• Equipment’s power: speed, memory size, and

capacity

• Expansion slots and ports: numbers and types

– Ports: sockets that connect external devices to a

computer

• Monitor type and resolution

• Ergonomics

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Considerations in Purchasing Hardware

(cont'd.)

• Compatibility

– With existing hardware, software, and networks

– Backward compatibility: newer hardware works

with older hardware

• Hardware footprint: area that it requires

• Reliability of vendor, warranty policy and

post-warranty support

• Power consumption and noise

• Cost

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Figure 4.8 Example of an evaluation form to assist with the purchase of hardware

Scalability and Updating Hardware

• Principle of scalability

– Resources—in this case, hardware—can

accommodate a growing amount of work either

with or without upgrading

• Not all hardware is scalable

• Hardware replacement is needed to avoid

performance gaps between hardware and

software

• Leasing hardware is a valid option to avoid short

useful lifetime of hardware

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Summary

• Understanding hardware is important for

purchasing decisions

• Computers are classified according to power

• All computers have a CPU to process

instructions

• Clock rate measures the speed of a CPU

• Data word: the number of bits the computer can

process in a single cycle

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Summary (cont'd.)

• Computer power: measured by its speed,

memory size, and number of processor cores

• RAM: volatile memory

• ROM is nonvolatile; it does not require power

• Imaging devices help process text and graphics

• When evaluating external storage, consider

transfer rate, capacity, portability, and form of

data organization supported

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Summary (cont'd.)

• Data is organized sequentially on tapes

• Direct access storage devices such as RAM,

magnetic disks, and optical discs allow random

access

• Databases require direct access storage devices

• When purchasing hardware, professionals

should consider cost, power, scalability,

compatibility, etc.

• Information technology may pose health risks

such as carpal tunnel syndrome

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