managing information technologyis.cba.edu.kw/534/class/handouts/ch10.pdf · system design system...
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E. Wainright Martin Carol V. Brown Daniel W. DeHayesJeffrey A. Hoffer William C. Perkins
MANAGINGMANAGINGINFORMATIONINFORMATIONTECHNOLOGYTECHNOLOGY
FIFTH EDITION
CHAPTER 10
METHODOLOGIES FOR CUSTOM SOFTWARE DEVELOPMENT
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Systems development life cycle (SDLC) – a highly structured approach for development of new customized software applications
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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The SDLC Steps
Figure 10.1 The Systems Development Life Cycle
Key characteristic is extensive formal reviews
required at end of each major step
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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The SDLC Steps
Figure 10.2 Cost Breakdown for $1 MillionSDLC Project
Hallmark of SDLC approach: extensive up-front time spent
determining requirements to avoid expensive changes later
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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The SDLC Steps
SDLC:Most often requires a lot of documentationOutputs from one step inputs to nextOften referred to as the “waterfall” model
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Definition Phase – Requirements Definition
Focuses on logical design: processes, data flows, and data interrelationships – not specific physical implementation
Deliverable – system requirements document:Detailed descriptions of inputs and outputs, processes used to convert input data to outputsFormal diagrams and output layoutsRevised cost/benefit analysis Revised plan for remainder of project
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Construction Phase
System Design
System Building
System Testing
Figure 10.3 Characteristics of High Quality Systems
Documentation is a major mechanism of
communication during development process
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Implementation Phase
Installation
Operations
Maintenance
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Implementation Phase – Installation
Figure 10.4 Implementation Strategies
Parallel Strategy
Parallel Strategy
Parallel Strategy
Parallel Strategy
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Implementation Phase – Maintenance
Figure 10.5 Percent of Development Resources Devoted to Maintenance
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Implementation Phase – Maintenance
Figure 10.6 The Widening Gap BetweenOrganization’s Needs and System’s Performance
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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The SDLC Project Team
Usually temporary
Includes personnel from IS and business units
Has a project managerTraditionally from ISCan be from business unitMay be one from eachResponsible for success of project – delivering quality system on time and within budget
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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The SDLC Project Team
Includes systems analystsHave critical rolesWork closely with business managers and end usersHave problem-solving skills, knowledge of IT capabilities, strong business understanding
Has a business sponsor and a champion
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Managing an SDLC Project
Characteristics critical for success: Manageable project sizeAccurate requirements definitionExecutive sponsorship
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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Managing an SDLC Project
(Adapted from Boehm, 1976)
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SYSTEMS DEVELOPMENT LIFE CYCLE METHODOLOGY
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SDLC Advantages and Disadvantages
Figure 10.8 Advantages and Disadvantagesof Traditional SDLC Approach
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PROTOTYPING METHODOLOGY
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Prototyping approach:Takes advantage of availability of fourth generation procedural languages and relational database management systemsEnables creation of system (or part of system) more quickly, then revise after users have tried itIs a type of evolutionary development process
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PROTOTYPING METHODOLOGY
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Prototyping examples:Input and output screens developed for users to test as part of requirements definition
“First-of-a-series” – a completely operational prototype used as a pilot
“Selected features” – only some essential features included in prototype, more added later
Prototyping used as a complete alternative to traditional SDLC methodology
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PROTOTYPING METHODOLOGY
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Prototyping used as a complete alternative to traditional SDLC methodology:
Good when requirements hard to define
Good when system needed quickly
Impractical for large, complex applications
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The Prototyping Steps
Figure 10.9 The Prototyping Life Cycle
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PROTOTYPING METHODOLOGY
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Representatives from IS and user management necessary
Need team members who can quickly build systems using advanced tools
Requires dedicated business user roles
The Prototyping Project Team
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PROTOTYPING METHODOLOGY
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Advantages:Only basic requirements needed at front end
Used to develop systems that radically change how work is done, so users can evaluate
Allows firms to explore use of new technology
Working system available for testing more quickly
Less strong top-down commitment needed at front end
Costs and benefits can be derived after experience with initial prototype
Initial user acceptance likely higher
Prototyping Advantages and Disadvantages
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PROTOTYPING METHODOLOGY
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Disadvantages:End prototype often lacks security and control features
May not undergo as rigorous testing
Final documentation may be less complete
More difficult to manage user expectations
Prototyping Advantages and Disadvantages
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PROTOTYPING METHODOLOGY
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Prototyping within an SDLC Process
Figure 10.10 SDLC with Prototypingto Define Requirements
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PROTOTYPING METHODOLOGY
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Prototyping within an SDLC Process
Figure 10.11 Prototyping/Piloting ReplacesSDLC Definition Phase
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NEWER APPROACHES
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Rapid Application Development (RAD)
Figure 10.12 Four-Step RAD Cycle
Hybrid methodology –aspects of SDLC and prototyping
Goal is to produce a system in less than a year
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NEWER APPROACHES
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Rapid Application Development (RAD)
Joint application design (JAD) – a technique in which a team of users and IS specialists engage in an intense and structured process in order to minimize the total time required for gathering information from multiple participants
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NEWER APPROACHES
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Rapid Application Development (RAD)
Joint application design (JAD) – a technique in which a team of users and IS specialists engage in an intense and structured process in order to minimize the total time required for gathering information from multiple participants
Computer-aided software engineering (CASE) – any software tool used to automate one or more steps of a software development methodology
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NEWER APPROACHES
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Rapid Application Development (RAD)
Figure 10.13 Types of CASE Tools
(Adapted from Valacich, George, and Hoffer, 2001)
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NEWER APPROACHES
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Rapid Application Development (RAD)
Figure 10.14 RAD Advantages and Disadvantages
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NEWER APPROACHES
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Agile Software Development Discipline
Alternative methodology for smaller projects
Based on four key values:SimplicityCommunicationFeedback Courage
One type: Extreme Programming (XP)Programmers write code in pairsUse simple design and frequent testing
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MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF
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Advantages:Helps keep software development costs downUses technical expertise not available in-houseCan often complete projects more quickly
Off-site outsourcing:Onshore – within same country or regionOffshore – not within same country or region
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MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF
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Offshore alternative good option when:System requirements well-defined and remain stableTime is of essence and 7x24 hour availability of resources a good ideaCost of project important
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MANAGING SOFTWARE PROJECTS USING OUTSOURCED STAFF
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Guidelines for managing offsite outsourcer:Manage expectations, not staffTake explicit actions to integrate the offsite workersCommunicate frequentlyAbandoning informal ways may result in increased rigor