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ManagingSystems

Development

December4,2014

Definitions

OfftheShelfsoftware

Standard(notcustom)softwareapplicationsthatcanbepurchasedfromcomputerstore.

Customsoftware

Tailormadesoftwarespeciallydevelopedtomeetaspecificorganization'sneedsandrequirements.

Inhousesystemdevelopment

DevelopingsoftwareapplicationsusinginternalITstaff

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Openingcase

Acompanyspecializedinrecyclingnuclearmaterial

1000+techniciansneedtouseasoftwareprogramforenteringandprocessingdatain

order

to

generate

technical

reports Offtheshelfsoftwarenotavailable

ThecompanyhasanITstaffwithtechnicalknowledgebutneedanexperiencedITconsultanttohelpdevelopacustommadesystem.

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Openingcase:Question Wheredoyoustart?Whatarethefewthings

thatneededtobedonetostarttheprocess?

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LEARNINGGOALS

ExplainthepurposeofsystemsdevelopmentmethodologiesSDM.

DiscussthemajorphasesofthetraditionalSystemsDevelopmentLifeCycle(SDLC)methodology.

DiscussAlternativeSDM

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SystemsDevelopmentMethodology?

Theprocesscompaniesgothroughtodevelopandmaintainaninformationsystem

FrameworkforsuccessfulISdevelopment

A

System

Development

Methodology

is

used

Forbuildinganewsystem

Orformodifyinganexistingsystem

ExamplesofSDM:

SystemDevelopmentLifeCycle - Prototyping

JointApplicationDevelopment - Rapid Application Development

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SystemsDevelopmentMethodology?

Theprocesscompaniesgothroughtodevelopandmaintainaninformationsystem

Frameworkfor

successful

IS

development

ASystemDevelopmentMethodologyisused

Forbuildinganewsystem

Orformodifyinganexistingsystem

ExamplesofSDM:

SystemDevelopmentLifeCycle - Prototyping

JointApplicationDevelopment - Rapid Application Development

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Questions WhichofthefollowingistrueaboutSDM?

a) TheyprovideguidelinesfordevelopingISandmaintainingthemwhich

includesupgradingandimprovingthem.

b) SDMareneededwhenabrandnewIShastobedeveloped,butyou

dontneedtouseaSDMwhenitcomestomodifyinganexistingIS.

c) W he nacompanyisengagedindevelopinganIS,theprocessinvolves

thecompanysemployeeswhowouldbethepotentialusersoftheIS,

andISprofessionalslikesystemanalystsandprogrammers. Butit

doesntinvolvethecompanysmanagement

d ) A lloftheabove

TraditionalSystemsDevelopmentLifeCycle(SDLC)

Sevenphases1) Planning 5) Testing

2) SystemsAnalysis 6) Implementation

3) SystemsDesign 7) Maintenance

4) Development

Typicallyonephaseneedstobe

completedbeforebeginningthenext

Probleminlaterphasemayrequire

returntopreviousphase

Planning

Analysis

Design

Development

Testing

Implementation

Maintenance

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Questions InSDLC,the7phasesaretypicallyfollowedina

sequentialorder,whichmeanswedontreturn

toapreviousphaseinanycircumstances

True False

DuringtheImplementationphaseoftheSDLC,

theDevelopmentteamencounterssomeserious

problems.Whichofthefollowingphasesmaybe

theculprit?

Planning Design Testing

Analysis Development Maintenance

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Planning

Feasibilityanalyses TechnicalAnalysis

Dothetechnologiesexisttodevelopthesystem?

EconomicAnalysis

Cantheorganizationaffordthesystem?

WillitprovideanadequateBenefit?

OperationalAnalysis(i.e.assessingthehumanfactorsthatcouldmaketheprojectfail)

Resistancetochange

Organizationalpolitics

Systemdevelopmentschedule Istheproposeddevelopmenttimelinerealistic?

IstheprogrammingteamavailableduringProgrammingstep?

PlanningperformedbyProjectManagerusing Searchandinvestigation(e.g.fortechnicalanalysisstep)

TotalCostofOwnershipanalysis

ProjectManagement

software

Feasibility Analyses

System Development Schedule

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SystemsAnalysis

Systemsanalystworkswithcompanytofullyunderstand

theproblem,andtodetailtherequirementsofthe

proposedsystem

Step1:

Analyze

current

system

Objectives:

Understandwhatthingsaredoneandhow(businessprocesses)

Identifyanyproblemsassociatedw/currentbusinessprocesses

Techniquesused:

Talkingtoemployees(potentialusers)

Conductinginterviews

Observingemployeesatwork

Analyze current system

Define new system requirements

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SystemsAnalysis

Step2:Definenewsystemsrequirements MainObjective:

Specify

What

need

to

be

done

(not

how

to

do

it) Tobedefined:

Inputrequirements(natureofdata,source,etc.)

Processingrequirements

Outputrequirements(Typesofreports,content,etc.)

Storagerequirements

Toolsandtechniquesused: Dataflowdiagrams(DFD)

Startwithhighlevelprocess

Addmorelevelswithincreasedlevelsofdetail

ComputerAidedSoftwareEngineering(CASE)tools

Softwarethateasesthesystemsdevelopment process

Analyze current system

Define new system requirements

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Questions DuringwhatSDLCphasesoftwareprogramslike

MicrosoftProjectcouldbeused?a) Maintenance

b) Implementation

c) Development

d) SystemAnalysis

e) Planning

f) Noneoftheabove

WhichofthefollowingtoolsortechniquescouldbeusedduringtheSystemAnalysisphaseoftheSDLC?(Chooseallcorrectanswers)

a) Interviews

b) Observingfutureusersdoingtheirjob

c) Usingpseudocode

d) Usingsoftware

programs

to

draw

data

flow

diagrams

e) Alloftheabove14

Questions Whatkindoffeasibilityanalysisseekstodetermineifan

organizationcanaffordthenewinformationsystemandifthesystemwillprovidetheadequatebenefits?

a) OperationalFeasibility

b) FinancialFeasibility

c) EconomicFeasibility

d) BeneficialFeasibility

e) Noneoftheabove

DuringtheDevelopmentphaseofanewmedicalIS,thedevelopmentteamfindsoutthatmostofthetechnologiesneededtodevelopandimplementthesystemarenotyetavailableonthemarket.AtwhatstepoftheSDLCthatkindofproblemshouldhavebeenidentified?

a) Maintenance

b) Implementation

c) Development

d) SystemAnalysis

e) Planning

f) Noneoftheabove15

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DataFlowDiagrams(DFD)

Data flow

Process

External Entity

Data storage

. Symbolized by an arrow.

. Shows data being passed from or to a process

. Symbolized by a rectangle or a curved rectangle.

. Action performed by people of organizationalunits in order to transform input into output ORAction performed by people in the organizationalunits to help the units achieve their objectives

Symbolized by a square, an external entity issomething (person, group, department, etc.)outside the system that interacts with the systemby providing input or receiving information.

Used to store data in the system.Represents a file, a database, etc.

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Exercise1:DFD

UseDataFlowDiagramtoillustrateyourschools

registrationsystem.AssumethatStudentsare

externalentities.Alsoassumethatthethree

processesinvolvedincourseregistrationare:

VerifyCourseavailability: afterreceivingacourserequest

fromastudent.ThisinvolvescheckingtheCoursefile

Enrollthestudent: inthecourseafterverifyingcourse

availability.ThisinvolvesupdatingtheStudentfile.

Confirmregistration. Thisinvolveswritinganconfirmation

letterandsendingittothestudent

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Exercise2:DFD

DotheLincolnPizzasorderingsystemDFD

exerciseavailableat:

http://www.eiu.edu/~a_illia/MBA5670/DFDExerci

se.htm

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SystemsDesign UsingtherequirementsfromtheSystemsAnalysisphasetodesign

thenewormodifiedsystem.

Logicalsystemsdesign

Detailsthe

systems

functionality

(what

it

should

do?)

UsesStructurechartstocreatetopdownrepresentation ofsystemsmodules

UsesSystemflowchartstoshowrelationshipsbetweenmodules

Physicalsystemsdesign

Specifiesalloftheactualcomponents (hardware, network,databases) usedtoimplementthelogicaldesign

Thedesignmustbefrozenatendofthisphasetopreventthesystemfromgrowingindefinitelyintermsofitsscopeandfeatures

Scopecreep(continuousgrowthinaproject'sscope)

Featurescreepcontinuous growthinaproject'sfeatures)

Performedbysystemdesigneror(systemanalystinsomecase)

Logical system design

Physical system design

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Development

Programmingisusuallythemostdifficultand

timeconsumingintheDevelopmentphase.

Developmentperformedbyprogrammers,

databasedevelopers,andnetworkengineers

ProgrammersuseProgramDevelopmentCycle1) Reviewtheinput,processing,output,andstoragerequirements

2) Developthelogicoftheprograms(usingFlowchartsandPseudocode)

3) Writetheprogramsusingcodegenerators &programminglanguages

4) Testanddebugtheprograms

5) Completetheprogramsdocumentation

Writing programs

Implementing networks components

Creating databases

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Developmenttools

Program Flowchart:

Graphical illustration of

the problem-solving logic

within a programPseudocode:

English-language

statements that describe

the processing steps of a

program in paragraph

form.

Programming languages:

-Java

-C++

-Visual Basic

-Etc.

Code generators:

Software thatgenerate programsthat programmerscould modify.

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Questions DuringwhatphaseoftheSDLCtheDatabase

componentofanewsystemiscreated?a) Maintenance

b) Implementation

c) Development

d) SystemAnalysis

e) Planning

f) Noneoftheabove

DuringwhatphaseoftheSDLCcodegeneratorscouldbeused?

a) Maintenance

b) Implementation

c) Development

d) SystemAnalysis

e) Planning

f) Noneoftheabove22

Testing

Programmerstestmodules Dotheyreturnproperoutputs?

Dotheyhandleincorrectdataappropriately?

Developmentteamdounit testing

i.e.testinghowmodulesworktogether

Systemtesting(softwarealongwithdatabaseandnetworkcomponent)

Verification:Testingsysteminsimulated

environmentwithsimulateddata

Validation:Testingsysteminrealworking

environmentwith

real

data

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Implementation

Implementationstrategies

Directcutover:Quickchangetonewsystem

Parallelconversion:Oldandnewsystemsusedin

parallelfor

awhile.

Pilottesting:Newsysteminstalledatonlyone

locationoronedepartment

Stagedconversion:Onlyonepartofthesystem

installed,thenanotherpartisinstalled.

Usertraining

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Maintenance

Maintenancecountsforasmuchas80%of

thetotal

cost

of

an

information

system

Tasks

Correctingerrorsfoundduringimplementation

Systemenhancements

Incrementalupgrades

Additionofmajornewfeatures

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Questions Theimplementationstrategyinwhichtheold

systemisimmediatelyreplacedbythenewoneiscalled:

a) Stagedconversion

b) Directcutover

c) Systematictesting

d) Noneoftheabove

ValidationtestingperformedduringtheTestingphaseoftheSDLCensuresthatthesystemisworkingproperlyintherealworkingenvironmentusingrealdata.

a) Trueb) False 26

SDLC:Recap

Steps Keyactors Tools/Techniques

1.Planning ProjectManager TCO,ProjectManagementsoftware

2.SystemA nal ys is S yst emAnalyst,Users. Interviews,observingusersatwork,

DFD

3.SystemDesign Systemanalyst(orsystemdesigner) SystemFlowchart,Structurechart

4.D ev el op me nt P ro gr am me rs ,databasedevelopers,

networkengineers

ProgramFlowchart, Pseudocode,

programminglanguages

5.Testing Developmentteam,Users Modulestesting,unitstesting,

Systems testing(verification,

validation)

6.Implementa tion D ev elopmentteam,Users Directcutover,parallelconversion,

pilottesting,stagedconversion

7.M ai nt en an ce i nte rn alISstaff,externalconsultant

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SummaryQuestions

B oo k N ot es

1) WhatisaSystemDevelopmentMethodology?Whatisitused

for?2) Whatarethe7phasesoftheSDLCmethodology?

3) WhatkindofFeasibilityanalysesneedtobeperformedduring

thePlanningphase?Whyisthesystemdevelopmentschedule

important?

4) WhatarethetwostepsintheSystemsAnalysisphase?What

techniquesandtoolsareusedduringtheSystemsAnalysis

phase?

5) Whattoolsdoprogrammers usuallyuseduringthe

Developmentphase?

6) WhatisthedifferencebetweentheVerificationandthe

Validationtestsperformedduringsystemstesting?

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ProblemswithTraditionalSDLC

SDLCistimeconsuming

SDLCisnotflexible(sequentialprocess)

SDLCgetsusersinputs ONLYduringSystems

analysis.

DesignisfrozenatendofSystemDesign

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Question1

WhichofthefollowingistrueaboutSDLC?

a) Itmighttakeyearstodevelopandimplementa

workinginformationsystem

b) Multipleteams

could

work

simultaneously

on

differentphases

c) Itisthebestmethodologyforsituationswherethe

needsandrequirementsarelikelytochangeduring

thedevelopment process

d) Alloftheabove

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Prototyping

ASDMthataddresses:

Timeconsuming

issue

associated

with

SDLC

SDLCsinabilitytotakecareofnewrequirements

ASDMinwhichtheDevelopmentteamuseslimitedsetofusersrequirementstoquicklybuildaworkingmodeloftheproposedsystemaprototype.

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PrototypingActors

Development team, Users

System analyst, programmer

Users

System analyst, programmer

Identify basicrequirements

Develop aprototype

Is Usersatisfied?

Use theprototype

Revise theprototype

Operationalprototype

Develop final system(improved prototype)

YES

NO

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Prototyping

Advantages

Workingmodelreadyquickly

Worksinsituationwhererequirementsare

changing

Worksinsituationswhereuserscannotexplicitly

expresstheirrequirements

Disadvantage

Onlyalimitednumberofusersinvolved.So,

subjecttopotentialimplementationproblem.

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JointApplicationDevelopment(JAD)

ASDMthataddresses:

The

limited

scale

of

users

involvement

problem

of

Prototyping Potentialimplementationproblemduetolimitedusersinvolvement

ASDMthatbringstogethertheDevelopmentteamandasignificantnumberofuserstodefinesystemrequirementsanddevelopaprototype.

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Identify a validsample of users

Set a JAD team(Users, IS professionals, scribe)

Run the 1st JAD session(JAD team + Facilitator)

Develop system prototype(based on agreed requirements)

Run the 2nd JAD session(JAD team + Facilitator)

Improve system prototype

(based on JAD session results)

Objectives

Identify agreed upon systems requirements

Test the system and identify agreed changes

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Question2

WhichofthefollowingistrueaboutaJAD

facilitator?(Chooseallthatapply)

a) Couldbeanoutsideconsultant

b) Isthe

scribe

who

takes

notes

c) IsresponsibleforcoordinatingtheJADsessions

d) Isresponsiblefordevelopingthesystembased

ontheagreeduponrequirements

e) Alloftheabove

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Advantages:

Helpsalleviate

conflicting

requirements

Itsgreaterusersinvolvementleadstogreateruser

acceptanceoffinalsystem

Disadvantages

Couldbeexpensiveandtimeconsuming

mis5670notes8

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