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

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Chapter 16: Trends in

System Development

Systems Analysis and Design in a Changing World

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Reasons for Slow Development

Rework

Using the wrong software

Not meeting minimum quality standards

Shifting requirements and project changes

Changes to design and construction

Improper tools and techniques for project

Reduces quality, increases development time

Poor Project Management

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Cost of Change in Each Project Phase

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What is RAD?

Collection of development approaches, techniques, tools, and technologies

RAD proven to shorten development schedules

No universal RAD approach shortens every project schedule

No technique, tools or technology fits perfectly

Key is identifying overall development approach and matching set of techniques, tools, techniques most suitable to approach and specific project

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Rapid Application Development

RAD is overused and poorly understood

Software developers claim they do, but cannot precisely define

Equated with tools and techniques

Prototyping, fourth-generation programming languages, CASE tools

Object-oriented analysis, design, and development

Tool vendors and methodologies claim RAD

Competing and confusing claims

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Development Approach as a Function of Project Characteristics

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Prototyping Approach to Development

Discovery prototype

Used in analysis or early design

Uncover or refine system requirements

Can be thrown away

Developmental prototype

Not thrown away

Part of iterative development until final system complete

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When to Use a Prototyping Approach

When to use:

Requirements cannot be fully specified outside of architectural or detailed design

Technical feasibility unknown or uncertain

Development tools powerful enough to create functional system

When not to use:

System is non-interactive or internally complex

Strict security or performance requirements exist

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Prototyping Tool Requirements

Development speed

Flexibility and power

Techniques and capabilities

WYSIWYG (what you see is what you get)

Generation of complete programs, program skeletons, or database schemas from diagrams

Rapid customization of software libraries or components

Error-checking and debugging capabilities

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Prototyping Tools

Simple

Access

Excel

Graphical

Visual Studio .NET

PowerBuilder

Oracle Forms

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Prototyping FPF Principle

Make it Functional

Make it Pretty

Make it Fast

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Spiral Approach to Development

Iterative development approach

Each iteration may include combination of planning, analysis, design, or development steps

More radical departure from traditional development than prototyping development

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The Spiral Life Cycle

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Steps in the Spiral Development Approach

Criteria for feature selection for each prototype

User priorities

Uncertain requirements

Function reuse

Implementation risk

Break into categories

“Must have”, “Should have”, “Nice to have”

Complete high priorities earlier to reduce risk

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Benefits and Risks of Spiral Development

Benefits

High parallelism

High user involvement

Gradual resource commitment

Frequent product delivery

Risks

Management difficulties and design complexity

More potential for rework

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Cumulative Cost Plotted Against Time

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The Unified Process

Comprehensive development approach

Originally developed by Jacobsen, Booch, and Rumbaugh in late 1990s

Dominant approach for developing software with OO models and tools

Adopts iteration from prototyping and spiral development approaches

Exclusive reliance on OO models, tools, and techniques

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UP Phases and Objectives (Figure 16-2)

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The Unified Process Life Cycle (Figure 16-1)

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When to Use the Unified Process

Benefits and risks mirror spiral development

Major obstacles to adopt UP include:

Complex project management (compared to sequential development) required

Need to adopt OO models, tools, techniques throughout project

UP’s formal steps, well-defined roles, attention to model building and validation makes UP preferred approach for large-scale development

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Rapid Development Techniques

Collection of guidelines used to help an analyst complete system development activities or tasks

Risk management

Joint application design (JAD)

Tool-based development

Software reuse

Object frameworks

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Components and the Development Life Cycle

Purchased components can form part or all of system

Components provide one model for designing and deploying systems

Component issues

Internally developed components

Object-oriented techniques

Designing components for reuse

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Activities Added to SDLC Phases when Components are Purchased