52488613 chapter 5 computer software and systems

8/7/2019 52488613 Chapter 5 Computer Software and Systems

1/40

COMPUTER SOFTWARECOMPUTER SOFTWAREAND SYSTEMSAND SYSTEMS


2/40

A. Computer SoftwareA. Computer Software

Software is the general term applied to theSoftware is the general term applied to theinstructions that direct the computersinstructions that direct the computershardware to perform workhardware to perform work

Software consists of instruction communicatedSoftware consists of instruction communicatedelectronically to the hardwareelectronically to the hardware

2 Purposes of the Software2 Purposes of the Software

1. It is needed to translate instructions created1. It is needed to translate instructions createdin human language to machine languagein human language to machine language2 . Packaged or stored software is needed to2 . Packaged or stored software is needed tomake the computer an economical work toolmake the computer an economical work tool


3/40

ProgramsPrograms -- organized instruction sets supplied toorganized instruction sets supplied tothe softwarethe software

PackagePackage a set of related programsa set of related programs


4/40

B . Brief History of Computer

Programming & Software1800 s1800 s idea of having computer programs stored on a hardidea of having computer programs stored on a hard

drive and brought into memory at the users commanddrive and brought into memory at the users command

A ugusta Ad a ByronA ugusta Ad a Byron first described the concept of a storedfirst described the concept of a storedcomputer programcomputer program

Charles BabbageCharles Babbage invented the analytical machineinvented the analytical machine

Countess LovelaceCountess Lovelace she theorized the loop concept, it isshe theorized the loop concept, it isthe use of automatic repetitious arithmetic steps to solve athe use of automatic repetitious arithmetic steps to solve aproblem; she is also the first programmer problem; she is also the first programmer


5/40

R obert Von NewmannR obert Von Newmann proposed that both data andproposed that both data and

instructions could be automatically carried oninstructions could be automatically carried on

Joseph Jacquar dJoseph Jacquar d invented the Jacquard Loom used toinvented the Jacquard Loom used toblocks of wood with holes drilled in such a way that theblocks of wood with holes drilled in such a way that thethreads to be woven into cloth could form a programthreads to be woven into cloth could form a program

H erman H ollerith ( 1884) H erman H ollerith ( 1884) developed a machine that coulddeveloped a machine that couldread punch cards and tabulate the resultsread punch cards and tabulate the results

Punch Car d Metho d Punch Car d Metho d existed until the late 19600 sexisted until the late 19600 swhile in many computer centers use the method untilwhile in many computer centers use the method untilaround 1980around 1980


6/40

R ear Ad miral Grace Murray H opperR ear Ad miral Grace Murray H opper the mother of the mother of computing because she developed many of the conceptscomputing because she developed many of the conceptsand mathematical foundations of computer programmingand mathematical foundations of computer programmingscience; worked with Mark I, the first digital Computer;science; worked with Mark I, the first digital Computer;also coined the term debugging also coined the term debugging

1950 s1950 s foundation of common businessfoundation of common business --oriented languageoriented language(COBOL) which is the first universal programming(COBOL) which is the first universal programminglanguage and first truly Englishlanguage and first truly English -- like languagelike language


7/40

B A SIC INPUT OUTPUT SYSTEM (BIOS ) B A SIC INPUT OUTPUT SYSTEM (BIOS ) the software onthe software onthe BIOS chip is the first part of the computer to function whenthe BIOS chip is the first part of the computer to function whenthe computer is turned onthe computer is turned on

OPE R A TING SYSTEMS (OS ) OPE R A TING SYSTEMS (OS ) are the actual software loadedare the actual software loadedfrom the hard rive into RAM as soon as the computer is turnedfrom the hard rive into RAM as soon as the computer is turnedonon

C. Types of Software

1. System Software boots up the computer system(starts up and initializes); controls input, output andstorage; and controls the operations of the applicationsoftware


8/40

USE R INTE RF A CESUSE R INTE RF A CES

a . Disk Operating System (DOS OS ) a . Disk Operating System (DOS OS ) designed fordesigned formainframe computers and replicated the proceduresmainframe computers and replicated the proceduresprogrammers used under manual OSsprogrammers used under manual OSs

b . Graphical User Interface (GUI ) b . Graphical User Interface (GUI ) the computer forthe computer for

everybody, Macintosh everybody, Macintosh

2 . A pplications Software2 . A pplications Software support the actual wok of support the actual wok of the user; includes the various programs people use tothe user; includes the various programs people use todo work process data, play games, communicate withdo work process data, play games, communicate with

others, or watch multimedia programsothers, or watch multimedia programs


9/40

3 . Utility Programs3 . Utility Programs used to help maintain the system,used to help maintain the system,clean up unwanted programs, protect the system againstclean up unwanted programs, protect the system againstvarious attacks, access the World Wide Web (WWW), andvarious attacks, access the World Wide Web (WWW), and

the likethe like-- designed to enhance the functions of the OS or perhaps todesigned to enhance the functions of the OS or perhaps to

add facilities that the basic OS does not offeradd facilities that the basic OS does not offer

Language Translation UtilitiesLanguage Translation Utilities translation programstranslation programsare needed to convert instructions written in an Englishare needed to convert instructions written in an English --like language into binary . These types of translationlike language into binary . These types of translationprograms are calledprograms are called assemblers, compilers, orassemblers, compilers, orinterpretersinterpreters

The Worl d Wi d e Web an d Web BrowsersThe Worl d Wi d e Web an d Web Browsers WWWWWWprovides a protocol for document transfer across theprovides a protocol for document transfer across theinternet; ainternet; a Web BrowserWeb Browser is a utility program thatis a utility program thatallows the user to access the web and the materialsallows the user to access the web and the materialsavailable through the webavailable through the web


10/40

Programming LanguagesProgramming Languages means of communicating withmeans of communicating withthe computerthe computer

Generations an d Levels of Programming LanguagesGenerations an d Levels of Programming Languages Divided into 5 generations, or in sometimes at 3 levelsDivided into 5 generations, or in sometimes at 3 levels Level refers to how close the language is to the actualLevel refers to how close the language is to the actual

machinemachine

1. First Level (includes the first 2 generations of 1. First Level (includes the first 2 generations of programming: machine language and assembly language)programming: machine language and assembly language)

2 . Second Level (includes high2 . Second Level (includes high -- level procedural andlevel procedural andnonprocedural languages)nonprocedural languages)

3 . Third Level (includes natural language; also the 5th3 . Third Level (includes natural language; also the 5thgeneration)generation)


11/40

Machine LanguageMachine Language true language of thetrue language of thecomputercomputer

A ssembler LanguageA ssembler Language far more Englishfar more English -- like, butlike, butstill very close to machine languagestill very close to machine language

Thir d Generation LanguagesThir d Generation Languages include theinclude theprocedural and nonprocedural languages and wereprocedural and nonprocedural languages and werethe beginning of the second level in programmingthe beginning of the second level in programminglanguageslanguages ; ; the style and sequence of a languagethe style and sequence of a language

are called syntax are called syntax

F ourth Generation LanguagesF ourth Generation Languages specialized applicationspecialized applicationprograms that require more involvement of the user in directingprograms that require more involvement of the user in directingthe program to do necessary workthe program to do necessary work

F ifth Generation LanguagesF ifth Generation Languages or third level languages areor third level languages arealso called natural language; user tells the machine what to do inalso called natural language; user tells the machine what to do inthe users own natural language or through the use of a set of athe users own natural language or through the use of a set of avery Englishvery English -- like commandslike commands

Visual Programming LanguagesVisual Programming Languages facilitate programfacilitate programdevelopment in graphicsdevelopment in graphics --based environmentsbased environments


12/40

D. Common SoftwareD. Common Software

Packages forPackages forMicrocomputersMicrocomputers

Stan d ar d Office PackageStan d ar d Office Package -- most common package soldmost common package soldwith computers; includes a wordwith computers; includes a word --processing program, aprocessing program, aspreadsheet, a presentation graphics program, and somespreadsheet, a presentation graphics program, and someform of dataform of data --base management systembase management system

2 Most Commonly Used Programs2 Most Commonly Used Programs1. E1. E--mail Systemsmail Systems2 . Word Processor2 . Word Processor


13/40

E. Software PackageE. Software Package

Ownership RightsOwnership RightsThe software industry has followed an ownership modelThe software industry has followed an ownership modelmore similar to that of the book publishing industry, inmore similar to that of the book publishing industry, inorder to avert users not to distribute the programsorder to avert users not to distribute the programs

When a commercial product is sold, the buyer can not useWhen a commercial product is sold, the buyer can not usethe product or resell it or loan it to a friend if so desiredthe product or resell it or loan it to a friend if so desired

Copying the product is not feasibleCopying the product is not feasible

Any other installations, apart from the original purchasers,Any other installations, apart from the original purchasers,

were considered illegalwere considered illegal

An exception can be made if the purchaser has both aAn exception can be made if the purchaser has both adesktop and a laptop, fair use allow him to installdesktop and a laptop, fair use allow him to installprograms on all the machines he owns, so long as theprograms on all the machines he owns, so long as thecomputers are for his personal use onlycomputers are for his personal use only


14/40

Companies that have multiple computers that are used byCompanies that have multiple computers that are used bymany employees must purchase a separate copy for eachmany employees must purchase a separate copy for eachmachine, or purchase a site license (a way of buying inmachine, or purchase a site license (a way of buying inbulk or so to speak)bulk or so to speak)

What is not permitted, in fact a from of theft, is to installWhat is not permitted, in fact a from of theft, is to installmore copies of the software than were paid formore copies of the software than were paid for


15/40

F. Common Software Useful toF. Common Software Useful to

NursesNursesSoftware used by nurses includesSoftware used by nurses includes a d mission, d ischarge,a d mission, d ischarge,an d transfer ( A DTan d transfer ( A DT ) systems that help with patient) systems that help with patienttracking, andtracking, and me d ication a d ministration recor d (M A R me d ication a d ministration recor d (M A R ))softwaresoftware

Computer Physician Or d er Entry (CPOE )Computer Physician Or d er Entry (CPOE ) is alsois alsoconsidered, a system to be so important that they list it asconsidered, a system to be so important that they list it asa separate item on their quality checklista separate item on their quality checklist

Chat R oomsChat R ooms are like electronic conference callsare like electronic conference calls

Electronic Bulletin Boar d sElectronic Bulletin Boar d s creates space where userscreates space where userscan post a messagecan post a message

List ServersList Servers the least powerful version of an electronicthe least powerful version of an electronicbulletin boardbulletin board


16/40

G . Computer ProgrammingG . Computer ProgrammingRefers to the process of writing a computer program,Refers to the process of writing a computer program,which is a series of instructions written in properwhich is a series of instructions written in propersequence to solve a problemsequence to solve a problem

5 Major Steps5 Major StepsProblem Definition (functional specificationsProblem Definition (functional specificationsProgram DesignProgram DesignWriting the Code and Program DocumentationWriting the Code and Program DocumentationAlpha TestingAlpha Testing

Beta Testing and Program DocumentationBeta Testing and Program Documentation

Problem or F unctions SpecificationProblem or F unctions Specification requires that therequires that theproblem or task be very precisely defined and theproblem or task be very precisely defined and theprocedures to be performed by the program be perfectlyprocedures to be performed by the program be perfectlymisunderstood into the programming language to be usedmisunderstood into the programming language to be used


17/40

Program Design SpecificationsProgram Design Specifications2 Types of specifications2 Types of specifications

1. Set of functional specifications that identifies all the1. Set of functional specifications that identifies all thefunctions thefunctions theprogram is to performprogram is to perform2 . (SPECS) Design specs2 . (SPECS) Design specs instructions given to theinstructions given to theprogrammerprogrammer

Program PreparationProgram Preparation -- the actual writing (coding) of thethe actual writing (coding) of theprogram, entails translating the design specifications intoprogram, entails translating the design specifications intothe programming language to be usedthe programming language to be used

DocumentationDocumentation

2 Types of Documentation that Must be Pro d uce d2 Types of Documentation that Must be Pro d uce d1. The program itself should be designed in a highly1. The program itself should be designed in a highlystructured, topstructured, top --down manner, and the lines of the codedown manner, and the lines of the codeshould be liberally sprinkled with explanatory statementsshould be liberally sprinkled with explanatory statements


18/40

2 . Users Manual2 . Users Manual provides clear directions and examples of provides clear directions and examples of how to makehow to makethe program work as intendedthe program work as intended

Program TestingProgram Testing

A lpha TestingA lpha Testing also called desk checking, its purpose isalso called desk checking, its purpose isto see if all the processes appear to be functioning asto see if all the processes appear to be functioning asspecified in the flow charts, functional specifications, andspecified in the flow charts, functional specifications, anddesign specsdesign specsBeta TestingBeta Testing the program is installed in the actual userthe program is installed in the actual userenvironment, and further programming of screen formats andenvironment, and further programming of screen formats andother user interface functions is performedother user interface functions is performed

Program ImplementationProgram Implementation the final step in programming;the final step in programming;the program is implemented throughout the beta sitethe program is implemented throughout the beta site


19/40

H. Computer SystemsH. Computer Systems

It is a complex entity, consisting of an organizedIt is a complex entity, consisting of an organizedset of interconnected components or factors thatset of interconnected components or factors thatfunction together as a unit to accomplish resultsfunction together as a unit to accomplish resultsthat one part alone could notthat one part alone could not


20/40

I. Systems TheoryI. Systems TheoryProvides the conceptual basis for understanding complexProvides the conceptual basis for understanding complexentities that consist of multiple interrelated parts workingentities that consist of multiple interrelated parts workingtogether to achieve a desired result . Such entities are calledtogether to achieve a desired result . Such entities are called

systemssystems

Primary Propositions of the TheoryPrimary Propositions of the Theory

1. A system takes in input on which to perform processes1. A system takes in input on which to perform processes

2 . The processes performed by a system on input result in2 . The processes performed by a system on input result insystem outputsystem output

3 . The processes in a system are subject to control forces3 . The processes in a system are subject to control forces

4 . Feedback is the key mechanism of control in a system4 . Feedback is the key mechanism of control in a system


21/40

5 . A systems parts interact in such a way that the parts are5 . A systems parts interact in such a way that the parts areinterdependent with the respect to the systems processesinterdependent with the respect to the systems processes

6. Impingement on one part in a system will produce effects on6. Impingement on one part in a system will produce effects onthe systems processes and may produce distortions on thethe systems processes and may produce distortions on theother parts of the system . A corollary to this proposition isother parts of the system . A corollary to this proposition isthe followingthe following

7 . Distortion in one part of a system may be a symptom of a7 . Distortion in one part of a system may be a symptom of aproblem in another component (Secondary Malfunction)problem in another component (Secondary Malfunction)

8. Thus, correction of a malfunctioning part will correct the8. Thus, correction of a malfunctioning part will correct thesystem functioning only if the malfunction was a primarysystem functioning only if the malfunction was a primarymalfunction and not a secondary malfunctionmalfunction and not a secondary malfunction

9. Effects on the systems processing function will affect the9. Effects on the systems processing function will affect thesystems outputsystems output


22/40

10. A system is more than the sum of its parts . Thus, while a10. A system is more than the sum of its parts . Thus, while asystem can be broken down into its component parts, if thissystem can be broken down into its component parts, if thisis done, the system no longer exists . Corollaries to thisis done, the system no longer exists . Corollaries to thisproposition are the following:proposition are the following:

(a) The functioning of a system is different than the(a) The functioning of a system is different than thefunctioning of its partsfunctioning of its parts

(b) The output of each separate part, even if combined,(b) The output of each separate part, even if combined,does not equal the output of the systemdoes not equal the output of the system

(c) When combined into a system, the component parts(c) When combined into a system, the component partsform an entirely new entityform an entirely new entity


23/40

J . System ElementsJ . System Elements1. Inter d epen d ent Parts1. Inter d epen d ent Parts the most defining attribute of athe most defining attribute of a

system is that its parts interact to conduct some processsystem is that its parts interact to conduct some process

2 . Input2 . Input is any factor from the external environment that isis any factor from the external environment that istaken into the systemtaken into the system

3 . Process3 . Process the activity of the systemthe activity of the system

4. Output4. Output any product or waste produced as a result of any product or waste produced as a result of system processsystem process

5. Control5. Control refers to any component or activity that serves torefers to any component or activity that serves toprevent or correct problems or errors in the systems input,prevent or correct problems or errors in the systems input,process, outputprocess, output

6 . F ee d back6 . F ee d back is output from one part of a system process thatis output from one part of a system process thatserves as input to another part of a system processserves as input to another part of a system process


24/40

K . Classification of SystemsK . Classification of Systems

Close d SystemsClose d Systems a system with the followinga system with the followingcharacteristics: differentiation, isolation, independence,characteristics: differentiation, isolation, independence,and self and self -- sufficiency (self sufficiency (self --containment or self containment or self -- regulation)regulation)

Open SystemsOpen Systems systems that exhibit integration, fluidsystems that exhibit integration, fluidor fuzzy boundaries, and interaction with theiror fuzzy boundaries, and interaction with theirenvironments (Markas, 2 00 2)environments (Markas, 2 00 2)


25/40

F igure 5.8

Open System Interactions

CDCinfectiousdisease

database

State healthoutcomes

database &benchmark file

Post-surgical

infections inhospital

database

CDC co-fundeduniversity study of

incidence of infections in5-state region

Hospitalconsortium

database


26/40

IV CPU

M easure bloodpressure every 30

minutes

Administer ordereddose of

antihypertensive

BP toohigh

No

Yes

F igure 5.7Closed system with feedback loop


27/40

L. Computer SystemsL. Computer Systems

Used to describe the set of Used to describe the set of

peripherals, computer box,peripherals, computer box,and software that togetherand software that togetherperform computing functionsperform computing functionsfor one or more usersfor one or more users


28/40

M. Information SystemsM. Information SystemsThe collection and integration of various pieces of hardwareThe collection and integration of various pieces of hardwareand software and the human resources that meet the dataand software and the human resources that meet the datacollection, storage, processing, and report generation needscollection, storage, processing, and report generation needsof an organizationof an organization

Information System TypesInformation System Types1. Management Information Systems1. Management Information Systems an organizedan organizedsystem for managing the flow of information in ansystem for managing the flow of information in anorganization in a timely mannerorganization in a timely manner

2 . Bibliographic R etrieval Systems2 . Bibliographic R etrieval Systems a retrieval systema retrieval systemthat generally refers to bibliographic data, documentthat generally refers to bibliographic data, documentinformation, or literatureinformation, or literature

3 . Stan d3 . Stan d--A lone, d e d icate d , or Turnkey SystemsA lone, d e d icate d , or Turnkey Systems developed for a single application or set of functionsdeveloped for a single application or set of functions


29/40

4. Transaction Systems4. Transaction Systems used to process predefinedused to process predefinedtransactions and produce predefined reportstransactions and produce predefined reports

55 . . Physiologic Monitoring SystemsPhysiologic Monitoring Systems are being used moreare being used morefrequently to measure and monitor continuous automaticfrequently to measure and monitor continuous automaticphysiologic findings; provide alarms to detect significantphysiologic findings; provide alarms to detect significantabnormal findings when personnel are needed to provideabnormal findings when personnel are needed to providepatient care and save livespatient care and save lives

66 . . Decision Support SystemsDecision Support Systems support some aspect of thesupport some aspect of the

human decisionhuman decision--making processmaking process

77 . . Expert SystemsExpert Systems contain the information and decisioncontain the information and decision --making strategies of an expert to assist nonmaking strategies of an expert to assist non --experts inexperts indecisiondecision --making (Marakas, 2 00 3); designed for users tomaking (Marakas, 2 00 3); designed for users tostimulate the cause and effect reasoning that an expert wouldstimulate the cause and effect reasoning that an expert woulduse if fronted with the same situation in a real live environmentuse if fronted with the same situation in a real live environment


30/40

88 . . A rtificial Intelligence SystemsA rtificial Intelligence Systems (AI System) attempts(AI System) attemptsto model human reasoning processesto model human reasoning processes

99 . . Natural Language SystemsNatural Language Systems can understand andcan understand andprocess commands given in the users own natural, spokenprocess commands given in the users own natural, spokenlanguagelanguage


31/40

N. Hospital InformationN. Hospital Information

Systems (HIS)Systems (H

IS)

Sometimes called aSometimes called a me d icalme d icalinformation system (MIS ) information system (MIS ) ororpatient care system (PCSpatient care system (PCS ),),provides support for a wideprovides support for a widerange of both administrativerange of both administrativeand clinical functions; theand clinical functions; thepurpose of anpurpose of an H ISH IS is to manageis to manageinformation needed to facilitateinformation needed to facilitate

daily hospital operations by alldaily hospital operations by allhealth care personnelhealth care personnel


32/40

H IS ConfigurationsH IS Configurations the most common configuration uses athe most common configuration uses amainframe computer with hardwired terminals or workstationsmainframe computer with hardwired terminals or workstations

Program Mo d ules A vailable in H ISProgram Mo d ules A vailable in H IS include a wide variety of include a wide variety of administrative applications (modules) such as admission andadministrative applications (modules) such as admission anddischarge, patient tracking, finance, payroll, billing, budgetingdischarge, patient tracking, finance, payroll, billing, budgetingsupport, inventory, and management reporting programssupport, inventory, and management reporting programs

Semiclinical Mo d ulesSemiclinical Mo d ules

2 Mo d ules2 Mo d ules

1. A DT1. A DT --module monitors and sometimes controls the flow of module monitors and sometimes controls the flow of patients in a hospital from admission to dischargepatients in a hospital from admission to discharge

2 . OE2 . OE the orderthe order --entryentry -- resultsresults -- reporting module; order entryreporting module; order entrymeans that staff can enter laboratory, pharmacy, and radiologymeans that staff can enter laboratory, pharmacy, and radiologyorders online; means that the lab, pharmacy, and radiology canorders online; means that the lab, pharmacy, and radiology canenter the results in a computer system and have those availableenter the results in a computer system and have those availableto the nursing unitto the nursing unit


33/40

Clinical Support Mo d ulesClinical Support Mo d ulesCharting SystemsCharting Systems includes medical administrationincludes medical administration

reports, admission assessments, special assessments, atreports, admission assessments, special assessments, atleast some elements of nursing care plan, vital signsleast some elements of nursing care plan, vital signsrecords, wound care, and hygienic care recordsrecords, wound care, and hygienic care records

PointPoint -- of of -- Service Systems (POS ) Service Systems (POS ) uses a handuses a hand --held orheld orbedside PC to ensure that data are entered at the point atbedside PC to ensure that data are entered at the point atwhich they are collectedwhich they are collected

Laboratory, Pharmacy, an d R a d iology Mo d ulesLaboratory, Pharmacy, an d R a d iology Mo d ules tracks the specimen through various laboratory stages,tracks the specimen through various laboratory stages,generates the results, and communicates the findings togenerates the results, and communicates the findings topatients medical record; tracks medication orders andpatients medical record; tracks medication orders andchanges in orders; separate products developed bychanges in orders; separate products developed bycompanies that specialize in diagnostic computer imagingcompanies that specialize in diagnostic computer imagingsystemssystems


34/40

O. Network SystemsO. Network Systems

A network is a set of A network is a set of

interconnected computers that,interconnected computers that,through hardware and softwarethrough hardware and softwaretechnology, work cooperativelytechnology, work cooperatively

for the purpose of informationfor the purpose of informationand application programand application program

interchangeinterchange


35/40

2 Essential F actors for A ny Network2 Essential F actors for A ny Network HardwareHardware Network Communication SoftwareNetwork Communication Software

Ad vantages to CompaniesAd vantages to Companies1. Efficiencies Related to Storage and Data Integrity1. Efficiencies Related to Storage and Data Integrity2 . Software Savings2 . Software Savings3 . Savings in Human Time and Efficiency3 . Savings in Human Time and Efficiency


36/40

Network F unctionsNetwork F unctions1. File transfer1. File transfer2 . Information availability2 . Information availability

3 . Resource sharing3 . Resource sharing4 . Online transaction4 . Online transaction5 . Provision of a powerful communication medium5 . Provision of a powerful communication medium6. Interactive environment6. Interactive environment7 . Education and Entertainment7 . Education and Entertainment8. E8. E--mailmail

Network SecurityNetwork Security

Vacuum TubesVacuum Tubes were vulnerable to heat and dirt . were vulnerable to heat and dirt . Therefore, mainframe computer systems required a closed,Therefore, mainframe computer systems required a closed,airair --conditioned environmentconditioned environment

Electronic securityElectronic security is even more importantis even more important


37/40

Passwor d protectionPasswor d protection can be enough security for mostcan be enough security for mostsystems, provided that people give their passwords thesystems, provided that people give their passwords theproper handling and respectproper handling and respect

F irewallsF irewalls are specialized routers that carefully inspectare specialized routers that carefully inspecteach incoming packets of informationeach incoming packets of information

EncryptionEncryption , another layer of protection,, another layer of protection, means that themeans that thedata are converted into a cipher, or a code of some kinddata are converted into a cipher, or a code of some kind

Types of NetworksTypes of Networks

1. Local A rea Network (L A N )1. Local A rea Network (L A N ) a data networka data networkintended to serve a single building or a group of buildingsintended to serve a single building or a group of buildingsin close proximity to each otherin close proximity to each other

2 . Wi d e A rea Network (W A N )2 . Wi d e A rea Network (W A N ) system of connectedsystem of connectedcomputers spanning a large geographical area, often acomputers spanning a large geographical area, often acontinent or countrycontinent or country


38/40

Popular Search EnginesPopular Search Engines1. Altavista1. Altavista

2 . Yahoo!2 . Yahoo!3 . Google3 . Google

4.

37.com4

.37

.com5 . Go2net5 . Go2net

Navigating the Internet:Navigating the Internet: In order to enterIn order to enterthe Internet, the user must have an Internetthe Internet, the user must have an InternetService Provider (ISP) and a Web BrowserService Provider (ISP) and a Web Browser

3 . The Internet3 . The Internet is a network of networksis a network of networks


39/40

Web BrowserWeb Browser is a program that is used to visit Webis a program that is used to visit Webpages; it works by using a special protocol calledpages; it works by using a special protocol called H TTPH TTP

Worl d Wi d e WebWorl d Wi d e Web is a hypertextis a hypertext --based, subset of thebased, subset of theInternet that uses a combination of text, graphics, audio,Internet that uses a combination of text, graphics, audio,and video to provide information on almost every subjectand video to provide information on almost every subjectimaginableimaginable

H ypertext Markup LanguageH ypertext Markup Language the language used tothe language used tocreate hypertext documentscreate hypertext documents

Hypertext an

d H

yperlinksH

ypertext and

H

yperlinks hypertext is a document,hypertext is a document,written inwritten in H TMLH TML , which contains automated links, which contains automated links(hyperlinks) to other documents, which may or may not also(hyperlinks) to other documents, which may or may not alsobe hypertext documentsbe hypertext documents


40/40

THE ENDTHE ENDPRESENTED BY:PRESENTED BY:RALPH P. LLANES JR., S.NRALPH P. LLANES JR., S.N

BSN IIBSN II--11SUMMER 2009SUMMER 2009- -20102010

52488613 chapter 5 computer software and systems

Documents