SIM - Mc leod ch07

© 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e RManagement Information Systems, 10/e Raymond McLeod and George Schell aymond McLeod and George Schell

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Management Management Information Systems, Information Systems,

10/e10/eRaymond McLeod and George Raymond McLeod and George

Schell Schell

© 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e RManagement Information Systems, 10/e Raymond McLeod and George Schell aymond McLeod and George Schell

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Chapter 7Chapter 7

Systems DevelopmentSystems Development

© 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod and George Schell

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Learning ObjectivesLearning Objectives

►Recognize the systems approach as the Recognize the systems approach as the basic framework for solving problems of basic framework for solving problems of all kinds.all kinds.

►Know how to apply the systems Know how to apply the systems approach to solving systems problems.approach to solving systems problems.

►Understand that the systems Understand that the systems development life cycle (SDLC) is a development life cycle (SDLC) is a methodology – a recommended way to methodology – a recommended way to develop systems.develop systems.


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Learning Objectives (Cont’d)Learning Objectives (Cont’d)

► Be familiar with the main SDLC approaches Be familiar with the main SDLC approaches – the traditional waterfall cycle, prototyping, – the traditional waterfall cycle, prototyping, rapid application development, phased rapid application development, phased development, and business process development, and business process redesign.redesign.

► Know the basics of modeling processes with Know the basics of modeling processes with data flow diagrams and use cases.data flow diagrams and use cases.

► Understand how systems development Understand how systems development projects are managed in a top-down fashion.projects are managed in a top-down fashion.

► Be familiar with the basic processes of Be familiar with the basic processes of estimating project cost.estimating project cost.


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The Systems ApproachThe Systems Approach

► John Dewey identified three series of John Dewey identified three series of judgments involved in adequately resolving judgments involved in adequately resolving a controversya controversy

1.1.Recognize the controversyRecognize the controversy2.2.Weigh alternative claimsWeigh alternative claims3.3.Form a judgmentForm a judgment

►During the late 1960s/early 1970s, interest During the late 1960s/early 1970s, interest in systematic problem solving strengthenedin systematic problem solving strengthened

► Systems approachSystems approach—a series of problem-—a series of problem-solving steps that ensure the problem is first solving steps that ensure the problem is first understood, alternative solutions are understood, alternative solutions are considered, and the selected solution works.considered, and the selected solution works.


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Series of StepsSeries of Steps

► Preparation effortPreparation effort prepares the problem prepares the problem solver by providing a systems orientation.solver by providing a systems orientation. Business areas, level of management, resource Business areas, level of management, resource

flowsflows

►Definition effort Definition effort consists of identifying the consists of identifying the problem to be solvedproblem to be solved & then understanding it.& then understanding it.

► Solution effortSolution effort involves identifying involves identifying alternative solutions, evaluating them, alternative solutions, evaluating them, selecting the one that appears best, selecting the one that appears best, implementing that solution, & following up to implementing that solution, & following up to ensure that the problem is solved.ensure that the problem is solved.


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Figure 7.1 Phases & Steps of Figure 7.1 Phases & Steps of Systems ApproachSystems Approach


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Figure 7.2 Each Business Area is Figure 7.2 Each Business Area is a Systema System


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Definition Effort TerminologyDefinition Effort Terminology

►Problem triggerProblem trigger is a signal that things is a signal that things are going better or worse than planned.are going better or worse than planned.

►SymptomSymptom is a condition that is produced is a condition that is produced by the problem & is usually more obivious by the problem & is usually more obivious than the root cause of the problem.than the root cause of the problem.

►ProblemProblem is a condition or event that is is a condition or event that is harmful or potentially or beneficial or harmful or potentially or beneficial or potentially beneficial to the firm.potentially beneficial to the firm.


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Figure 7.3 Analyze System Parts Figure 7.3 Analyze System Parts in Sequencein Sequence


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Select the Best SolutionSelect the Best Solution

►AnalysisAnalysis – a systematic evaluation of – a systematic evaluation of options.options.

►JudgmentJudgment – the mental process of a – the mental process of a single manager.single manager.

►BargainingBargaining – negotiations between – negotiations between several managers.several managers.


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Systems Development Systems Development LifecycleLifecycle

►MethodologyMethodology is a recommended way of is a recommended way of doing something.doing something.

► Systems development lifecycle (SDLC)Systems development lifecycle (SDLC) is an application of the systems approach to is an application of the systems approach to the development of an information system.the development of an information system.

► Traditional SDLC stages are:Traditional SDLC stages are: PlanningPlanning AnalysisAnalysis DesignDesign ImplementationImplementation Use.Use.


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Figure 7.4 Circular Pattern of Figure 7.4 Circular Pattern of the System Life Cyclethe System Life Cycle


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PrototypingPrototyping

►PrototypePrototype is a version of a potential is a version of a potential system that provides the developers & system that provides the developers & future users with an idea of how the future users with an idea of how the system in its completed form will system in its completed form will function.function.

►PrototypingPrototyping is the process of is the process of producing a prototype.producing a prototype.

►Best suited for small systems – Best suited for small systems – reflecting the prototyping influence.reflecting the prototyping influence.


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Evolutionary PrototypeEvolutionary Prototype

► Evolutionary prototypeEvolutionary prototype is continually is continually refined until it contains all of the refined until it contains all of the functionality that users require of the new functionality that users require of the new system. The steps involved are:system. The steps involved are: Identify user needs.Identify user needs. Develop prototype.Develop prototype.

► Integrated application developerIntegrated application developer►Prototyping toolkitPrototyping toolkit

Determine if the prototype is acceptable.Determine if the prototype is acceptable. Use the prototype.Use the prototype.


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Figure 7.5 Development of Figure 7.5 Development of Evolutionary PrototypeEvolutionary Prototype


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Requirements PrototypeRequirements Prototype

►Requirements prototypeRequirements prototype is developed as is developed as a way to define the functional requirements a way to define the functional requirements of the new system when users are unable to of the new system when users are unable to articulate exactly what they want. Begin articulate exactly what they want. Begin with the Evolutionary Prototype steps, then with the Evolutionary Prototype steps, then the next steps are:the next steps are: Code the new system;Code the new system; Test the new system;Test the new system; Determine if the new system is acceptable;Determine if the new system is acceptable; Put the new system into production.Put the new system into production.


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Figure 7.6 Development of Figure 7.6 Development of Requirements Prototype Requirements Prototype


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Attraction of PrototypingAttraction of Prototyping

► Communications between the developer & Communications between the developer & user are improved.user are improved.

► The developer can do a better job of The developer can do a better job of determining the users’ needs.determining the users’ needs.

► The user plays a more active role in system The user plays a more active role in system development.development.

► The developers & the user spend less time & The developers & the user spend less time & effort developing the system.effort developing the system.

► Implementation is much easier because the Implementation is much easier because the user knows what to expect.user knows what to expect.


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Potential Pitfalls of Potential Pitfalls of PrototypingPrototyping

► The haste to deliver the prototype may The haste to deliver the prototype may produce shortcuts in problem definition, produce shortcuts in problem definition, alternative evaluation, & documentation. The alternative evaluation, & documentation. The shortcut produces a “quick & dirty” effort.shortcut produces a “quick & dirty” effort.

► The user may get overly excited about the The user may get overly excited about the prototype, leading to unrealistic expectations prototype, leading to unrealistic expectations regarding the production system.regarding the production system.

► Evolutionary prototypes may not be very Evolutionary prototypes may not be very efficient.efficient.

► The computer-human interface provided by The computer-human interface provided by certain prototyping tools may not reflect good certain prototyping tools may not reflect good design techniques.design techniques.


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Rapid Application Rapid Application DevelopmentDevelopment

► Rapid Application Development (RAD)Rapid Application Development (RAD), is a , is a term coined by James Martin. It refers to a term coined by James Martin. It refers to a development life cycle intended to produce systems development life cycle intended to produce systems quickly without sacrificing quality.quickly without sacrificing quality.

► Information engineering Information engineering is the name that Martin is the name that Martin gives to his overall approach to system gives to his overall approach to system development, which treats it as a firm-wide activity.development, which treats it as a firm-wide activity.

► EnterpriseEnterprise is used to describe the entire firm. is used to describe the entire firm.► Essential to RAD is management, people, Essential to RAD is management, people,

methodologies, & tools.methodologies, & tools.► Best suited for large systems.Best suited for large systems.


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Figure 7.7 Rapid Application Figure 7.7 Rapid Application DevelopmentDevelopment


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Phased DevelopmentPhased Development

► Phased development is an approach for Phased development is an approach for developing information systems that developing information systems that consists of six stages: consists of six stages: Preliminary investigationPreliminary investigation AnalysisAnalysis DesignDesign Preliminary constructionPreliminary construction System testSystem test Installation.Installation.

► Best suited for systems of all sizes.Best suited for systems of all sizes.


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Figure 7.8 Stages of Phases Figure 7.8 Stages of Phases DevelopmentDevelopment


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Module PhasesModule Phases

►System is subdivided into major System is subdivided into major modules such as:modules such as: Report writer;Report writer; Database;Database; Web interface.Web interface.

►Number of modules varies with the Number of modules varies with the system from 1 to a dozen or so.system from 1 to a dozen or so.

►Stages are performed separately for Stages are performed separately for each module.each module.


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Figure 7.9 Module Phase of Figure 7.9 Module Phase of Systems DevelopmentSystems Development


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Business Process RedesignBusiness Process Redesign

►ReengineeringReengineering or or Business process redesignBusiness process redesign ((BPRBPR) is the process of reworking the systems.) is the process of reworking the systems. Systems include both those that process the firm’s Systems include both those that process the firm’s

data & those that perform basic functions such as data & those that perform basic functions such as drilling for oil.drilling for oil.

►BPRBPR affects the firm’s IT operations in two ways: affects the firm’s IT operations in two ways: Aids in the redesign of old information systems (Aids in the redesign of old information systems (legacylegacy

systems);systems); Applies to the redesign of information systems to Applies to the redesign of information systems to

support major operations.support major operations.► Usually initiated at strategic management level.Usually initiated at strategic management level.


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Figure 7.10 Top-Down Initiation Figure 7.10 Top-Down Initiation of BPR Projects of BPR Projects


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Strategic Initiation of BPRStrategic Initiation of BPR

►Reverse engineeringReverse engineering is the process of is the process of analyzing an existing system to:analyzing an existing system to: identify its elements & their interrelationships;identify its elements & their interrelationships; Create documentation at a higher level of Create documentation at a higher level of

abstraction than currently exists.abstraction than currently exists.► FunctionalityFunctionality is the job that it performs. is the job that it performs.►ReengineeringReengineering is the complete redesign of is the complete redesign of

a system with the objective of changing its a system with the objective of changing its functionality.functionality.

► Forward engineeringForward engineering is given to the is given to the process of following the SDLC in the normal process of following the SDLC in the normal manner while engaging in BPR.manner while engaging in BPR.


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BPR ComponentsBPR Components

►BPR components can be applied BPR components can be applied separately or in combination.separately or in combination.

►Functional qualityFunctional quality is a measure of is a measure of what the system does.what the system does.

►Technical qualityTechnical quality is a measure of is a measure of how well it does it.how well it does it.


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Figure 7.11 BPR Component Figure 7.11 BPR Component SelectionSelection


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Methodologies in PerspectiveMethodologies in Perspective

►Traditional SDLCTraditional SDLC is an application of the is an application of the systems approach to the problem of system systems approach to the problem of system development; contains all elements.development; contains all elements.

►PrototypingPrototyping is an abbrev. form focusing on is an abbrev. form focusing on the definition & satisfaction of user needs.the definition & satisfaction of user needs.

►RADRAD is an alternative approach to the design is an alternative approach to the design & implementation phases of SDLC.& implementation phases of SDLC.

►Phased developmentPhased development uses traditional SDLC uses traditional SDLC & applies it in a modular fashion. & applies it in a modular fashion.


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System Development ToolsSystem Development Tools

► Process modelingProcess modeling was first done with was first done with flowchartsflowcharts.. ISO standardsISO standards Use of 20+ symbolsUse of 20+ symbols

►Data flow diagrams (DFD)Data flow diagrams (DFD) is a graphic is a graphic representation of a system that uses four representation of a system that uses four symbol shapes to illustrate how data flows symbol shapes to illustrate how data flows through interconnected processes..through interconnected processes..

►DFDs are excellent for modeling processes DFDs are excellent for modeling processes at a summary level.at a summary level.


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Data Flow Diagram SymbolsData Flow Diagram Symbols

► TerminatorTerminator describes an environmental element, describes an environmental element, such as a person, organization, or another system.such as a person, organization, or another system. Environmental elementsEnvironmental elements exist outside the boundary of exist outside the boundary of

the system.the system.► ProcessProcess is something than transforms input into is something than transforms input into

output.output.► Data flowData flow consists of a group of logically related consists of a group of logically related

data elements that travel from one point or process data elements that travel from one point or process to another; can to another; can divergediverge and and convergeconverge..

► Data storageData storage is a repository of data. is a repository of data.► Connector Connector contains the number of the process contains the number of the process

that provides the data flow.that provides the data flow.


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Figure 7.12 DFD of a Sales Figure 7.12 DFD of a Sales Commission SystemCommission System


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Leveled Data Flow DiagramsLeveled Data Flow Diagrams

► Leveled DFDsLeveled DFDs is used to describe the hierarchy of is used to describe the hierarchy of diagrams, ranging from context to lowest-level diagrams, ranging from context to lowest-level nn diagram. diagram.

► Figure 0 diagramFigure 0 diagram identifies the major processes of a identifies the major processes of a system.system. Use additional DFDs to achieve documentation at both a more Use additional DFDs to achieve documentation at both a more

summarized & a more detailed level.summarized & a more detailed level.► Context diagramContext diagram is a diagram that documents the is a diagram that documents the

system at a more summarized level.system at a more summarized level. Positions the system in a environmental context.Positions the system in a environmental context.

► Figure Figure nn diagram diagram is a diagram that provides more is a diagram that provides more detail.detail. nn represents the # of processes on the next higher level. represents the # of processes on the next higher level. Documents a single process of a DFD in greater detail.Documents a single process of a DFD in greater detail.


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Figure 7.13 Context Diagram of Figure 7.13 Context Diagram of a Sales Commission Systema Sales Commission System


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Figure 7.14 Figure 4 Diagram of Figure 7.14 Figure 4 Diagram of a Sales Commission Systema Sales Commission System


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Use CasesUse Cases

►Use caseUse case is a narrative description in an is a narrative description in an outline form of the dialog that occurs outline form of the dialog that occurs between a primary & secondary system.between a primary & secondary system.

► Continuous narrative formatContinuous narrative format with each with each action numbered sequentially.action numbered sequentially.

► Ping-pong formatPing-pong format consists of two consists of two narratives & the numbering indicates how narratives & the numbering indicates how the tasks alternate between the primary & the tasks alternate between the primary & secondary systems.secondary systems.

► Alternative events are actions that are not Alternative events are actions that are not normally expected to occur; alphabetic normally expected to occur; alphabetic letters are appended to step numbers.letters are appended to step numbers.


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Figure 7.15 A Use CaseFigure 7.15 A Use Case


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Figure 7.16 Use Case Figure 7.16 Use Case GuidelinesGuidelines


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Project ManagementProject Management

►Steering committeeSteering committee is a committee is a committee with the purpose of providing ongoing with the purpose of providing ongoing guidance, direction, & control of all guidance, direction, & control of all systems projects.systems projects.

►MIS steering committeeMIS steering committee purpose is purpose is directing the use of the firm’s directing the use of the firm’s computing resources.computing resources. It establishes policies.It establishes policies. It provides fiscal control.It provides fiscal control. It resolves conflict.It resolves conflict.


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Figure 7.17 Managers of a Figure 7.17 Managers of a System Life Cycle Arranged in a System Life Cycle Arranged in a

HierarchyHierarchy


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Project LeadershipProject Leadership

►Project teamProject team includes all of the includes all of the persons who participate in the persons who participate in the development of an information development of an information system.system.

►Team leaderTeam leader ( (project leaderproject leader) ) provides direction throughout the life provides direction throughout the life of the project.of the project.


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Project Management Project Management MechanismMechanism

► Basis for project management is the project Basis for project management is the project plan.plan.

►Gantt chartGantt chart is a horizontal bar chart that is a horizontal bar chart that includes a bar for each task to be performed; includes a bar for each task to be performed; bars arranged in time sequence.bars arranged in time sequence.

►Network diagramNetwork diagram ( (CPM diagram, PERT CPM diagram, PERT chartchart) is a drawing that identifies activities & ) is a drawing that identifies activities & links them with arrows to show the sequence links them with arrows to show the sequence in which they are to be performed.in which they are to be performed.

► Narrative reports are in the form of weekly Narrative reports are in the form of weekly written reports by project leader, written reports by project leader, communicates project information to MIS communicates project information to MIS steering committee.steering committee.


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Figure 7.18 A Gantt ChartFigure 7.18 A Gantt Chart


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Figure 7.19 A Network Figure 7.19 A Network DiagramDiagram


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Project Cost-EstimatingProject Cost-Estimating

► Cost-estimating inputsCost-estimating inputs Work breakdown structure (WBS)Work breakdown structure (WBS) Resource requirements, resource ratesResource requirements, resource rates Activity duration estimatesActivity duration estimates Historical informationHistorical information

► Cost-estimating tools & techniquesCost-estimating tools & techniques Bottom-up estimatingBottom-up estimating Computerized estimatingComputerized estimating Mathematical modelsMathematical models

► Cost-estimating outputsCost-estimating outputs Supporting detailsSupporting details Cost-management planCost-management plan


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Table 7.1 Components of Cost-Table 7.1 Components of Cost-Estimating ProcessEstimating Process


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Table 7.2 Example of Project Table 7.2 Example of Project CostCost

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SIM - Mc leod ch07