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17 Chapter 16: Trends in System Development Systems Analysis and Design in a Changing 17 Chapter 16: Trends in System Development Systems Analysis and Design in a Changing World

Reasons for Slow Development u Rework l Using the wrong software l Not meeting Reasons for Slow Development u Rework l Using the wrong software l Not meeting minimum quality standards u Shifting l requirements and project changes Changes to design and construction u Improper l tools and techniques for project Reduces quality, increases development time u Poor Project Management Systems Analysis and Design in a Changing World, 3 rd Edition 2

Cost of Change in Each Project Phase Systems Analysis and Design in a Changing Cost of Change in Each Project Phase Systems Analysis and Design in a Changing World, 3 rd Edition 3

What is RAD? u Collection of development approaches, techniques, tools, and technologies u RAD What is RAD? u Collection of development approaches, techniques, tools, and technologies u RAD proven to shorten development schedules u No universal RAD approach shortens every project schedule u No technique, tools or technology fits perfectly u Key is identifying overall development approach and matching set of techniques, tools, techniques most suitable to approach and specific project Systems Analysis and Design in a Changing World, 3 rd Edition 4

Rapid Application Development u RAD is overused and poorly understood u Software developers claim Rapid Application Development u RAD is overused and poorly understood u Software developers claim they do, but cannot precisely define u Equated with tools and techniques l Prototyping, fourth-generation programming languages, CASE tools l Object-oriented analysis, design, and development u Tool vendors and methodologies claim RAD u Competing and confusing claims Systems Analysis and Design in a Changing World, 3 rd Edition 5

Development Approach as a Function of Project Characteristics Systems Analysis and Design in a Development Approach as a Function of Project Characteristics Systems Analysis and Design in a Changing World, 3 rd Edition 17 7

Prototyping Approach to Development u Discovery prototype l Used in analysis or early design Prototyping Approach to Development u Discovery prototype l Used in analysis or early design l Uncover or refine system requirements l Can be thrown away u Developmental prototype l Not thrown away l Part of iterative development until final system complete Systems Analysis and Design in a Changing World, 3 rd Edition 8

When to Use a Prototyping Approach u When to use: l Requirements cannot be When to Use a Prototyping Approach u When to use: l Requirements cannot be fully specified outside of architectural or detailed design l Technical feasibility unknown or uncertain l Development tools powerful enough to create functional system u When not to use: l System is non-interactive or internally complex l Strict security or performance requirements exist Systems Analysis and Design in a Changing World, 3 rd Edition 9

Prototyping Tool Requirements u Development u Flexibility speed and power u Techniques and capabilities Prototyping Tool Requirements u Development u Flexibility speed and power u Techniques and capabilities l WYSIWYG (what you see is what you get) l Generation of complete programs, program skeletons, or database schemas from diagrams l Rapid customization of software libraries or components l Error-checking and debugging capabilities Systems Analysis and Design in a Changing World, 3 rd Edition 10

Prototyping Tools u Simple l Access l Excel l Graphical u Visual Studio. NET Prototyping Tools u Simple l Access l Excel l Graphical u Visual Studio. NET u Power. Builder u Oracle Forms Systems Analysis and Design in a Changing World, 3 rd Edition 11

Prototyping FPF Principle u Make it Functional u Make it Pretty u Make it Prototyping FPF Principle u Make it Functional u Make it Pretty u Make it Fast Systems Analysis and Design in a Changing World, 3 rd Edition 12

Spiral Approach to Development u Iterative l development approach Each iteration may include combination Spiral Approach to Development u Iterative l development approach Each iteration may include combination of planning, analysis, design, or development steps u More radical departure from traditional development than prototyping development Systems Analysis and Design in a Changing World, 3 rd Edition 13

17 The Spiral Life Cycle Systems Analysis and Design in a Changing World, 3 17 The Spiral Life Cycle Systems Analysis and Design in a Changing World, 3 rd Edition 14

Steps in the Spiral Development Approach u Criteria for feature selection for each prototype Steps in the Spiral Development Approach u Criteria for feature selection for each prototype l User priorities l Uncertain requirements l Function reuse l Implementation risk u Break into categories l “Must have”, “Should have”, “Nice to have” l Complete high priorities earlier to reduce risk Systems Analysis and Design in a Changing World, 3 rd Edition 15

Benefits and Risks of Spiral Development u Benefits l High parallelism l High user Benefits and Risks of Spiral Development u Benefits l High parallelism l High user involvement l Gradual resource commitment l Frequent product delivery u Risks l Management difficulties and design complexity l More potential for rework Systems Analysis and Design in a Changing World, 3 rd Edition 16

17 Cumulative Cost Plotted Against Time Systems Analysis and Design in a Changing World, 17 Cumulative Cost Plotted Against Time Systems Analysis and Design in a Changing World, 3 rd Edition 17

The Unified Process u Comprehensive development approach l Originally developed by Jacobsen, Booch, and The Unified Process u Comprehensive development approach l Originally developed by Jacobsen, Booch, and Rumbaugh in late 1990 s l Dominant approach for developing software with OO models and tools l Adopts iteration from prototyping and spiral development approaches l Exclusive reliance on OO models, tools, and techniques Systems Analysis and Design in a Changing World, 3 rd Edition 23

UP Phases and Objectives (Figure 16 -2) Systems Analysis and Design in a Changing UP Phases and Objectives (Figure 16 -2) Systems Analysis and Design in a Changing World, 3 rd Edition 24

The Unified Process Life Cycle (Figure 16 -1) Systems Analysis and Design in a The Unified Process Life Cycle (Figure 16 -1) Systems Analysis and Design in a Changing World, 3 rd Edition 25

When to Use the Unified Process u Benefits u Major and risks mirror spiral When to Use the Unified Process u Benefits u Major and risks mirror spiral development obstacles to adopt UP include: l Complex project management (compared to sequential development) required l Need to adopt OO models, tools, techniques throughout project u UP’s formal steps, well-defined roles, attention to model building and validation makes UP preferred approach for large-scale development Systems Analysis and Design in a Changing World, 3 rd Edition 29

Rapid Development Techniques u Collection of guidelines used to help an analyst complete system Rapid Development Techniques u Collection of guidelines used to help an analyst complete system development activities or tasks l Risk management l Joint application design (JAD) l Tool-based development l Software reuse l Object frameworks Systems Analysis and Design in a Changing World, 3 rd Edition 30

Components and the Development Life Cycle u Purchased system components can form part or Components and the Development Life Cycle u Purchased system components can form part or all of u Components provide one model for designing and deploying systems u Component issues l Internally developed components l Object-oriented techniques l Designing components for reuse Systems Analysis and Design in a Changing World, 3 rd Edition 43

17 Activities Added to SDLC Phases when Components are Purchased Systems Analysis and Design 17 Activities Added to SDLC Phases when Components are Purchased Systems Analysis and Design in a Changing World, 3 rd Edition 44