An Introduction to Computers · An Introduction to Computers © 2003 Lawrenceville Press An Introduction to Computers 1 Mechanical Devices..... 1 2 Electro-Mechanical Devices .....

An Introduction to Computers © 2003 Lawrenceville Press

An Introduction to Computers

1 Mechanical Devices ....................................................... 12 Electro-Mechanical Devices ......................................... 33 First Generation Computers ........................................ 44 The Stored Program Computer .................................. 55 Second Generation Computers ................................... 66 Programming Languages ............................................. 67 Third Generation Computers ...................................... 78 Mainframes ...................................................................... 79 Fourth Generation Computers .................................... 810 Interpreted and Object-Oriented

Programming Languages ............................................. 811 The Desktop PC .............................................................. 912 Mobile Computing ....................................................... 1013 Number Systems .......................................................... 1114 Storing Data in Memory ............................................. 1215 Networks ....................................................................... 1316 Intranet, Extranet, and Internet ................................ 1617 Accessing the Internet ................................................. 1618 Telecommunications .................................................... 1619 Internet Services ........................................................... 1720 Internet Privacy Issues ................................................ 1721 Acceptable Use Policy ................................................. 2022 The Social and Ethical Implications

of Computers ................................................................ 2023 Protecting Computer Software and Data ............... 2124 IT Careers ....................................................................... 2225 The Ethical Responsibilities

of an IT Professional .................................................... 25Chapter Summary ........................................................ 26Vocabulary ..................................................................... 29Review Questions ........................................................ 33Exercises ......................................................................... 36Index ............................................................................... 39

An Introduction to Computers © 2003 Lawrenceville Press

ExpectationsAfter completing this chapter you will be able to:

1. Discuss the history of computers.

2. Discuss the evolution of programming languages.

3. Describe the internal and external components of a desktop PC.

4. Understand the binary number system.

5. Discuss mobile computing.

6. Describe the benefits of using a network.

7. Define network architecture and identify the differences innetwork topologies.

8. Apply netiquette rules when using a network and understand theneed for an Internet Use Agreement.

9. Distinguish between an intranet, extranet and the Internet.

10. Summarize how the Internet works and explain how to access theInternet.

11. Describe telecommunications options.

12. Identify various Internet services.

13. Analyze Internet privacy issues and understand the purpose of anAcceptable Use Policy.

14. List ways computer software and data can be protected.

15. Discuss IT careers.

16. Analyze the ethical responsibilities of an IT professional.

1An Introduction to Computers © 2003 Lawrenceville Press

This chapter discusses the history of computers, current computingtechnologies, computer networks, and issues related to computers, in-cluding privacy, computer use agreements, protecting data, and careers.

1 Mechanical DevicesOne of the earliest mechanical calculating devices was the Pascaline,

invented in 1642 by the French philosopher and mathematician BlaisePascal. The Pascaline was a complicated set of gears that operated simi-larly to a clock. It was designed to only perform addition. Unfortunately,due to manufacturing problems, Pascal never got the device to workproperly.

The Pascaline was a mechanical calculating deviceinvented by Blaise Pascal in 1642

Later in the 17th century Gottfried Wilhelm von Leibniz, a famousmathematician, invented a device that was supposed to be able to addand subtract, as well as multiply, divide, and calculate square roots.His device, the Stepped Reckoner, included a cylindrical wheel called theLeibniz wheel and a moveable carriage that was used to enter the numberof digits in the multiplicand. However, because of mechanicallyunreliable parts, the device tended to jam and malfunction.

The Stepped Reckoner was another early attempt atcreating a mechanical calculating device

Blaise Pascal1623 – 1662

Gottfried Wilhelmvon Leibniz1646 – 1716

Stepped Reckoner

Pascaline

2 An Introduction to Computers © 2003 Lawrenceville Press

In 1822 Charles Babbage began work on the Difference Engine, whichwas intended to calculate numbers to the 20th place and then print themat 44 digits per minute. The original purpose of this machine was toproduce tables of numbers that would be used by ships’ navigators. Atthe time, navigation tables were often highly inaccurate due to calcula-tion errors and a number of ships were known to have been lost at seabecause of these errors. Although never built, the ideas for the Differ-ence Engine led to the design of Babbage’s Analytical Engine.

The Analytical Engine, designed around 1833, was supposed to performa variety of calculations by following a set of instructions, or program,stored on punched cards. During processing, the Analytical Engine wasplanned to store information in a memory unit that would allow it tomake decisions and then carry out instructions based on those decisions.For example, when comparing two numbers, it could be programmedto determine which was larger and then follow an appropriate set ofinstructions. The Analytical Engine was also never built, but its designserved as a model for the modern computer.

Babbage’s Analytical Engine was designed as acalculating machine that used punched cards

to store information

Babbage’s chief collaborator on the Analytical Engine was Ada Byron,Countess of Lovelace, the daughter of Lord Byron. Interested in math-ematics, Lady Byron was a sponsor of the Analytical Engine and one ofthe first people to realize its power and significance. She also wrote ofits achievements in order to gain support for it. Ada Byron is often calledthe first programmer because she wrote a program based on the designof the Analytical Engine.

Babbage had hoped that the Analytical Engine would be able to think.Ada Byron, however, said that the Engine could never “originateanything,” meaning that she did not believe that a machine, no matterhow powerful, could think. To this day her statement about computingmachines remains true.

The History ofPunched Cards

Punched cards originally pro-vided instructions for weavinglooms. In 1810 Joseph Jac-quard, a French weaver,placed punched cards in hislooms so that as the cardspassed through the loom in se-quence, needles passedthrough the holes and pickedup threads of the correct coloror texture.

Charles Babbage1792 – 1871

Ada Byron1815 – 1852

Difference Engine

Analytical Engine


2 Electro-Mechanical DevicesBy the end of the 19th century, U.S. Census officials were concerned

about the time it took to tabulate the continuously increasing numberof Americans. This counting was done every 10 years, as required bythe Constitution. However, the Census of 1880 took nine years to com-pile which made the figures out of date by the time they were published.

In response to a contest sponsored by the U.S. Census Bureau, HermanHollerith invented a tabulating machine that used electricity rather thanmechanical gears. Holes representing information to be tabulated werepunched in cards, with the location of each hole representing a specificpiece of information (male, female, age, etc.). The cards were theninserted into the machine and metal pins used to open and close electricalcircuits. If a circuit was closed, a counter was increased by one.

Herman Hollerith’s tabulating machine, invented for theCensus of 1890, used electricity instead of gears to

perform calculations

Hollerith’s machine was immensely successful. The general count ofthe population, then 63 million, took only six weeks to compile. Althoughthe full statistical analysis took seven years, it was still an improvementover the nine years it took to compile the previous census.

In 1944, the Mark I was completed by a team from International Busi-ness Machines (IBM) and Harvard University under the leadership ofHoward Aiken. The Mark I used mechanical telephone relay switchesto store information and accepted data on punched cards. Because itcould not make decisions about the data it processed, the Mark I wasnot a computer but instead a highly sophisticated calculator. Neverthe-less, it was impressive in size, measuring over 51 feet in length andweighing 5 tons. It also had over 750,000 parts, many of them movingmechanical parts which made the Mark I not only huge but unreliable.

The Mark 1 was over 51 feet long and weighed over 5 tons

Herman Hollerith1860 – 1929

Based on the success of histabulating machine, HermanHollerith started the Tabulat-ing Machine Company in1896. In 1924, the companywas taken over by Interna-tional Business Machines(IBM).

Howard Aiken1900 – 1973

Hollerith’s tabulating machine

Mark I


3 First Generation ComputersThe first electronic computer was built between 1939 and 1942 at Iowa

State University by John Atanasoff, a math and physics professor, andClifford Berry, a graduate student. The Atanasoff-Berry Computer (ABC)used the binary number system of 1s and 0s that is still used in comput-ers today. It contained hundreds of vacuum tubes and stored numbersfor calculations by electronically burning holes in sheets of paper. Theoutput of calculations was displayed on an odometer type of device.

The Atanasoff-Berry Computer used the binary numbersystem used in computers today

The patent application for the ABC was not handled properly, and itwas not until almost 50 years later that Atanasoff received full creditfor his invention. In 1990, he was awarded the Presidential Medal ofTechnology for his pioneering work. A working replica of the ABC wasunveiled at the Smithsonian in Washington, D.C. on October 9, 1997.

In June 1943, John Mauchly and J. Presper Eckert began work on theENIAC (Electronic Numerical Integration and Calculator). It wasoriginally a secret military project which began during World War II tocalculate the trajectory of artillery shells. Built at the University of Penn-sylvania, it was not finished until 1946, after the war had ended. Butthe great effort put into the ENIAC was not wasted. In one of its firstdemonstrations, ENIAC was given a problem that would have taken ateam of mathematicians three days to solve. It solved the problem intwenty seconds.

The ENIAC was originally a secret military project

John Atanasoff1903 – 1995

Clifford Berry1918 – 1963

John Mauchly1907 – 1980

J. Presper Eckert1919 – 1995

Atanasoff-Berry Computer

ENIAC


The ENIAC weighed 30 tons and occupied 1500 square feet, the samearea taken up by the average three bedroom house. It contained over17,000 vacuum tubes, which consumed huge amounts of electricity andproduced a tremendous amount of heat requiring special fans to coolthe room.

The ABC and the ENIAC are first generation computers because theymark the beginning of the computer era. A computer is an electronicmachine that accepts data, processes it according to instructions, andprovides the results as new data. A computer can also make simpledecisions and comparisons.

4 The Stored Program ComputerThe ABC and ENIAC required wire pulling, replugging, and switch

flipping to change their instructions. A breakthrough in the architec-tural design of first generation computers came as a result of separatepublications by Alan Turing and John von Neumann, both mathemati-cians with the idea of the stored program.

In the late 30s and 40s, Alan Turing developed the idea of a “universalmachine.” He envisioned a computer that could perform many differenttasks by simply changing a program rather than by changing electroniccomponents. A program is a sequence of instructions written in a codethat the computer understands.

In 1945, John von Neumann presented his idea of the stored programconcept. The stored program computer would store computerinstructions in a CPU (Central Processing Unit). The CPU consisted ofdifferent elements used to control all the functions of the computerelectronically so that it would not be necessary to flip switches or pullwires to change instructions.

Together with Mauchly and Eckert, von Neumann designed and builtthe EDVAC (Electronic Discrete Variable Automatic Computer) and theEDSAC (Electronic Delay Storage Automatic Computer). Thesecomputers were designed to solve many different problems by simplyentering new instructions that were stored on paper tape. Theinstructions were in machine language, which consists of 0s and 1s torepresent the status of a switch (0 for off and 1 for on).

The third computer to employ the stored program concept was theUNIVAC (UNIVersal Automatic Computer) built by Mauchly andEckert. With the UNIVAC came the first computer language called C-10, which was developed by Betty Holberton. Holberton also designedthe first computer keyboard and numeric keypad in an effort to makethe computer more user-friendly. The first UNIVAC was sold to theU.S. Census Bureau in 1951.

These first generation computers continued to use many vacuum tubeswhich made them large and expensive. They were so expensive topurchase and run that only the largest corporations and the U.S.government could afford them. Their ability to perform up to 1,000calculations per second, however, made them popular.

Alan Turing1912 – 1954

Johnvon Neumann1903 – 1957

CPU

EDVAC

UNIVAC

machine language

program

EDSAC

Francis “Betty”Holberton

1917 – 2001

C-10

ColossusBuilt two years before theENIAC, the Colossus was aspecial-purpose computerdesigned by Tommy Flowers,an engineer at the Post OfficeResearch Station in England.The Colossus was designed tobreak codes during WorldWar II. Its effectiveness playeda major role in ending thewar.


5 Second Generation ComputersIn 1947, William Shockley, John Bardeen, and Walter Brittain of Bell

Laboratories invented the transistor. A transistor is a semiconductordevice that could replace a vacuum tube. Transistors were much smallerthan vacuum tubes, less expensive, and allowed computer to processup to 10,000 calculations per second:

Transistors made computers smaller, less expensive,and more reliable than those with vacuum tubes

In the early 1960s, IBM introduced the first medium-sized computernamed the Model 650. It was expensive, but much smaller than first gen-eration computers and still capable of handling the flood of paperworkproduced by many government agencies and businesses. Such organi-zations provided a ready market for the 650, making it popular in spiteof its cost.

Second generation computers also saw a change in the way data wasstored. Punched cards were replaced by magnetic tape and high speedreel-to-reel tape machines. Using magnetic tape gave computers the abil-ity to read (access) and write (store) data quickly and reliably.

6 Programming LanguagesMachine language is comprised of just 1s and 0s and is the only language

that a computer understands. It is called a low-level computer languagebecause machine language programs are written to directly address thecomputer’s hardware. Writing a program in machine language iscomplex and tedious because the sets of numbers that represent eachcommand are difficult to memorize and recognize.

Programming became easier when another low-level language calledassembly language was developed with names to represent machinelanguage instructions. In order for the computer to understand anassembly language program, it must be translated into machine languagewith another program called an assembler.

Second generation computers had more capabilities than firstgeneration computers and were more widely used by businesses. Thisled to the need for high-level programming languages that had English-like instructions and were easier to use than machine language andassembly language. In 1957, John Backus and a team of researcherscompleted Fortran, a high-level programming language with intuitivecommands such as READ and WRITE.

High-level languages are translated into assembly language with aprogram called a compiler. The first compiler, A-0, was created in 1951by Grace Murray Hopper, a Commodore in the Navy at the time.

transistor

Model 650

read, write

John Bardeen, WilliamShockley, and Walter

Brittain

machine language

assembly language

high-level language

compilerA-0

Fortran

low-level language

assembler


COBOL (COmmon Business Oriented Language), developed in 1959by Grace Murray Hopper and the United States Department of Defense(DOD), provided a common language for use on all computers and waswidely used for business applications. In the late 1970s, the DOD alsodeveloped Ada, named after the first programmer, Ada Byron. Ada is ahigh-level programming language that supports real-time applications.Systems that rely on real-time processing, such as those used in thebanking industry, are often programmed in Ada.

Also developed in the 1970s was the C programming language. C wascreated by Dennis Ritchie at Bell Laboratories and is used to write avariety of applications. It requires less memory than other languagesand can be used to write very efficient code.

7 Third Generation ComputersThe use of integrated circuits (ICs) began the third generation of

computers. In 1961, Jack Kilby and Robert Noyce, workingindependently, developed the IC, also called a chip. Hundreds oftransistors, as well as other electronic components and wiring could behoused within a single IC, which allowed computers to processinformation at a rate of millions of calculations per second.

ICs are created from silicon wafers which are then etched with intri-cate circuits and then coated with a metallic oxide to allow the circuitsto conduct electricity. The silicon wafers are housed in special plasticcases that have metal pins. The pins allow the ICs to be plugged intocircuit boards that have wiring printed on them.

A typical chip is about 1 cm wide by 2.5 cm long

In 1964, the IBM System 360 was one of the first computers to useintegrated circuits and was so popular with businesses that IBM haddifficulty keeping up with the demand. Computers had come down insize and price to such a point that smaller organizations such as univer-sities and hospitals could now afford them.

8 MainframesA mainframe is a large computer system that supports multi-user

applications. Large corporations, banks, government agencies, anduniversities use mainframes for tasks such as calculating payrolls,keeping records, handling reservations, and storing student data—tasksthat require the storage and processing of huge amounts of information.The IBM System 360 was one of the first mainframes available.

Mainframe computers usually require their own room

Jack S. Kilby1923 –

Kilby, working for TexasInstruments, developed thefirst integrated circuit. He usedthis new technology to createthe first electronic handheldcalculator.

Grace Murray Hopper1906 – 1992

Rear Admiral Dr. GraceMurray Hopper used the term“debug” when removing amoth that had flown into thecircuitry of the Mark II.

Robert Noyce1927 – 1990

Noyce developed the inte-grated circuit while working atFairchild Semiconductor. In1968, he formed the companythat is now Intel Corporation.


Most people using mainframes communicate with them usingterminals. A terminal consists of a keyboard for data input, and a moni-tor for viewing output. The terminal is connected to the mainframe,which may be located on a different floor or in a building a few blocksaway. Some mainframes have hundreds of terminals attached.

9 Fourth Generation ComputersIn 1970, Marcian Hoff, an engineer at Intel Corporation, invented the

microprocessor, an entire CPU on a single chip. The replacement of sev-eral larger components by one microprocessor made possible the fourthgeneration of computers.

The small microprocessor made it possible to build a computer calleda microcomputer, which was small enough to fit on a desktop. The firstof these was the Altair built in 1975. In 1976, Stephen Wozniak and StevenJobs designed and built the first Apple computer. The Apple Macintoshset new standards for ease of computer use with its graphical userinterface. In 1981, IBM introduced the IBM–PC. The computer was aninstant success because of the availability of spreadsheet, accounting,and word processor software. Desktop computers are referred to aseither PCs or Macs.

Advances in technology made personal computers inexpensive andtherefore available to many people. Because of these advances almostanyone could own a machine that had more computing power and wasfaster and more reliable than either the ENIAC or UNIVAC. As a com-parison, if the cost of a sports car had dropped as quickly as that of acomputer, a new Porsche would now cost about one dollar.

10 Interpreted and Object-OrientedProgramming Languages

In the 1960s, John Kemeny and Thomas Kurtz developed BASIC atDartmouth University. BASIC (Beginner’s All-Purpose SymbolicInstruction Code) uses an interpreter, rather than a compiler, to translatecode into instructions that run on a computer. An interpreter executescode without completely converting a program to machine language.BASIC has been used extensively to teach programming because codecan be tested as it is written.

In the 1980s, object-oriented programming (OOP) evolved out of the needto better develop complex programs in a systematic, organized approach.The OOP approach allows programmers to create modules that can beused over and over again in a variety of programs. These modulescontain code called classes, which group related data and actions.Properly designed classes encapsulate data to hide the implementationdetails, are versatile enough to be extended through inheritance, andgive the programmer options through polymorphism. Object-orientedlanguages use a compiler to translate code and include Visual Basic .NET,C++, C#, and Java.

microprocessor

Marcian Hoff1937 –

Stephen Wozniak1950 –

Steve Jobs1955 –

4GLsFourth-generation languages(4GLs) are more high levelthan high-level languages.4GL programs are closer tohuman language than otherprogramming languages. Pro-grams that access databasesare usually written in a 4GL.


11 The Desktop PCThe physical components of the desktop PC, such as the monitor and

base unit, are called hardware:

• The PC accepts data from input devices. Examples of inputdevices include the keyboard, mouse, CD-RW/DVD drive, anddiskette drive.

• A PC becomes much more versatile when other input andoutput devices such as printers and scanners are added. Suchdevices are sometimes called peripheral devices. A scanner is aninput device that uses a laser to create a digital image fromartwork such as photos and drawings. The digitized image canthen be incorporated into a document.

• Output devices display or store processed data. Monitors andprinters are display output devices. The CD-RW and diskettedrives are used for storing data. Other storage devices includeZip drive, removable hard disk drive, and tape drive.

The base unit contains many storage devices such as a CD-RW/DVDdrive, a diskette drive, and a hard disk drive. The CD-RW/DVD anddiskette drives are accessible from outside the base unit, and the harddisk is completely contained inside the base unit.

The base unit also contains the motherboard, which is the main circuitboard that contains the components:

• Expansion boards are circuit boards that connect to themotherboard and contain components for a particular purpose.The circuit board for adding a computer to a network is anexpansion board. A video adaptor expansion board is requiredfor using a monitor.

• The CPU (Central Processing Unit) processes data and controlsthe flow of data between the computer’s other units. Withinthe CPU is the ALU (Arithmetic Logic Unit), which can performarithmetic and logic operations. It can also make comparisons,which is the basis of the computer’s decision-making power.The ALU is so fast that the time needed to carry out a singleaddition is measured in nanoseconds (billionths of a second). Thespeed at which a CPU can execute instructions is determinedby the computer’s clock rate. The clock rate is measured inmegahertz (million of cycles per second) or gigahertz (billion ofcycles per second) and can range from 450 MHz to over 3 GHz.

nanoseconds

clock rate

PrintersA laser printer uses a laser andtoner to generate charactersand graphics on paper. An inkjet printer uses an ink cartridgeto place very small dots of inkonto paper to createcharacters and graphics.

CPU

megahertz, gigahertz

ALU

input devices

peripheral devices

output devices

expansion board

storage devices

base unit

motherboard


• A computer’s memory is in the form of ICs that store dataelectronically. ROM (Read Only Memory) contains the mostbasic operating instructions for the computer. The data in ROMis a permanent part of the computer and cannot be changed.RAM (Random Access Memory) is memory where data andinstructions are stored temporarily. Data stored in RAM canbe written to any type of storage media, such as a floppy diskette,a hard disk, a Zip disk, or a CD-RW.

• SRAM (Static Random Access Memory) is high-speed memoryreferred to as cache (pronounced “cash”). This memory is usedto store frequently used data so that it can be quickly retrievedby an application.

• A bus is a set of circuits that connect the CPU to other com-ponents. The data bus transfers data between the CPU, memory,and other hardware devices on the motherboard. The addressbus carries memory addresses that indicate where the data islocated and where the data should go. A control bus carriescontrol signals.

All data flows through the CPU:

Input Memory Output

CPU

Because one of the tasks of the CPU is to control the order in whichtasks are completed, it is often referred to as the “brain” of the computer.However, this comparison with the human brain has an important flaw.The CPU only executes tasks according to the instructions it has beengiven; it cannot think for itself.

A PC also contains different programs, or software. Operating systemsoftware is run automatically when the computer is turned on and enablesthe user to communicate with the computer with input devices such asthe mouse and keyboard. Applications software is written by programmersto perform a specific task, such as a word processor.

12 Mobile ComputingImproved technology has allowed the miniaturization of computer

components and special long-lasting batteries. Computers now come inmany shapes, sizes, and with many levels of features. Among thesecomputers are notebooks, tablets, handhelds, and wearables. Becauseof their portability, these types of computer are considered mobilecomputing devices.

A notebook PC is about the size of a textbook and can replace a desk-top PC because its CPU, memory, and hard disk space is comparable tothat of a typical desktop PC. The monitor size of a notebook can rangefrom 15" to 17", making it easy to use for long periods of time. Manytypes of input and output devices can be used with a notebook.

operating system software

applications software

storage media

cacheSRAM

busdata bus

control bus

address bus

software

RAM

notebook PC

memory

CPUsIntel and AMD are the twobiggest manufacturers ofCPUs. The Intel Pentium 4(P4) CPU has a clock rate of3.06 GHz. AMD produces theAthlon XP CPU with a clockrate of 2.16 GHz. These CPUscontain more than 40 milliontransistors on a single chip.

BluetoothBluetooth is a wirelesstechnology used to allowmobile computing devices tocommunicate.

ROM


The design of the tablet PC is based on a pad of paper and a pencil.Users simply “write” on a screen with a device called a stylus that isshaped like a thin pencil. The screen size ranges from 10" to 12" and canbe held in the user’s arm as a tablet would be. Table PCs fall into twodivisions, slate or convertible. A slate tablet uses just the stylus for in-put, and the convertible also usually includes a keyboard for input. TablePCs also include software for handwriting recognition. Although, theprocessor speed and memory capacity of tablet PCs is comparable tothat of a notebook PC, tablets have few options for input and output.

Handheld PCs are quickly becoming ubiquitous because of their size,price, and capabilities. Handhelds, also called PDAs, are palm-sized andcontain applications for storing contact information, schedules, lists, andgames. Handhelds come with a stylus for input and have a screen thatis several inches vertically. Many types of application software have beenwritten for handhelds, including spreadsheets and simple word pro-cessors. Some handhelds recognize handwriting, include a cellularphone, and provide Internet access.

Wearable computers vary greatly in size and application. MP3 playershave been incorporated into clothing, and one type of wearable computerincludes voice recognition. Wearable computers are also in the form ofgoggles, which incorporate a monitor, digital camera, ear bud, andmicrophone. Wrist-top computers are worn like a traditional wrist watchand work as a pager, provide Internet access, and contain other featuresusually found in a handheld PC.

One issue involved with using so many types of PCs is cross-platformconnectivity, which is the ability for one type of PC to link to and sharedata with a different type of PC. Notebook and desktop PCs typicallyhave good cross-platform connectivity because their file formats can beused on either computer. Tablets and handhelds use a different OS andgenerate different file formats, requiring special hardware and softwareto use their files on a desktop or notebook PC. Wearable computers typi-cally have a cable that allow a connection to other types of PCs, butspecial software must be used to communicate between the devices.

13 Number SystemsThe electrical circuits on an IC have one of two states, off or on. There-

fore, the binary number system (base 2), which uses only two digits (0and 1), was adopted for use in computers. To represent numbers andletters, a code was developed with eight binary digits grouped togetherto represent a single number or letter. Each 0 or 1 in the binary code iscalled a bit (BInary digiT) and an 8-bit unit is called a byte.

Our most familiar number system is the decimal, or base 10, system.It uses ten digits: 0 through 9. Each place represents a power of ten,with the first place to the left of the decimal point representing 100, thenext place representing 101, the next 102, and so on (remember that anynumber raised to the zero power is 1). In the decimal number 485, the 4represents 4×102, the 8 represents 8×101, and the 5 represents 5×100. Thenumber 485 represents the sum 4×100 + 8×10 + 5×1 (400 + 80 + 5) asshown on the next page:

slateconvertible

handheld PCPDAs

wearable computer

binary number system

bit, byte

base 10

tablet PC

cross-platform connectivity


Decimal Base 10 Equivalent485 4×102 + 8×101 + 5×100 = 400 + 80 + 5

The binary, or base 2, system works identically except that each placerepresents a power of two instead of a power of ten. For example, thebinary number 101 represents the sum 1×22 + 0×21 + 1×20 or 5 in baseten. Some decimal numbers and their binary equivalents are:

Decimal Binary Base 2 Equivalent0 0 = 0×21 + 0×20 = 0×2 + 0×1 = 0 + 01 1 = 0×21 + 1×20 = 0×2 + 1×1 = 0 + 12 10 = 1×21 + 0×20 = 1×2 + 0×1 = 2 + 03 11 = 1×21 + 1×20 = 1×2 + 1×1 = 2 + 14 100 = 1×22 + 0×21 + 0×20 = 1×4 + 0×2 + 0×1 = 4 + 0 + 0

The hexadecimal system is used to represent groups of four binarydigits. The hexadecimal, or base 16, system is based on 16 digits: 0 through9, and the letters A through F representing 10 through 15 respectively.Each place represents a power of sixteen. For example, the hexadecimalnumber 1F represents the sum 1×161 + 15×160. Some decimal numbersand their hexadecimal equivalents are shown below:

Decimal Binary Hexadecimal Base 16 Equivalent0 0000 0000 0 = 0×160 = 0×1 = 010 0000 1010 A = 10×160 = 10×1 = 1025 0001 1001 19 = 1×161 + 9×160 = 1×16 + 9×1 = 16 + 930 0001 1110 1E = 1×161 + 14×160 = 1×16 + 14×1 = 16 + 14

For clarity, a non-base 10 number should have the base subscriptedafter the number. For example, to show the difference between 100 inbase 10 and 100 in base 2 (which represents 4), the base 2 number shouldbe written as 1002.

Every letter of an alphabet (Latin, Japanese, Cherokee, and so on) andsymbols of every culture (=, @, ½, and so on) have been given a repre-sentation in a digital code called Unicode. Unicode uses a set of sixteen1s and 0s to form a 16-bit binary code for each symbol. For example, theuppercase letter V is Unicode 00000000 01010110, which can be thoughtof as the base 10 number 86 (8610). Lowercase v has a separate code of00000000 01110110, or 11810.

14 Storing Data in MemoryComputer memory, file sizes, and storage device capacities are

measured in bytes. For example, a computer might have 640MB of RAM.In computers and electronics MB stands for megabytes where megarepresents 220 or 1,048,576 bytes and GB stands for gigabytes, which is230 or 1,073,741,820 bytes. Simple files, such as a text document, can bemeasured kilobytes, for example 64K. The K comes from the word kiloand represents 210 or 1,024. Therefore, a 64K file uses 65,536 bytes (64 ×210 ) of storage.

Data stored in memory is referred to by an address. An address is aunique binary representation of a location in memory. Therefore, datacan be stored, accessed, and retrieved from memory by its address. For

hexadecimal

Unicode

megabyte, MBgigabyte, GB

kilobyte, K

memory address

base 2


data to be addressable in memory, it must usually be at least one bytein length. For example, to store JIM in memory each character is con-verted to Unicode and stored in two bytes of memory with each memorylocation designated by its address:

Because JIM is a character string, it will probably be stored in adjacentmemory addresses.

Bits grouped in units of 16 to 64 (2 to 8 bytes) are called words. Datastored in a word is also located by an address. The size of a worddepends on the computer system.

The binary representation of an integer number is usually stored infour bytes of memory. Because an integer is stored in four bytes, therange of integers that can be stored is –2,147,483,648 to 2,147,483,647.An overflow error occurs when the number of bits that are needed torepresent the integer is greater than the size of four bytes.

Real numbers, also called floating point numbers, are numbers that con-tain decimal points. The binary representation of a real number is usually4 to 8 bytes of memory. The binary number 111.10 is equivalent to thereal decimal number 7.5 and is stored in memory as the binary number0.11110×23. In this form, the bits that represent the mantissa (fractionalpart) are stored in one section of a word and the exponent, in thisexample 3 (112), is stored in another section of the word:

The overflow problem discussed for integers can also occur in realnumbers if the part of the word storing the exponent is not large enough.A roundoff error occurs when there are not enough bits to hold themantissa.

15 NetworksA network is a combination of hardware and software that allows

computers to exchange data and share software and devices, such asprinters. Networks are widely used by businesses, universities, and otherorganizations because a network:

• allows users to reliably share and exchange data in a faster,more efficient way

• can reduce costs by sharing devices such as printers

• offers security options including password protection to restrictaccess to certain files

• simplifies file management through centralized software up-dates and file backups

• provides e-mail for network users

word

overflow error

floating point numbers

roundoff error

PronunciationLAN, WAN, MAN, and HANall rhyme with Jan.

MAN and HANA MAN (Metropolitan AreaNetwork) and a HAN (HomeArea Network) are networktechnologies classified by thesize of a network. A MAN is ahigh-speed network that canspan a distance of up to 75km. A HAN is used to connectpersonal devices within thehome.


Networks are classified by their size, architecture, and topology. Acommon size classifications is LAN (Local-Area Network), which is anetwork used to connect devices within a small area such as a buildingor a campus. A WAN (Wide-Area Network) is used to connect devicesover large geographical distances. A WAN can be one widespreadnetwork or it can be a number of LANs linked together.

The computers and other devices in a LAN each contain an expan-sion card called a network interface card:

network interface card

A cable plugs into the network interface card to connect one device toanother to form a LAN.

Along with the physical, or hardware, aspects of setting up a network,there is also the software aspect. A network operating system is softwarethat allow users and devices to communicate over the network. Theoperating system installed must be capable of supporting networkingfunctions, such as security access features and support for multiple users.Operating systems capable of network functions are available for Linux,Windows, Unix, and Mac. The network architecture, discussed next,must also be considered when choosing a network OS.

Network architecture includes the type of computers on the networkand determines how network resources are handled. Two commonmodels are peer-to-peer and client/server. In a peer-to-peer network, eachcomputer on the network is considered equal in terms of responsibilitiesand resource sharing. A client/server network consists of a group ofcomputers, called clients, connected to a server. A server is a computerwith more RAM, a larger hard disk, and sometimes multiple CPUs thatis used to manage network functions.

Physical topology refers to the arrangement of the nodes on a network.A node is a location on the network with a device capable of processinginformation, such as a computer or a printer. There are three commonphysical topologies:

• The bus topology is a physical LAN topology that uses a singlecentral cable, called the bus or backbone to attach each nodedirectly:

LAN using a bus topology

bus topology

client/server

peer-to-peer

network architecture

nodetopology

bus

network OS

server computer

Transmission MediaComputers must be connectedin order to transmit data be-tween the nodes. The cablingused for the connection iscalled the transmission media,which can include twisted-pair wiring, coaxial cable, andfiber optic cable.

The amount of data and thespeed at which data can travelover a media is called band-width, which is measured inbits per second (bps). Eachtransmission media has a spe-cific length or range restric-tion, data transmission rate,and cost.


• In a star topology, each node is attached to a hub, which is adevice that joins communication lines at a central location onthe network:

LAN using a star topology

• In a ring topology, each node is connected to form a closed loop.A LAN with a ring topology can usually cover a greater dis-tance than a bus or star topology:

LAN using a ring topology

Another type of topology is logical topology, which refers to the waydata is passed between the nodes on a network. A LAN’s logical topologyis not always the same as its physical topology.

Network users are given a user name and password to log on to anetwork through a computer connected to the network. Users are alsoassigned a level of access to maintain security. Network users shouldfollow a certain etiquette referred to as netiquette:

• Do not attempt to access the account of another user withoutauthorization.

• Do not share your password, and change it periodically.

• Use appropriate subject matter and language, and be consider-ate of other people’s beliefs and opinions.

star topology, hub

ring topology

Baseband andBroadband TechnologyMost LANs use basebandtechnology which means thetransmission media carriesone signal at a time. Broad-band technology allows fordata transmission of more thanone signal at a time and isfound in WANs.

logical topology

EthernetA protocol is a standard. TheEthernet LAN protocol wasdeveloped by Bob Metcalfe in1976. Ethernet uses a bus orstar topology with twisted-pairwiring, coaxial cable, or fiberoptic cable transmissionmedia. Newer protocolsinclude Fast Ethernet, whichoperates at 100 Mbps, GigabitEthernet which operates at 1Gbps, and 10G Ethernet,which operates at 10 Gbps.

netiquette


16 Intranet, Extranet, and InternetAn intranet is a network that is used by a single organization, such as

a corporation or school, and is only accessible by authorized users. Thepurpose of an intranet is to share information. However, a firewall isalso used to lock out unauthorized users. A firewall is a network securitysystem that prevents unauthorized network access.

An extranet extends an intranet by providing various levels ofaccessibility to authorized members of the public. For example, acorporation may extend their intranet to provide access to specificinformation, such as their ordering system, to registered customers.

The largest and most widely accessed network is the Internet, aworldwide network of computers that is not controlled by any oneorganization. The Internet has had an undeniable impact on modernsociety because it allows users worldwide to communicate in a matterof seconds.

The Internet is actually numerous networks all linked together throughrouters. A router is a device that can connects different network technolo-gies together. Networks connected to routers use TCP/IP (TransmissionControl Protocol/Internet Protocol) software to communicate.

Computers on the Internet are either servers or clients. The client issent information from a server. The client/server structure of the Internetis called interactive because the information accessed is a result ofselections made by the user. For example, a computer with just minimalsoftware for accessing the Internet is a client. The client user selectingoptions from the Internet is receiving the information from a server, acomputer with additional software and files that is also connected tothe Internet.

17 Accessing the InternetMany organizations link their networks to the Internet. Individuals

can get access to the Internet through telecommunications and an Internetservice provider or an online information service. An ISP (InternetService Provider) offers access to the Internet for a fee. An onlineinformation service, such as AOL, offers access to the Internet as well asother services for a fee.

ISPs and online information services typically charge a fee that isusually a flat, monthly rate, but is sometimes based on access time. Theyalso provide the necessary software, a user name, password, and dial-up number for a conventional modem.

18 TelecommunicationsTelecommunications is the transmitting and receiving of data. Data can

be in various forms including voice and video. Telecommunicationsrequires a modem or adapter and a line or cable. The speed of datatransmission is measured in Kbps (thousands of bits per second) or Mbps(millions of bits per second). Numerous telecommunications options areavailable, which vary in speed and cost:

History of the InternetThe history of the Internet canbe traced to an early networkknown as ARPANET.

ARPANET was created in thelate 1960s by the Departmentof Defense’s ARPA (AdvancedResearch Projects Agency.)ARPANET initally connectedcomputers at the University ofCalifornia Los Angeles and theStanford Research Institute.

The Internet evolved fromARPANET and the theory ofopen architecture networking,meaning internetworking dif-ferent networks regardless ofwhat type of network technol-ogy they used.

intranet

firewall

extranet

Internet

router

Kbps, Mbps


• A conventional modem uses standard telephone lines to convertanalog signals to digital data. A conventional modem is a 56Kbps modem, which transmits data at 28.8 Kbps and 36.6 Kbps,and receives data at 56 Kbps. Home computers sometimes usea conventional modem.

• A DSL (Digital Subscriber Line) modem uses standard telephonelines with data transmission up to 640 Kbps. Data receipt isfrom 1.5 Mbps to 9 Mbps. ADSL (Asymmetric DSL) is the mostcommon form used.

• A cable modem transmits data through a coaxial cable televisionnetwork. Data transmission is from 2 Mbps to 10 Mbps anddata receipt is from 10 Mbps to 36 Mbps.

• Leased/Dedicated lines are being used by many businesses andschools for Internet access. They allow for a permanent con-nection to the Internet that is always active. The cost of a leasedline is usually a fixed monthly fee. A T-1 carrier is a type ofleased line that transmits data at 1.544 Mbps.

• ISDN (Integrated Services Digital Network) is a digital tele-phone network provided by a local phone company. ISDN iscapable of transmitting and receiving data at up to 64 Kbps.ISDN requires the use of an ISDN terminal adapter instead ofa modem.

19 Internet ServicesThe most widely used Internet service is the World Wide Web (WWW),

also called the Web. The Web can be used to search and access informa-tion available on the Internet. A Web browser application, such asMicrosoft Internet Explorer, provides a graphical interface to presentinformation in the form of a Web site. Each Web site consists of a series ofrelated Web pages. The Web page below is a part of the CNN Web site:

Conventional ModemA conventional modem con-verts a computer’s binary datainto tones that can be trans-mitted over phone lines. Toreceive data, a modem con-verts the tones from the phoneline into binary data. This pro-cess involves what is calledsignal modulation anddemodulation, hence thename modem.

Web

Web site


Another widely used Internet service is e-mail or electronic mail, whichallows an individual with an e-mail account to send messages to an-other person with an e-mail account. E-mail can be received in a matterof seconds, even if the recipient is located half way around the world.

A very popular service provided through the Internet and onlineinformation service providers is called Internet Relay Chat (IRC) or justchat. IRC was developed in 1988 by Jarkko Oikarinen. Chatting iscommunicating with someone else who is also online by typing messagesback and forth to each other. After one person writes something theother person receives the message and replies. Although there may be ashort delay while the person responds, chatting is considered to be areal-time event. Real time means that data reflects an event as it occurs.

A bulletin board service, sometimes referred to as a BBS, allows a userto participate in a discussion group. There are thousands of bulletinboard services with topics ranging from accounting to zoology. Busi-nesses often maintain a bulletin board service for their employees only.Other bulletin board services allow any network user to join.

Network news is a popular BBS available on the Internet. This systemuses the term newsgroup to refer to an individual bulletin board, andarticle refers to the message posted to the newsgroup. Subscribers of anewsgroup can check for new articles and post (send) articles regardingthe topic of discussion. USENET refers to the collection of all the serversthat offer network news.

Internet users can also join a listserv. A listserv is a discussion groupthat uses e-mail to send messages. LISTSERV is a program that maintainsthe mailing list, a list of the e-mail addresses of the users who subscribeto the listserv. When a subscriber posts a message to a listserv, everysubscriber receives a copy of the message.

HTTP (Hypertext Transfer Protocol) is used for handling thetransmission of pages between a Web server and a Web browser.

FTP (File Transfer Protocol) is used to rapidly transfer (upload anddownload) files from one computer to another over the Internet.

Telnet is a program that is used on networks such as the Internet toallow users to remotely log on to a server on the network. The servercan then be controlled from the remote computer. Telnet is commonlyused to control Web servers.

WAIS (Wide Area Information Server) is a Unix-Based system forsearching the Internet using a natural language processor. However, aWAIS search often includes many false matches.

Gopher was one of the first widespread Internet browsing services. Itis a text-based environment that is used to locate information on theInternet.

e-mail

IRC

BBS

network news

articlenewsgroup

USENET

listserv

mailing listLISTSERV

gopher

FTP

Telnet

HTTP

WAIS


20 Internet Privacy IssuesThe growth of the Internet has caused additional concerns about

personal privacy. Searching for information on the Internet is not asanonymous as it might seem.

The collection of data about consumers visiting a Web site is amarketing technique known as online profiling. When a commercial Website is visited, information about the user may be collected using variousmethods such as cookies or Web beacons.

A cookie is a text file created by the server computer when a user entersinformation into a Web site. The cookie file is then stored on the user’scomputer and accessed each time the user visits that Web site. Cookiesare often created when online purchases are made. Although cookiescan only store information that the user has selected or entered, theiruse has raised concerns over privacy issues.

Web beacons, also called Web bugs, are tiny, transparent graphics locatedon Web pages and are used to collect data about the Web page user.Usually the monitoring is done by an outside advertising company. Theinformation a Web beacon collects includes the IP address of thecomputer, the URL being visited, the time the Web page was viewed,the type of browser being used, and the cookie file.

Before providing a company with personal information through a Website, check the site’s privacy policy. A privacy policy is a legally bindingdocument that explains how any personal information will be used.

The Internet has also opened up access to many files that werepreviously inaccessible. To protect both the privacy of an individual andthe accuracy of data stored about individuals, several laws have beenpassed:

• The Electronic Communications Privacy Act of 1986 (ECPA)makes it a crime to access electronic data without authorization.It also prohibits unauthorized release of such data.

• The Electronic Freedom of Information Act of 1996 (E-FOIA)requires federal government agencies to make certain agencyinformation available for public inspection and is designed toimprove public access to agency records by making moreinformation available online.

• The Children’s Online Privacy Protection Act of 1998 (COPPA)requires commercial Web sites that collect personal informationfrom children under the age of 13 to obtain parental consent.

• The Safety and Freedom through Encryption Act of 1999(SAFE) gives Americans the freedom to use any type ofencryption to protect their confidential information.

cookies

online profiling

Web beacon

EncryptionEncryption is the process oftranslating data into a codethat is not readable withoutthe key to the code. Encryp-tion prevents unauthorizedaccess to data. Data that isencrypted is referred to ascipher text.

privacy policy


21 Acceptable Use PolicyConcerns about Internet content, unproductive use, and copyright

have prompted many schools and businesses to develop an AcceptableUse Policy or Internet Use Agreement. Acceptable Use Policies typicallycontain rules similar to:

• Use appropriate language.

• Do not reveal personal address or phone numbers.

• Do not access, upload, download, or distribute inappropriatematerials.

• Do not access another user’s account.

• Use of the network for private business is prohibited.

• Only administrator installed software may be used on thecomputers. Adding, deleting, or modifying installed softwareis not permitted.

22 The Social and EthicalImplications of Computers

The society in which we live has been so profoundly affected bycomputers that historians refer to the present time as the informationage. This is due to the our ability to store and manipulate large amountsof information (data) using computers. As an information society, wemust consider both the social and ethical implications of our dependenceon computers. By ethical questions we mean asking what are the morallyright and wrong ways to use computers.

Probably the most serious problem associated with computers is thepossibility of invading our privacy. Because computers can store vastamounts of data we must decide what information is proper to store,what is improper, and who should have access to the information. Everytime you use a credit card, make a phone call, withdraw money, reservea flight, or register at school, a computer records the transaction. Theserecords can be used to learn a great deal about you—where you havebeen, when you were there, and how much money was spent. Shouldthis information be available to everyone?

Computers are also used to store information about your credit rating,which determines your ability to borrow money. If you want to buy acar and finance it at a bank, the bank first checks your credit records ona computer to determine if you have a good credit rating. If you purchasethe car and then apply for automobile insurance, another computer willcheck to determine if you have traffic violations. How do you know ifthe information being used is accurate? The laws listed on the next pagehave been passed to help ensure that the right to privacy is not infringedby the improper use of data stored in computer files:

information age


• The Fair Credit Reporting Act of 1970 gives individuals theright to see information collected about them for use by credit,insurance, and employment agencies. If a person is denied creditthey are allowed to see the files used to make the credit deter-mination. If any of the information is incorrect, the person hasthe right to have it changed. The act also restricts who mayaccess credit files to only those with a court order or the writ-ten permission of the individual whose credit is being checked.

• The Privacy Act of 1974 restricts the way in which personaldata can be used by federal agencies. Individuals must be per-mitted access to information stored about them and may cor-rect any information that is incorrect. Agencies must insure boththe security and confidentiality of any sensitive information.Although this law applies only to federal agencies, many stateshave adopted similar laws.

• The Financial Privacy Act of 1978 requires that a governmentauthority have a subpoena, summons, or search warrant to ac-cess an individual’s financial records. When such records arereleased, the financial institution must notify the individual ofwho has had access to them.

23 Protecting Computer Softwareand Data

As society becomes more and more reliant on digital information,copyright and exposure to malicious code have become two importantissues among computer users. Copyright is protection of digital infor-mation. Copyright infringement is the illegal use or reproduction of data(text, pictures, music, video, and so on). There are now laws that pro-tect against copyright infringement, and several well-known cases ofhigh penalties for individuals guilty of copyright infringement.

Copyright infringement includes duplication of computer softwarewhen copies are being used by individuals who have not paid for thesoftware. This practice is called piracy when illegal copies are distributed.Developing, testing, marketing, and supporting software is an expensiveprocess. If the software developer is then denied rightful compensation,the future development of all software is jeopardized. Therefore, it isimportant to use only legally acquired copies of software, and to notmake illegal copies for others.

Malicious code comes in many forms and is delivered in many ways.Virus, Trojan horse, and Internet worm are three forms of maliciouscode. They can appear on a system through executable programs, scripts,macros, e-mails, and some Internet connections. One devastating effectof malicious code is the destruction of data.

A virus is a program or series of instructions that can replicate withoutthe user’s knowledge. Often a virus is triggered to run when given acertain signal. For example, a virus might check the computer’s clockand then destroy data when a certain time is reached. A virus is easilyduplicated when the file is copied, which spreads it other computers,hence the name virus.

piracy

malicious code

virus

copyrightcopyright infringement


A Trojan horse program appears as something else, usually a programthat looks trustworthy. Running the program runs the malicious codeand damages files on the computer. Worms are a threat because of theway they replicate and use system resources, sometimes causing thesystem to shut down.

Malicious code has become so widespread that software calledantivirus programs are typically installed on computers and networks todetect and remove the code before it can replicate or damage data.Precautions can also be taken to prevent damage from malicious code:

• Update antivirus software. An antivirus program can only de-tect the viruses, Trojan horses, and worms it is aware of.Antivirus programs have a Web link for updating the virusdefinitions on the computer containing the antivirus program.

• Do not open e-mail attachments without scanning for maliciouscode. One estimate states that 80% of virus infection is throughe-mail.

Newspapers have carried numerous reports of crackers, or hackers,gaining access to large computer systems to perform acts of vandalism.This malicious act is illegal and can cause expensive damage. TheElectronic Communications Privacy Act of 1986 specifically makes it afederal offense to access electronic data without authorization. Networksusually include a firewall, which is a combination of hardware andsoftware, to help prevent unauthorized access.

The willful destruction of computer data is no different than any othervandalization of property. Since the damage is done electronically theresult is often not as obvious as destroying physical property, but theconsequences are much the same. It is estimated that computer crimescost the nation billions of dollars each year.

24 IT CareersThe growth of computers, the Internet, and the Web have created

many new job opportunities in the IT (Information Technology) field.IT encompasses all aspects of computer-related technology. It is alsoreferred to as MIS (Management Information Services) and IS(Information Services).

Education requirements for IT careers vary widely. However, a formaleducation, such as an undergraduate degree in computer science,engineering, or business, is often required. A graduate degree may alsobe required in highly specialized fields. Some careers require aspecialized certification course in an area such as networking. Otherskills that are required in this industry are teamwork, problem-solvingskills, oral and written communication, up-to-date technical knowledge,and computer experience.

Trojan horse

cracker, hacker

worm

firewall

antivirus program

IT

MIS, IS


A data-entry operator types data into a computer. Data-entry opera-tors may work for banks entering cancelled checks, department storesentering inventory figures, or educational institutions entering studentrecords. A data-entry operator should possess a high school diplomaor associate degree and the ability to type quickly and accurately.

A system analyst designs and manages data-processing and otherbusiness applications. The analyst must determine how an organizationwill use the computer system, what data will be stored, how it will beaccessed, and how the system is expected to grow in the future. A systemanalyst should possess a comprehensive knowledge of data-processingmethods, software, hardware, and programming languages. Mostsystem analysts are college graduates who have majored in computerscience or information systems or both.

The programmer creates software based on a design and specification.A programmer should possess a detailed knowledge of the program-ming language or languages being used as well as an ability to reasonanalytically and pay close attention to details. Many businesses employprogrammers who have graduated from a technical school or commu-nity college with a degree in programming. Large or specialized com-panies, which need highly sophisticated programming, usually requireemployees with a four-year college degree and/or previous experience.

The MIS department in some companies is very large and requires amanager who must organize the computer and human resources of thedepartment in order to best achieve the organization’s goals. An MISmanager should possess a detailed understanding of data-processingmethods, hardware, and software. A college degree in business admin-istration with a concentration in information systems is usually required.

The study of computer science is a very broad field involving manydisciplines including science, electronics, and mathematics. A computerscientist often works in research at a university or computer manufac-turer developing new computer applications software and hardware. Itis computer scientists who design and develop robots, natural languageprocessors, and the many applications that we have mentioned. A com-puter scientist usually has both undergraduate and graduate degrees incomputer science.

Computer engineers design and manufacture computers. This field isbroad and includes engineers who develop new computer applications.Other engineers translate ideas produced by researchers into manufac-tured products. A computer engineer usually possesses both under-graduate and graduate degrees in engineering.

The people who help build computer systems need to possess the abil-ity to work well with tools. Manufacturing workers usually have earneda high school diploma or community college degree. Good preparationfor such a career includes taking courses in mechanical arts as well asscience and mathematics.

Working over the phone, through e-mail, and online forums, technicalsupport technicians assist users with questions on a company’s products.A technical support technician is usually a graduate of a technical schoolor community college.

data-entry operator

systems analyst

programmer

manager

computer scientist

computer engineer

manufacturing worker

technical supporttechnician


A large number of people sell computers either as representatives whotravel and visit clients or as salespeople in computer stores. It isimportant that they possess a thorough knowledge of the computerequipment they sell and be able to explain how it may be used. Thelevel of education required for this job will depend on the sophisticationof the equipment being sold. Often a high school or community collegedegree is sufficient. The knowledge required to sell large computersystems may be require a four-year college degree.

Employees currently working in a computer-related field are oftenthere because of computer teachers. In high schools and colleges, teachersand professors do research and teach all aspects of computing from com-puter science to ethics. For teaching at the high school level, a four-yearcollege degree in a computer field is the minimum. At the college level,a graduate degree is the minimum requirement.

At most educational institutions, it is the job of the technologycoordinator to plan and oversee the acquisition, distribution, and utili-zation of computer technology. Schools require such a person to ensurethat they have working computer facilities and are keeping up with newadvancements in technology. A graduate degree in a computer field isoften required.

Intranet analysts set up and maintain an intranet for a company ororganization. This involves managing company intranet projects,technical support, and creating reports. This job requires technicalknowledge of networks, network security features, computers, andsoftware as well as personal communication skills.

A network administrator is responsible for a company’s network. Du-ties could include installing the network hardware and software, as wellas maintaining the network so it runs properly. LAN manager is anotherterm for network administrator.

IT careers also include Web careers, a job market that is continuallyexpanding and changing. Web career job titles, duties, and educationand experience requirements vary from company to company. Typicallythe larger the company, the more specialized the job will be. For example,in a large company, a Web developer may just implement a Web site.Whereas, in a small company the Web developer may design, implement,and maintain the Web site.

Web professionals often specialize in areas of expertise such asinformation architecture, programming, graphics, animations, ormarketing, to name just a few. Job experience and specialized trainingare usually required to gain expertise in a particular area. Typical Webcareer titles and job descriptions include:

Web developers design, build, and program Web sites. They determinethe Web site strategy, which includes the hardware to be used and thedesign and navigation of the site. They also design tools, such as re-ports and databases, to measure the success of the Web site.

Web developers require programming and technical skills. Often thedevelopment is divided into back-end development and front-enddevelopment. Back-end development involves designing the hardwareand database infrastructure, such as where orders are fulfilled. Front-enddevelopment involves the navigation and design of the Web site.

sales

computer teacher

technology coordinator

Web careers

Web developer

intranet analyst

network administrator


Web designers create the Web page layouts and graphics for Web sites.The work a Web designer does usually determines whether users willstay at a Web site. Their job involves presenting Web pages so they areinteresting and accessible.

A Web designer requires knowledge of HTML, Web implementationsoftware such as Dreamweaver and Flash, and graphic editing softwaresuch as Fireworks, PhotoShop, or Illustrator. Since technology changesrapidly, Web designers must keep up-to-date on new technologies, tech-niques, and design standards.

Webmaster responsibilities can include designing and creating Webpages and maintaining the site. A Webmaster is also responsible for an-swering e-mail about the Web site. A Webmaster possesses extensiveInternet knowledge, programming skills, and design experience.

Web authors create textual content for Web pages. A Web author hasgood writing skills and carefully considers the text as it will be pre-sented on the Web.

There are also many small to large companies that provide IT ser-vices. These companies include:

• ISPs (Internet Service Providers) provide access to the Internet.Employees have a wide range of technical knowledge aboutnetworks, computers, and software since clients will have avariety of equipment. Personal communication skills are alsonecessary for sales and technical support.

• Web hosts provide space on a server where users can post theirWeb pages. Employees have technical knowledge of networks,computers, and the World Wide Web. Personal communica-tion skills are also necessary for sales and technical support.

25 The Ethical Responsibilitiesof an IT Professional

Working as an IT professional includes taking responsibility for theethical aspects of a career choice. For example, IT professionals involvedin creating software must ensure, as best he or she can, the reliability ofthe computer software. This means the ethical responsibility of the ITprofessional includes using the appropriate tools and methods to testand evaluate programs before distribution. A special cause for concernis the increased use of computers to control potentially dangerousdevices such as aircraft, nuclear reactors, or sensitive medical equipment.

IT professionals must also consider the impact they have on computerusers. Web users for example often rely on data from Web sites providingreal-time information. The information displayed is determined with aprogram written using a 4GL or other language that accesses a database.The IT professionals involved in such a project have the ethicalresponsibility to possibly millions of individuals for ensuring, as bestthey can, accurate data retrieval.

Web designer

Webmaster

Web author

ISP

Web host


As capable as computers have proven to be, we must be cautious whenallowing them to replace human beings in areas where judgement iscrucial. As intelligent beings, we can often detect that something out ofthe ordinary has occurred which has not been previously anticipatedand then take appropriate actions. Computers will only do what theyhave been programmed to do, even if it is to perform a dangerous act.

Chapter Summary

The earliest computing devices were mechanical and were unreliable.The advent of electricity brought about electromechanical machines, andlater first generation computers that used vacuum tubes. The architec-tural design of computers changed with the idea of a machine that couldperform many different tasks by simply changing its program. With thedevelopment of the transistor came second generation computers thatwere smaller and faster. Third generation computers used integratedcircuits. Fourth generation computers include an entire CPU on a singlechip.

Machine language is the only language a computer can understand.Machine language is a low-level language. Also a low-level language,but with names to represent instructions, assembly language was easierto use. An assembler must be used to convert an assembly languageprogram to machine language. Languages with English-like instructionsare high-level programming languages. A compiler is used to convert aprogram in a high-level language to assembly language. Fortran, COBOL,Ada, and C are all early high-level languages.

An interpreter translates and runs instructions line by line, rather thancompiling code. BASIC is a programming language that uses aninterpreter. In the 1980s, object-oriented programming (OOP) evolvedout of the need to better develop complex programs in a systematic,organized approach. OOP includes modules of code called classes andrequires a compiler. Visual Basic .NET, C++, C#, and Java are OOPlanguages.

The physical components of the PC are called hardware. The PCaccepts data from input devices, and then output devices display orstore processed data. Peripheral devices, such as printers and scanners,enhance the versatility of PCs.

The base unit of a desktop PC contains many components including amotherboard with a CPU, ROM, RAM, SRAM, expansion cards, the databus, the address bus, and the control bus. A CPU includes an ALU anddirects the processing of information throughout the computer. Thespeed at which a CPU can execute instructions is determined by thecomputer’s clock rate, measured in megahertz (million of cycles persecond). Since RAM storage is temporary, data is written to storagemedia, such as a floppy diskette, hard disk, zip disk, or CD-R.

PCs contain software that instructs the computer what to do.Operating system software is run automatically when the computer isturned on and enables the user to communicate with the computer.Applications software is written to perform specific tasks.


Mobile computing includes portable computers with miniaturizedcomponents and long-lasting batteries. The notebook PC has many ofthe same functions and features of the desktop PC. The tablet PC can beheld and written on like a tablet of paper. Tablets are either slate orconvertible and include handwriting recognition software. Handheldsare widely used because of their size, software applications includingscheduling, contact information, word processing, and spreadsheet, andcellular phone and Internet access options. Wearable computers comein many sizes with varying application that includes clothing with anMP3 player, goggles with digital camera, ear bud, and microphone, andwrist-top computers with handheld PC features.

The electrical circuits of an IC have one of two states, off or on.Therefore, the binary number system is used to represent the two states:0 for off and 1 for on. Each 0 or 1 in binary code is called a bit and a 8-bit unit is called a byte. Our most familiar number system is the decimalor base 10 system. The binary number is a base 2 system and thehexadecimal system is base 16.

Every letter of an alphabet and every symbol of a culture have beengiven a representation in a digital code called Unicode. Unicode uses aset of sixteen 1s and 0s to form a 16-bit binary code for each symbol.

Computer memory, file sizes, and storage device capacities are mea-sured in bytes. In computers and electronics MB stands for megabytes,GB stands for gigabtyes, and K stands for kilobytes.

The binary representation of an integer number is usually stored infour bytes of memory. Real numbers are numbers that contain decimalpoints and the binary representation of a real number is usually storedin one byte or one word of memory.

A network is a combination of software and hardware that allowscomputers to exchange data and to share software and devices, such asprinters. Hardware requirements include a network interface card, andsoftware requirements include an operating system to allow the user tocommunicate with the computer.

Networks are classified by their size, architecture, topology, andprotocol. Common network size classifications are LAN and WAN. Twocommon network architecture models are client/server and peer-to-peer.Client/server networks include a server computer with more RAM, alarger hard disk, and sometimes multiple CPUs. Networks are managedwith network operating system software. Topology refers to the physicalarrangement of the nodes on a network. Three common physicaltopologies are the bus, star, and ring topology. One widely used protocolis Ethernet. Network users should follow netiquette.

An intranet is a network that is used by a single organization and isonly accessible by authorized users. A firewall is a network securitysystem that prevents unauthorized network access. An extranet extendsan intranet by providing various levels of accessibility to authorizedmembers of the public.


The largest and most widely accessed network is the Internet. Themost widely used Internet service is the World Wide Web (WWW), alsocalled the Web. Another widely used Internet service is e-mail. OtherInternet services include IRC, BBS, network news, listserv, HTTP, FTP,Telnet, WAIS, and gopher.

Telecommunications is the transmitting and receiving of data.Telecommunication options include a conventional modem, a DSLmodem, a cable modem, leased/dedicated lines, and ISDN. Access tothe Internet also requires the use of an ISP or an online informationservice.

The growth of the Internet has caused concerns about personal privacy.Online profiling, cookies, and Web beacons are all areas of concern.Before providing personal information through a Web site, check thesite’s privacy policy. To protect an individual’s privacy, several lawshave been passed.

Concerns about Internet content, unproductive use, and copyrighthave prompted many schools and businesses to develop an AcceptableUse Policy, also called an Internet Use Agreement.

Historians refer to our present time as the information age. The po-tential for the use of computers to invade our right to privacy hasprompted legislation to protect individuals.

Copyright and malicious code have become two important issuesamong computer users. Copyright infringement include illegal use orreproduction of software. Piracy is distributing illegally duplicatedsoftware. Malicious code includes viruses, Trojan horses, and worms.Malicious code is delivered through programs, scripts, macros, e-mails,and Internet connections. One devastating effect of malicious code isthe destruction of data. Antivirus programs should be used to detectand remove malicious code. Crackers, also called hackers, areindividuals who gain access to a computer system to perform acts ofvandalism. Networks often include a firewall to prevent suchunauthorized access.

IT encompasses all aspects of computer-related technology. IT is alsoreferred to as MIS or IS. Education requirements for IT careers vary.Careers include teaching, programming, and Web-related careers.Choosing an IT career includes taking responsibility for the ethicalaspects of the career choice. IT professionals must also consider theimpact that have on computer users.


Vocabulary

Ada A high-level programming language that sup-ports real-time applications.

Address A unique binary representation of a loca-tion in memory.

Address bus Carries memory addresses that indi-cate data storage locations.

ALU (Arithmetic Logic Unit) The part of the CPUthat handles arithmetic and logic operations.

Applications software Program written to performa specific tasks.

Article A message posted to a newsgroup.

Assembler A program that translates an assemblylanguage program into machine language.

Assembly language A low-level language com-prised of names that represent machine languageinstructions.

Base unit Housing that contains the motherboard,CD-RW drive, diskette drive, and hard disk drive.

BASIC A high-level programming language devel-oped by John Kemeny and Thomas Kurtz. Uses aninterpreter to translate code into instructions thecomputer understands.

Binary number system Number system used bymodern computers—uses only digits 0 and 1. Alsocalled Base 2.

Bit (BInary digiT) A single 0 or 1 in binary code.

BBS (bulletin board service) A network servicethat allows a user to participate in a discussion group.

Bus A set of circuits that connect the CPU to othercomponents.

Bus topology A LAN topology where each node ofa network is connected to a single shared communi-cation cable called a bus.

Byte A group of 8 bits.

C A high-level programming language developedby Dennis Ritchie. Requires less memory that otherlanguages.

C++ A high-level OOP language.

C# A high-level OOP language.

Cable modem A modem that transmits data througha coaxial cable television network.

Cache High-speed memory used to store frequentlyused data so that it can be quickly retrieved by anapplication. See also SRAM.

Chat See IRC.

Class An OOP language module that contains codethat groups related data and actions.

Client/Server network A group of computers, calledclients, connected to a server.

Clock rate The speed at which a CPU can executeinstructions, measured in megahertz or gigahertz.

COBOL A high-level programming languagedesigned by Grace Murray Hopper. Used widely forbusiness applications.

Compiler A computer program that translates ahigh-level program into assembly language.

Computer An electronic machine that accepts data,processes it according to instructions, and providesthe results as new data.

Control bus Carries control signals.

Conventional modem A modem that uses stan-dard telephone lines to convert analog signals todigital data.

Convertible A tablet PC that uses both a stylus anda keyboard for input.

Cookie Text file created by the server computerwhen a user enters information at a Web site.

Copyright The protection of digital information.

Copyright infringement The illegal use or repro-duction of data.

CPU (Central Processing Unit) Processes data andcontrols the flow of data between the computer’sother units. Also contains the ALU. Located on themotherboard.

Cross-platform connectivity The ability for onetype of PC to link to and share data with a differenttype of PC.

Data bus Transfers data between the CPU, memory,and other hardware devices on the motherboard.


Decimal number system The base 10 number sys-tem with digits 0 through 9.

Dedicated line See Leased line.

DSL (Digital Subscriber Line) modem A modemthat uses standard telephone phone lines. ADSL isthe most common form used.

E-mail (electronic mail) An Internet service thatallows an individual with an e-mail account to sendmessages to another person with an e-mail account.

Expansion board A circuit board that connects tothe motherboard. Contains components for a par-ticular purpose.

Extranet An extended intranet that provides variouslevels of access to authorized members of the public.

Firewall A network security system that preventsunauthorized network access.

Fortran A high-level programming language.

FTP (File Transfer Protocol) Used to rapidly uploadand download files from one computer to anotherover the Internet.

GB (gigabyte) 1,073,741,820 bytes.

Gigahertz One billion cycles per second.

Gopher One of the first widespread Internetbrowsing services.

Hacker Person who gains access to a computersystem without authorization. Also called cracker.

Handheld PC A mobile computing device that iswidely used because of its small size. Input is througha stylus and applications include scheduling, spread-sheets, word processors, and sometimes handwrit-ing recognition. Also available with a cellular phoneand Internet access. Also called a PDA.

Hardware The physical components of the PC.

Hexadecimal system Number system based on 16digits. Also called base 16.

High-level language A computer language withEnglish-like instructions.

Hub A device that joins communication lines at acentral location on the network.

HTTP (Hypertext Transfer Protocol) Used forhandling the transmission of pages between a Webserver and a Web browser.

IC (Integrated Circuit) A silicon wafer with intri-cate circuits etched into its surface and then coatedwith a metallic oxide to allow the circuits to conductelectricity. Also called a chip.

Information age Current time characterized by ourincreasing dependence on computers and our abil-ity to store and manipulate large amounts of infor-mation using computers.

Input device Gives data to the PC.

Interactive Information accessed as a result ofselections made.

Internet The largest and most widely accessednetwork.

Interpreter Executes code without completely con-verting a program to machine language. Used by theBASIC programming language.

Intranet A network that is used by a single organi-zation and is only accessible by authorized users.

IRC (Internet Relay Chat) An Internet and onlineinformation service that allows users to communi-cate with someone online by typing messages backand forth.

ISDN (Integrated Services Digital Network) Adigital telephone network provided by a local tele-phone company.

ISP (Internet Service Provider) A company thatoffers access to the Internet for a fee.

IT (Information Technology) A term that encom-passes all aspects of computer-related technology.

Java A high-level OOP language.

K (kilobyte) 1,024 bytes.

Kbps Thousands of bits per second.

LAN (Local Area Network) A network that connectsdevices within a small area.

Leased line A telecommunication option used fora permanent connection to the Internet that is alwaysactive.

Listserv A discussion group that uses e-mail to sendmessages.

Low-level language A computer language thatdirectly addresses a computer’s hardware.

Machine language The only language that a com-puter understands. It is a low-level language withinstructions comprised of just 1s and 0s.


Mailing list A list of e-mail addresses of the userswho subscribe to a listserv.

Mainframe Computer system that supports multi-user applications.

Megahertz One million cycles per second.

Memory ICs located on the motherboard that storedata electronically.

MB (megabyte) 1,048,576 bytes.

Microcomputer A computer that fits on a desktopand uses a microprocessor. Also called a PC or Mac.

Microprocessor An entire CPU on a single chip.

Motherboard The main circuit board inside thebase unit.

Mbps Millions of bits per second.

Nanosecond One billionth of a second.

Netiquette Network etiquette.

Network A combination of software and hardwarethat allows computers to exchange data and to shareapplications software and devices.

Network architecture Includes the type ofcomputers on the network and determines hownetwork resources are handled.

Network interface card A circuit board that goesinto the computer or other device on a LAN.

Network news A BBS available on the Internet.

Network OS Network operating system. Softwarethat allows users and devices to communicate overthe network.

Newsgroup An individual bulletin board.

Node A location on the network with a device thatis capable of communicating with other networkdevices.

Notebook PC A mobile computing device that hasa CPU, memory, and hard disk space comparable tothat of a typical desktop PC.

Online information service A company that offersaccess to the Internet as well as other services for afee.

Online profiling A marketing technique that collectsdata about consumers visiting a Web site.

OOP (object-oriented programming) A program-ming approach that evolved out of the need to betterdevelop complex programs in a systematic, orga-nized approach.

Operating system software Software that allowsthe user to communicate with the computer.

Output device Displays or stores processed data.

Overflow error An error that occurs when the num-ber of bits that are needed to represent the integer isgreater than four bytes.

PC A computer that uses a microprocessor.

Peer-to-Peer network Networked computers thatshare responsibilities and resources equally.

Peripheral device A device attached to a PC.

Piracy The illegal duplication and distribution ofsoftware.

Privacy policy A legally binding document thatexplains how personal information will be used.

Program A sequence of instructions written in acode that the computer understands.

Protocol A standard.

RAM (Random Access Memory) Memory that tem-porarily stores data and instructions.

Read Access data.

Real numbers Numbers that contain decimal points.Also called floating point numbers.

Real time Data that reflects an event as it occurs.

Ring topology A LAN topology where each nodeof a network is connected to form a closed loop.

ROM (Read Only Memory) Memory that storesdata that is a permanent part of the computer.

Roundoff error An error that occurs when there arenot enough bits to hold the mantissa.

Router A device that connects different networktechnologies.

Scanner An input device that uses a laser to createa digital image from artwork.

Server A computer with more RAM, a larger harddisk, and sometimes multiple CPUs that is used tomanage network functions.

Slate A tablet PC that uses just a stylus for input.

Software A program.


SRAM (Static Random Access Memory) High-speedmemory referred to as cache.

Star topology A LAN topology where each node ofa network is connected to a hub, which is a devicethat joins communication lines at a central locationon the network.

Storage media Used to store data.

Tablet PC A mobile computing device that can becompared to a pad of paper and a pencil. Input isusually from a stylus and tablet PCs come with hand-writing recognition software. See also slate and con-vertible.

TCP/IP (Transmission Control Protocol/InternetProtocol) software Software used by networksconnected to routers to communicate.

Telecommunications The transmitting andreceiving of data.

Telnet A program that is used on networks such asthe Internet to allow users to remotely log on to aserver on the network.

Terminal A keyboard and monitor used to commu-nicate with a mainframe.

Topology The arrangement of the nodes on a net-work.

Trojan horse Malicious code in the form of a pro-gram that appears as something else, usually a pro-gram that looks trustworthy.

Transistor A semiconductor device that replacedthe vacuum tube.

Unicode A digital code that uses a set of sixteen 1sand 0s to form a 16-bit binary code for each symbol.

USENET The collection of servers that offer net-work news.

Virus Malicious code in the form of a program orseries of instructions that replicate without the user’sknowledge.

Visual Basic .NET A high-level OOP language.

WAIS (Wide Area Information Server) A Unix-based Internet service that is used for searching theInternet.

WAN (Wide Area Network) A network that con-nects computers over large geographical distances.

Wearable computer A mobile computing devicethat is incorporated into clothing, eyewear, and wrist-wear, and other wearables.

Web See World Wide Web.

Web beacon A tiny, transparent graphic used on aWeb page to collect data about the Web page user.Also called a Web bug.

Web site A series of related Web pages.

Word Bits grouped in units of 16 to 64.

World Wide Web (WWW) The most widely usedInternet service.

Worm Malicious code that replicates and uses sys-tem resources. Often associated with the Internet.

Write Store data.


Review Questions

Sections 1 — 41. Describe the Pascaline and explain what math-

ematical operation it was designed to perform.

2. a) What mathematical operations was theStepped Reckoner supposed to perform?

b) Why did it tend to malfunction?

3. What did Ada Byron mean when she said thatthe Analytical Engine could never “originateanything”?

4. a) For what purpose did Herman Hollerithinvent his tabulating machine?

b) What were punched cards used for in thetabulating machine?

5. Why wasn’t the Mark 1 considered a computer?

6. What number system did the Atanasoff-BerryComputer use?

7. For what purpose was the ENIAC originallydesigned?

8. What is a computer?

9. In what way did Alan Turing and John vonNeumann improve upon the design of theENIAC?

10. a) What is a program?b) What is machine language?c) List the first three computers designed to use

a stored program.

Sections 5 — 1411. How did the invention of the transistor affect

the development of computers?

12. How did the use of magnetic tape improve datastorage?

13. a) What is a low-level language?b) List two low-level languages.c) What does an assembler do?d) What is a high-level programming language?e) What does a compiler do?f) Who developed COBOL?g) List three high-level programming languages.

14. Explain what ICs are and why they have beenimportant in the development of computers.

15. a) What is a mainframe?b) What is the usual way for a person to com-

municate with a mainframe?

16. Why was the invention of the microprocessorimportant to the development of computers?

17. List some of the advantages of a microcomputercompared with the ENIAC or UNIVAC.

18. What is an interpreter?

19. a) Why was object-oriented programmingdeveloped?

b) List four object-oriented programminglanguages.

20. a) What is hardware?b) What are input and output devices used for?c) What is a peripheral device?

21. List and describe five components found on themotherboard.

22. List three examples of storage media.

23. Describe the flow of data between the compo-nents of a computer.

24. In what way was the design of Babbage’s Ana-lytical Engine similar to the modern computer?

25. a) Describe one difference between operatingsystem software and applications software.

b) What is another name for software?

26. List four types of mobile computing devices.

27. What is a stylus used for?

28. Explain one type of wearable computer.

29. What is meant by cross-platform connectivity?

30. Why was the binary number system adoptedfor use in computers?

31. Explain what a bit and a byte are.


32. a) What is the decimal equivalent of 1112?b) What is the decimal equivalent of 2C16?

33. What is Unicode?

34. a) How many bytes of data can 32 MB of RAMstore?

b) How many bytes of data can a 3 GB harddrive store?

35. What are bits grouped in units of 16 to 64called?

36. When would an overflow error occur?

37. What are real numbers?

38. When would a roundoff error occur?

Sections 15 — 2539. What is a network?

40. List four benefits of using a network.

41. a) What are the two common size classificationsfor networks?

b) What size classification is used to connect de-vices over large geographical distances?

42. What is a network operating system?

43. a) What does network architecture refer to?b) List two common network architecture

models.

44. a) What does physical topology refer to?b) What is a node?c) Which topology uses a hub?d) Which topology connects each node to form

a closed loop?e) What is the difference between physical and

logical topology.

45. List three netiquette rules.

46. a) What is an intranet?b) What is an extranet?

47. What is the largest and most widely accessednetwork?

48. What is a router?

49. a) How does a client interact on the Internet?b) Why is the client/server structure called

interactive?

50. a) How can an individual get access to theInternet?

b) List an example of an online informationservice.

51. a) What is telecommunications?b) List three telecommunications options.

52. a) If a business needed constant access to theInternet, what type of connection line wouldbe a good choice? Why?

b) What does a cable modem use instead ofanalog phone lines?

53. What is the most widely used Internet service?

54. a) What is e-mail?b) List one benefit of e-mail over standard mail.

55. a) What is chatting?b) What is meant by real time?c) Why is chatting considered a real-time event.

56. What does a bulletin board service allow a userto participate in?

57. a) What is a listserv?b) What is HTTP used for?c) What is FTP used for?

58. Gopher locates information on the Internetusing what type of environment?

59. What is online profiling?

60. What is a cookie?

61. a) What is a Web beacon?b) Who usually monitors the information

collected by Web beacons?

62. What is a privacy policy?

63. Name and briefly describe one law that helpsprotect the privacy of an individual.

64. a) List three reasons why many schools havedeveloped an Acceptable Use Policy.

b) List an example of a rule that typicallyappears on an Acceptable Use Policy.


65. What is meant by the information age?

66. a) How do you believe society is benefittingfrom the information age?

b) What are some of the negative aspects of theinformation age?

67. How can computers be used to invade yourprivacy?

68. What can you do if you are turned down forcredit at a bank and believe that the data usedto deny credit is inaccurate?

69. a) What is necessary for a federal governmentauthority to access an individual’s financialrecords?

b) What must a financial institution do afterreleasing an individual’s records?

70. a) What is copyright infringement?b) What is computer piracy?c) What is a computer virus?d) What is a computer hacker?e) What is a firewall used for?

71. List four IT careers.

72. a) What are the responsibilities of aprogrammer?

b) What skills are required for Web developer?

73. a) What do ISPs provide?b) Which career includes setting up and

maintaining an intranet for a company ororganization?

74. What duties could be included for a networkadministrator?

75. a) What ethical responsibilities does an ITprofessional have when creating software?

b) Can an IT professional guarantee that dataretrieved is accurate? Why or why not?


Exercises

The exercises in this chapter require written information. If a word processor is used, be sure to usean appropriate header, footer, and file name.

Exercise 1 ��Expand on the information presented in this chapter by researching one of the following topics:

• Network Protocols• Operating Systems• The History of the Internet

a) Use the Internet, magazines, and books to find at least three sources of information.

b) Write a two page report that summarizes your research.

c) On a separate sheet, titled References, cite each source.

Exercise 2 ��In this exercise you will research your classroom computer network by answering a series ofquestions.

a) Is your computer network a LAN or a WAN?

b) List one device that is shared on the network.

c) Locate the cable that plugs into the network interface card on your workstation.

d) What type of physical topology is used?

e) What type of transmission media is used?

f) What network protocol is used?

g) What operating system is used?

h) What telecommunication option is used?

i) Does the school have an intranet?

j) List four rules on the school’s Internet Use Agreement.


Exercise 3 ��In this exercise you will further research emerging technologies and find real-life examples of howthese technologies have impacted individuals.

a) Use the Internet, magazines, and books to learn more about at least three emergingtechnologies. Look specifically for information on how these emerging technologiesimpact individuals. For example, speech recognition greatly impacts those individu-als who must rely on voice input rather than keyboard input for a PC.

b) Write a two-page report that summarizes the impact of and lists several functionsof the emerging technologies you have researched.


Exercise 4 ��In this exercise you will research and compare the advantages and cost of obtaining Internet accessthrough three different telecommunication options.

a) Use the Internet and newspapers to find information about ISPs.

b) Summarize the cost and compare the advantages of at least three different telecom-munication options.

c) Write a one paragraph conclusion that explains what telecommunication optionwould be the best choice.

d) On a separate sheet, titled References, cite each source.

Exercise 5 ��In this exercise you will research and compare the advantages and cost of obtaining Internet accessfor a business.

a) Use the Internet and newspapers to find information about ISPs.

b) Summarize the cost and compare the advantages of at least two ISPs that offer ac-cess for businesses. Include a list of features that will be necessary for businesses.



Exercise 6 ��In this exercise you will further research privacy issues to find real-life examples of how this issuehas impacted individuals.


b) Write a two-page report that summarizes your research.


Exercise 7 ��In this exercise you will research a social or ethical issue associated with computer use, such asidentify theft, piracy, or malicious code to find real-life examples of how these issues have impactedcompanies or individuals.


b) Write a two-page report that summarizes your research.



Index

10G Ethernet 1516-bit binary code 124GL 254GLs 8

AA-0 6Acceptable Use Policy 20access 6Ada 7adapter 16address bus 10, 12ADSL 17Advanced Research Projects Agency 16Aiken, Howard 3Altair 8ALU 9AMD 10Analytical Engine 2animation 24antivirus program 22AOL 16Apple computer 8architectural design 5ARPANET 16arrangement of the nodes 14article 18artwork 9assembler 6assembly language 6associate degree 23Atanasoff, John 4Atanasoff-Berry Computer 4Athlon XP 10author 25

BBabbage, Charles 2backbone 14back-end development 24Backus, John 6bandwidth 14Bardeen, John 6base 10 11base 16 12base 2 11, 12base unit 9BASIC 8batteries 10BBS 18Bell Laboratories 6, 7Berry, Clifford 4binary 12binary data 17binary number system 4, 11bit 11bits per second 14Bluetooth 10bps 14brain 10Brittain, Walter 6browser See Web browserbulletin board service 18bus 10, 14bus topology 14business administration 23business application 23Byron, Ada 2, 7byte 11


CC 7C# 8C++ 8C-10 5cable modem 17cabling 14cache 10cards 3CD-RW 9CD-RW/DVD drive 9cellular phone 11centralized software updates 13certification 22chat 18Children’s Online Privacy Protection Act 19chip 7cipher text 19circuit board 7, 9circuits 7classes, OOP 8client/server 14client/server structure 16clock 1clock rate 9coaxial cable 14coaxial cable television network 17COBOL 7code 19codes, encryption 5Colossus 5community college degree 23compiler 6, 8computercomputer defined 5computer engineer 23computer scientist 23computer teacher 24computer-related technology 22control bus 10conventional modem 17convertible 11cookie 19copyright 21copyright infringement 21Countess of Lovelace 2CPU 5, 8, 9, 10, 14cracker 22credit rating 20cross-platform connectivity 11

Ddata 20

destruction 21transmission rate 14

data bus 10database 8, 25database infrastructure 24data-entry operator 23debug 7decimal number system 11decimal points 13demodulation 17Department of Defense 16design 23desktop PC 9Difference Engine 2digital camera 11digital telephone network 17digitized image 9discussion group 18diskette drive 9drawings 9Dreamweaver 25DSL modem 17duplication of computer software 21

Eear bud 11Eckert, J. Presper 4EDSAC 5Education requirements for IT careers 22EDVAC 5electro-mechanical devices 3Electronic Communications Privacy Act 19, 22Electronic Freedom of Information Act 19electronic mail 18e-mail 13, 18, 22, 23encryption 19English-like instructions 6ENIAC 4, 8Ethernet LAN protocol 15ethical implications 20ethical responsibility 25etiquette 15exchange data 13expansion board 9exponent 13extranet 16


FFair Credit Reporting Act 21Fairchild Semiconductor 7Fast Ethernet 15fiber optic cable 14file backups 13file management 13Financial Privacy Act 21firewall 16, 22Fireworks 25first generation computers 5Flash 25floating point numbers 13Flowers, Tommy 5Fortran 6fourth-generation languages 8French philosopher 1front-end development 24FTP 18

GGB 12Gigabit Ethernet 15gigabytes 12gigahertz 9goggles 11gopher 18graphics 9

Hhacker 22HAN 13handheld calculator 7handheld PC 11handwriting recognition software 11hard disk 14hard disk drive 9, 14hardware 9hexadecimal system 12high school diploma 23high-level programming languages 6Hoff, Marcian 8Holberton, Betty 5Hollerith, Herman 3Home Area Network 13Hopper, Grace Murray 6, 7HTML 25HTTP 18hub 15human resources 23

IIBM 3IBM-PC 8IC 7illegal copy 21illegal use of data 21Illustrator 25information age 20information architecture 24Information Services 22Information Technology 22ink cartridge 9ink jet printer 9input devices 9integrated circuits 7Intel Corporation 7, 8, 10Intel Pentium 4 10interactive 16Internet 16, 22Internet access 11Internet browsing service 18Internet connections 21Internet service provider 16Internet Relay Chat 18Internet Use Agreement 20Internet worm 21interpreter 8intranet 16, 24intranet analyst 24IP address 19IRC 18IS 22ISDN 17ISDN terminal adapter 17ISP 16, 25IT 22IT professional 25IT professional ethics 25

JJacquard, Joseph 2Java 8Jobs, Steven 8

KK 12Kbps 16Kemeny, John 8key 19keyboard 5, 8, 9, 11keypad 5


Kilby, Jack 7kilo 12kilobytes 12Kurtz, Thomas 8

LLAN 14LAN manager 24laser 9laser printer 9Leased/Dedicated lines 17legally binding document 19Leibniz wheel 1Linux 14listserv 18LISTSERV 18log on to a network 15logical topology 15Lord Byron 2low-level language 6

MMac 14machine language 5, 6Macintosh 8macros 21Macs 8magnetic tape 6mailing list 18mainframe 7malicious code 21MAN 13Management Information Services 22manager 23mantissa 13manufacturer 23manufacturing worker 23Mark I 3Mark II 7Mauchly, John 4MB 12Mbps 16mechanical calculating devices 1megabytes 12megahertz 9memory 2, 10metallic oxide 7Metcalfe, Bob 15Metropolitan Area Network 13microcomputer 8microphone 11microprocessor 8

Microsoft Internet Explorer 17miniaturization 10MIS 22MIS department 23mobile computing devices 10Model 650 6modem 16, 17modulation 17monitor 8, 9monitoring 19moth 7motherboard 9mouse 9MP3 players 11multiple users 14

Nnanoseconds 9natural language processor 18, 23Navy 6netiquette 15network 13network administrator 24network architecture 14network interface card 14network news 18network operating system 14network security system 16network technologies 16networks 22Neumann, John von 5newsgroup 18node 14notebook PC 10Noyce, Robert 7

Oobject-oriented programming 8odometer 4Oikarinen, Jarkko 18online forums 23online information service 16online profiling 19OOP 8oral communication 22OS 11output devices 9overflow error 13


PP4 10pager 11Pascal, Blaise 1Pascaline 1password 15password protection 13PC 8, 9, 10-11PDA 11peer-to-peer 14peripheral devices 9phone lines 17photos 9PhotoShop 25piracy 21post 18, 25Presidential Medal of Technology 4printers 9privacy 19, 20Privacy Act of 1974 21privacy policy 19problem-solving skills 22professor 24program 5, 6, 8, 10, 11, 21programmer 2, 23, 25protection of digital information 21protocol 15punched cards 2, 6

RRAM 10, 14range restriction 14read 6READ 6real numbers 13real-time applications 7real-time event 18real-time information 25receiving data 16reel-to-reel tape machines 6reliability of the computer software 25remote log on 18removable hard disk drive 9replicate 21reproduction of data 21restrict access 13ring topology 15Ritchie, Dennis 7robot 23ROM 10roundoff error 13router 16

SSafety and Freedom through Encryption Act 19sales 24scanner 9scripts 21second generation computers 6security access features 14security options 13semiconductor 6server 16, 18, 25server computer 14sharing devices 13Shockley, William 6silicon 7slate 11social implications 20society 16software 10software updates 13specification 23spreadsheets 11SRAM 10star topology 15Stepped Reckoner 1storage media 10store 6stylus 11subscriber 18System 360 7system analyst 23

TT-1 carrier 17tablet PC 11Tabulating Machine Company 3tape drive 9TCP/IP 16teamwork 22technical knowledge 22technical school 23technical support technician 23technology coordinator 24telecommunications 16telephone relay switches 3Telnet 18terminal 8Texas Instruments 7think 2toner 9topology 14topology, logical 15transistor 6, 7


transistors 10transmission media 14transmit data 14transmitting data 16Trojan horse 21, 22Turing, Alan 5twisted-pair wiring 14

UU.S. Census 3U.S. Census Bureau 5unauthorized access 22unauthorized access to data 19unauthorized network access 16Unicode 12United States Department of Defense 7UNIVAC 5, 8universal machine 5Unix 14, 18URL 19USENET 18user name 15

Vvacuum tubes 4, 5vandalism 22video 16video adaptor 9virus 21Visual Basic .NET 8voice 16voice recognition 11

WWAIS 18WAN 14, 15wearable computer 11weaving looms 2Web 17, 22Web author 25Web beacon 19Web browser 17, 18Web bugs 19Web designer 25Web developer 24Web host 25Web server 18Web site 17, 24Webmaster 25Wilhelm von Leibniz, Gottfried 1

Windows 14wireless technology 10word 13word processors 11World War II 5World Wide Web 17worldwide network 16worm 22Wozniak, Stephen 8Wrist-top computers 11write 6WRITE 6writing skills 25written communication 22WWW 17

ZZip drive 9

An Introduction to Computers · An Introduction to Computers © 2003 Lawrenceville Press An Introduction to Computers 1 Mechanical Devices..... 1 2 Electro-Mechanical Devices .....

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