David Kroenke Hardware and Software Chapter 3 © 2007 Prentice Hall, Inc. 1

David Kroenke

Hardware and Software

Chapter 3

© 2007 Prentice Hall, Inc. 1

Learn the terminology necessary to be an intelligent consumer of hardware products.

Know the functions and basic features of common hardware devices.

Understand the essentials of the representation of computer instructions and data.

Know the purpose of the CPU and main memory, and understand their interaction.


Learn about viruses, Trojan horses, and worms and how to prevent them.

Understand the key factors that affect computer performance.

Learn basic characteristics of the four most popular operating systems.

Know the sources and types of application software.


Computing devices consists of computer hardware and software.

Hardware is electronic components and related gadgetry that input, process, output, and store data according to instructions encoded in computer programs or software.

Your personal computer and other computers like it are general-purpose computers.◦ They can run different programs to perform

different functions.


Some computers are special-purpose computers.◦ The programs they run are fixed permanently in

memory.◦ The computer in your cell phone is a special-

purpose computer, and so is the computer in your car that meters fuel to your car’s engine.


The principles and fundamental components of general-purpose and special-purpose computers are the same;◦ The sole difference is the computer can process a

variety of different programs


One easy way to categorize hardware is by its primary function:◦ Input hardware◦ Processing hardware◦ Output hardware◦ Storage hardware◦ Communication hardware



Input hardware devices are the keyboard, mouse, document scanners, and bar-code (Universal Product Code) scanners.

Microphones also are input devices; with tablet PCs, human handwriting can be input as well.

Processing devices include the central processing unit (CPU), which is sometimes called “the brain” of the computer.



The CPU selects instructions, processes them, performs arithmetic and logical comparisons, and stores results of operations in memory.

CPU’s vary in speed, function, and cost.

Whether you or your department needs the latest, greatest CPU depends on the nature of your work.

The CPU works in conjunction with main memory.


The CPU reads data and instructions from memory, and it stores results of computations in main memory.

Computers also can have special function cards that can be added to the computer to augment the computer’s basic capabilities.◦ A common example is a card that provides

enhanced clarity and refresh speed for the computer’s video display.



Output hardware consists of video displays, printers, audio speakers, overhead projectors, and other special-purpose devices, such as large flatbed plotters.

Storage hardware saves data and programs.

Magnetic disk is by far the most common storage device, although optical disks, such as CDs and DVDs are popular.

In large corporate data centers, data are sometimes stored on magnetic tape.


Computers represent data using binary digits, called bits.

A bit is either a zero or a one.

Bits are used for computer data because they are easy to represent physically.

A switch can either be closed or open.


A computer can be designed so an open switch represents zero and a closed switch represents a one.

Or, the orientation of a magnetic field can represent a bit;◦ Magnetism in one direction represents a zero◦ Magnetism in the opposite direction represents a

one

Or, for optical media, small pits are burned onto the surface of the disk so that they will reflect light◦ In a given spot, a reflection means a one◦ No reflection means a zero



Computers use bits for two purposes: instructions and data.

A given instruction, say to add two numbers together, is represented by a string of digits (0111100010001110).

When the CPU reads such an instruction from main memory, it adds the numbers or takes whatever action the instruction specifies.

The collection of instructions that a computer can process is called the computer’s instruction set.


All of the personal computers that run Microsoft Windows are based on an instruction set developed by Intel Corporation that is called Intel instruction set.

Until 2006, all Macintosh computers used a different instruction set, the PowerPC instruction set, designed for Powerful PC processors.

In 2006, Apple began offering Macintosh computers with a choice of either Intel or PowerPC processors.


Currently, you cannot run a program designed for one instruction set on a computer having a different instruction set.

In the future, you may be able to run Windows on a Macintosh that uses the Intel instruction set, although the particulars of that are uncertain.

When you pick a family of computers, such as Windows or the Macintosh, you pick not only the hardware, but also the sets of programs that can run on one family of computers.


All computer data are represented by bits.

The data can be numbers, characters, currency amounts, photos, recordings, or whatever.

Bits are grouped into 8-bit chunks called bytes.

For character data, such as letters in a person’s name, one character will fit into one byte.◦ Thus, when you read a specification that a computing

device has 100 million bytes of memory, you know that the device can hold 100 million characters.



It is not possible to determine the type of computer data just by looking at the data.◦ The bit string 01000001 can be interpreted as the

decimal number 65, as the character A, or as part of a picture or a sound file.

◦ Further, it could be part of a computer instruction.

The CPU determines how to interpret a bit string from the context in which it encounters it.

If the string occurs in the context of reading instructions, it will be interpreted as a computer instruction.


If it occurs in the context of reading instructions, it will be interpreted as the character A.

If it occurs during arithmetic operations, it will be interpreted as the number 65.

This ambiguity is more than curiosity; virus authors and other cyber-criminal use it to their advantage.


Suppose that your IS department states that you can buy three different computer configurations for three different prices.

The computers are described by expressions like the following:◦ Intel Pentium 4 Processor at 2.8 GHz with 533MHz

Data Bus and 512K cache, 256MB RAM◦ Intel Pentium 4 Processor at 2.8 GHz with 533MHz

Data Bus and 512K cache, 512 MB RAM◦ Intel Pentium 4 Processor at 3.6 GHz with 533MHz

Data Bus and 1MB cache, 256 MB RAM


Now, you, have two choices:◦ You can tell the people in the IS department to

specify what they think is best;◦ Or, with a little bit of knowledge on your part, you

can work with the IS department to ask intelligent questions about the relationship of these computers to the kind of work your department does



The motherboard is a circuit board upon which the processing components are mounted and/or connected.

The central processing unit (CPU) reads instructions and data from main memory, and it writes data to main memory via a data channel, or bus.

Main memory consists of a set of cells, each of which holds a byte of data or instruction.


Each cell has an address, and the CPU uses the addresses to identify particular data items.

Main memory is also called RAM memory, or just RAM.

RAM stands for random access memory.

The term random is used to indicate that the computer does not need to access memory cells in sequence; rather, they can be referenced in any order.


To store data or instructions, main memory or RAM must have electrical power.

When power is shut off, the contents of main memory are lost.

The term volatile is used to indicate that data will be lost when the computer is not powered.◦ Main memory is volatile.


Magnetic and optical disks maintain their contents without power and serves as storage devices.

You can turn the computer off and back on, and the contents of both magnetic and optical disks will be unchanged.◦ Magnetic and optical disk are nonvolatile.


Memory is used for three purposes:◦ It holds instructions of the operating system◦ It holds instructions for application programs such as Excel

or Acrobat.◦ It holds data.

The operating system (OS) is a computer program that controls all of the computer’s resources◦ It manages main memory.◦ It processes key strokes and mouse movements.◦ It sends signals to the display monitor.◦ It reads and writes disk files.◦ It controls the processing of other programs.

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Memory swapping occurs when there is a request to the operating system to store data in memory and the data will not fit because there is not enough free memory to store the requested data.

In this case, the operating system will have to remove something to make space.

Little swapping occurs when:◦ Your computer has a very large main memory.◦ You use only one or a few programs at a time.◦ You use small files.

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You may have a serious problem if:◦ Your computer has a small memory capacity.◦ You need to use many programs or process many large data

files.◦ Your computer has a small memory capacity.

In this latter case, adding more main memory will substantially improve your computer’s performance.

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The CPU reads instructions and data from memory via the data bus.

The maximum speed at which it transfers data is determined by the speed of main memory and the speed and width of the data bus.

A bus that is 16 bits wide can carry 16 bits at a time; one that is 64 bits wide can carry 64 bits at a time.

The wider the bus, the more data it can carry in a given interval of time.

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Because the data transfer rate depends on both the width of the data bus and the speed of main memory, another way to speed up the computer is to obtain faster memory.

Some data are accessed more frequently than other data.◦ Because of this, computer engineers found they could speed up the overall throughput

of the CPU by creating a small amount of very fast memory, called cache memory.◦ The most frequently used data are placed in the cache.◦ Typically, the CPU stores intermediate results and the most frequently used computer

instructions in the cache.

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Each CPU has a clock speed that is measured in cycles per second, or hertz.

A fast modern computer has a clock speed of 3.0 gigahertz (abbreviated GHz), or 3 billion cycles per second.◦ By the time you read this, CPU speeds will be greater.

In general, the faster the clock speed, the faster work will get done.

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A fast CPU and data bus are most useful when processing data that already reside in main memory.◦ Once you have downloaded a large spreadsheet, a fast CPU will rapidly perform

complicated, formula-based what-if analyses.◦ A fast CPU also is useful for processing large graphics files.

Example, manipulating the brightness of the elements of a large picture

If the applications that you or your employees use do not involve millions of calculations or manipulations on data in main memory, then buying the fastest CPU is probably not worthwhile.

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Two key performance factors for main memory are speed and size.

Normally, a particular computer make and model is designed to use a given memory type, and the speed for that type is fixed.◦ There is nothing you can do to increase memory speed.

You can, however, increase the amount of main memory, up to the maximum size of memory that your computer brand and model can hold.◦ In 2005, the maximum amount of memory for new personal computers ranged from 1.5 to 2.0GB.

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If your computer is constantly swapping files, installing more memory will dramatically improve performance.

In truth, memory is cheap and is often the best way to get more performance out of a computer.

Your operating system has tools and utilities that measure main memory utilization and file swapping.

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Magnetic and optical disks provide long-term, nonvolatile data storage. The types and sizes of such storage devices will affect computer performance.

Data are recorded on magnetic disks in concentric circles. ◦ The disks spin inside the disk unit, and as they spin magnetic spots on the disks are read or

written by the read/write head.◦ The time required to read data from a disk depends on two measures:

Rotational delay Seek time

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Rotational delay is the time it takes the data to rotate under the measure, called the rotational delay.◦ It is the seek time it takes the data to rotate under the read/write head.◦ Seek time is the time it takes the read/write head arm to position the head over the correct circle.◦ The faster the disk spins, the shorter the rotational delay.◦ Seek time is determined by the maker and model of the disk device.

Once the read/write head is positioned over the correct spot on the disk, data can flow over the channel to or from main memory.

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Like the data bus, the rate of data transfer depends on the width and speed of the channel.

There are a number of different standards for channel characteristics.◦ As of 2005, a common standard is the ATA-100 (Advance Technology Attachment) standard.◦ The number 100 indicates that the maximum transfer rate is 100MB per second.

You can use a fast disk to compensate, to some extent, for too little memory.

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There are two kinds of optical disks: CDs (compact disks) and DVD (digital versatile disks).◦ Both are made of plastic and coated with a photosensitive material.

Bits are recorded by burning a pit into the photosensitive material using a low-power laser.

The presence of a pit causes light to reflect and signifies a one; the absence of reflection signifies a zero.

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Like magnetic disks, optical disks are nonvolatile; they maintain their contents even when not powered

The practical differences between CDs and DVDs are capacity and speed.◦ A typical CD has a maximum capacity of 700 MB, whereas a DVD disk can store up to 4.7GB.◦ DVD transfer rates about 10 times faster than those for CDs.

CDs and DVDs see their greatest use in the entertainment industry for playing music and videos.

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There are two types of video display monitors: CRTs and LCDs.

CRT monitors use cathode ray tubes, the same devices used in traditional TV screens.

LCD monitors use a different technology called liquid crystal display.◦ With LCD monitors, no tube is required, so they are much slimmer, around 2 inches or so deep.

Both types of monitors display images by illuminating small spots on the screen called pixels.

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The number of pixels displayed depends not only on the size of the monitor, but also on the design of the mechanism that creates the image.

For a CRT monitor, the dot pitch, is the distance between pixels on the screen.◦ The smaller the dot pitch, the sharper and brighter the screen image will be.

For an LCD monitor, the pixel pitch is the distance between pixels on the screen.◦ The smaller the pixel pitch, the sharper and brighter the image will be.

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Each monitor has an optimal resolution, which is the size of the pixel grid (e.g., 1,024 x 768) that will give the best sharpness and clarity.◦ This optimal resolution depends on the size of the screen, the dot or pixel pitch, and other factors.

Each pixel on the monitor is represented in main memory.◦ If the resolution of the monitor is 1,024 x 768, then there will be a table in memory with 1,024 rows and 768 columns.◦ Each cell of this table has a numeric value that represents the color of the pixel that it represents.◦ The amount of memory used for each cell in the pixel grid depends on the number of colors that each pixel is to

display.

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Each pixel on the monitor is represented in main memory (continued)◦ For a black and white image, the cells can consist of a single bit: zero for white and one for black.◦ To represent 16 colors, each pixel is represented by four bits.◦ Today, most monitors use a large palette that necessitates 32 bits for each pixel and allows for 8,589,934,591 colors.

Some computers dedicate a separate memory cache just to the video display.

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Apple Computer, Inc. developed its own operating system for the Macintosh, Mac OS.

Macintosh computers are used primarily by graphic artists and workers in the arts community.

As of 2006, Macintosh computers will be available for both PowerPC and Intel CPUs.

A Macintosh with an Intel processor is able to run both Windows and the MAC OS.

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Unix is an operating system that was developed at Bell Labs in the 1970s.

It has been the workhorse of the scientific and engineering communities since then.

Unix is generally regarded as being more difficult to use than either Windows or the Macintosh.

Many Unix users know and employ an arcane language for manipulating files and data.

In general, Unix is not for the business user.

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Linux is a version of Unix that was developed by the open-source community.

This community is a loosely coupled group of programmers who mostly volunteer their time to contribute code to develop and maintain Linux.

The open source community owns Linux, and there is no fee to use it.

Linux is a popular operating system for Web servers.

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Application software consists of programs that perform a business function.

Some application programs are general purpose, such as Excel or Word.

Other application programs are specific◦QuickBooks, for example, is an application program that provides general ledger, and other accounting functions.

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Sources You can buy computer software several ways:

◦ Off-the-shelf◦ Off-the-shelf with alterations◦ Tailor made

Horizontal-Market Applications Software Horizontal-market application software provides capabilities common across all organizations and industries. Word processor, graphics programs, spreadsheets, and all presentation programs are all horizontal-market application

software.

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Vertical-Market Applications Software Vertical-market application software serves the needs of a specific industry.

Examples of such programs are:◦ Those used by dental offices to schedule appointments and bill patients◦ Those used by auto mechanics to keep track of customer data and customers’ automobile repairs◦ Those used by parts warehouses to track inventory, purchases, and sales

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Custom-Developed Software Sometimes organizations develop custom application software.

They develop such programs themselves or hire a development vendor.

Custom development is difficult and risky.

Every application program needs to be adapted to changing needs and changing technologies .

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Firmware is computer software that is installed into devices like printers, print servers, and various types of communication devices.

The software is coded just like other software, but it is installed into special, read-only memory of the printer or other device.

Users do not need to load firmware into device’s memory.

Firmware can be changed or upgraded, but this is normally a task for IS professionals.

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Computing devices consists of hardware and software.

General-purpose computers can run multiple programs; special-purpose computers, like those in cell phones, run only one program that is fixed in memory.

Hardware can be categorized according to its primary functions: input, processing, output, and storage.

Input hardware includes devices such as keyboards and mice.


Processing hardware includes the CPU and main memory.

Output devices are video displays, printers, and the like.

Storage devices include magnetic and optical disks.

Computers use bits to represent data. A bit, or binary digit, has a value of zero or

one. Bits are used to represent computer

instructions and data.


Four popular operating systems are Windows, Mac, OS, Unix, and Linux.

Computer software consists of the operating system and application software.

Software can be purchased off-the-rack, purchased off-the-rack and then altered, or tailor-made.

Types of software include horizontal, vertical, and custom.

Firmware is program code installed in read-only memory of printers or communications devices.


Antivirus programsApplication softwareATA-100Binary digitB2B (business-to-

business)BusByteCache memoryCD-RCD-ROMCD-RWCRT monitor


Central processing unit (CPU)Clock speedCustom softwareData channelDot pitchDVD-RDVD-ROMDVD-RWFirmwareGeneral-purpose computerGigabyte (GB)Hardware


Horizontal-market application

Input hardwareIntel instruction setKilobyte (K)LCD monitorLicense agreementLinuxMac OSMacro virusMain memoryMegabyte (MB)Memory swapping

MotherboardNonvolatileOEM (original equipment

manufacturer)Off-the-self softwareOpen-source communityOperating system (OS)Optimal resolutionOutput hardwarePatchPayloadPixel


Pixel pitchPower PC instruction setRAM memorySeek timeSoftware piracySpecial function cardsSpecial-purpose computerStorage hardwareTCG/NGSCBTerabyte (TB)Trojan horseUnix

VAR (value-added resellers)

Vertical-market applicationVirusVolatileWindowsWorm


For most problems, in the business world, the difficult and creative acts are generating the questions and formulating a strategy for getting the answers.

Once the questions and strategy are set, the rest is simply legwork.

As a future consumer of information technology and services, you will benefit from being able to ask good questions and effectively obtain answers to them.


It is probably the single most important behavior you can learn.

There are billions of bad questions, and you will be better off if you learn not to ask them.

Questions can be bad in three ways: They can be irrelevant Dead Asked of the wrong source


A dead question is one that leads to nowhere, it provides no insight into the subject. Example–“Is the material on how a computer works going

to be on the test? The answer will help you in school, but it won’t help you

use MIS on the job. Instead ask questions like,

“What is the purpose of the section on how a computer works?”

‘”Why are we studying it?” “How will it help me use MIS in my career?”


Information technology questions fall into three categories: “What is it?” “How can I use it?” “Is it the best choice?”


A virus is a computer program that replicates itself and consumes the computer’s resources.

The program code that causes unwanted activity is called the payload.

There are many different virus types: Trojan horses Macro viruses Worm


Prevention steps are: Find and apply patches to the operating system and to

applications. Never download files, programs, or attachments from

unknown Web sites. Do not open attachments to emails from strangers. Do not open unexpected attachments to emails, even

from known sources. Do not rely on file extensions. Run a retroactive antivirus program at regular intervals,

at least once per week.


“Frankly, I think there’s a conspiracy between hardware and software vendors”. “They both want to sell new products, so the hardware

people come up with these incredibly fast and huge computers”.

“Then, given all that power, the software types develop monster products bloated with features and functions that nobody uses”.

“It would take me months to learn all the features in Word, not only to find out that I don’t need those features”.

“In my version of Word, there are 19 toolbars to select, plus one more to customize my own toolbar”.


“Frankly, I think there’s a conspiracy between hardware and software vendors” (continued) “I write all the time, and I have two selected: Standard and

Formatting”.

“Because we live in a connected world, they don’t have to get all of us to use those 19 toolbars, just one of us”. “Bridgette likes to use the redlining features, and she likes

me to use them when I change draft contracts she sends me”.

“So, If I want to work on her documents, I have to turn on the Reviewing toolbar”.


“Viruses are one of their best ploys. They say you can better buy the latest and greatest products in software, and then apply all the patches that follow so that you’ll be protected from the latest zinger from the computer bad guys”. “If vendors had built the products correctly the first time,

then there would be no holes for the baddies to find, would there?”

“One of these days, users are going to rise up and say, That’s enough. I don’t need any more. I’ll stay with what I have, thanks you very much.” “In fact, maybe that’s happening right now”


Every commercial software program, whether an operating system or an application, is sold under the restrictions of a license agreement that stipulates how the program can be used.

Software piracy occurs when a programs are used in violation of the license agreement.

Piracy occurs on a large scale when a company illegally copies a program and sells it on the black market.


But piracy also occurs on a small scale when one user allows another user to load the program on her computer in violation of the license agreement.

Over the years, vendors have applied many different techniques to prevent software piracy.

The most effective strategies involve a combination of hardware and program identify.

Today, Microsoft, Intel, and other companies have been working together on a project called TCG/NGSCB.


No products yet implement this work, but product designs are underway.

According to the TCG standard, future computers will include a hardware component that emits passwords and other security data that uniquely identify that particular computer. Because these identifiers are created by the hardware,

they cannot be hacked without running the hardware. The bottom line is that software companies will be able

to license programs to a particular computer.


Once the TCG/NGSCB has been implemented, it can be used to enforce not only program licenses, but content licenses as well. Entertainment companies and other content vendors will

be able to license music, video, and similar content to a particular computer.

With the TCG/NGSCB components in place, no other computer will be able to play copies of that music, video, or file.


Microsoft and other software vendors will license software to a particular computer, possibly for a particular time period. The license will automatically expire at the end of that

period. Any attempt to run unlicensed software will fail and could

result in the sending of a report to the vendor that such an attempt was made.

Software vendors can make the files unusable after the licenses expire.


Governments can ensure that sensitive government documents are readable only on certain machines.

The industry groups justify this program as providing a “secure computing environment” and attempt to spin this initiative as something that will benefit the consumer.

Hundreds of independent observers disagree with these stated objectives and believe the objective is to prevent unauthorized copying of software and files.


Technology change is a fact, and the only appropriate question is, “What am I going to do about it?” One strategy you can take is to bury your head in the sand:

“Look, I’m not a technology person. I’ll leave it to the pros. As long as I can send email and use the Internet, I’m happy.”

This strategy is fine, as far as it goes, and many business people use it. However, it won’t give you a competitive advantage over anyone, and it will give someone else a competitive advantage over you.

What about your department though? If the expert says, “Every computer needs a 120GB disk,” are you going to nod your head and say, “Great. Sell them to me!” Or, are you going to know enough to realize that’s a big disk and ask why everyone needs such a large amount of storage?


At the other end of the spectrum, are those who are not only knowledgeable in their field, but also enjoy information technology. These people are sprinting along the technology conveyor

belt; they will never end up in the techno-trash, and they will use their knowledge of IT to gain competitive advantage throughout their careers.

Many business professionals are in between these extremes.


There are a couple of strategies: Don’t allow yourself to ignore technology. Take a seminar or pay attention to professional events that

combine your specialty with technology. Get involved in as a user in your organization. Later in your career, become a member of the business

practice technology committee, or whatever they call it at your organization.

Documents

David Kroenke Hardware and Software Chapter 3 © 2007 Prentice Hall, Inc. 1