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Phased Life Cycle Model Prepared by R.Nancy Beaulah

Phased life cycle model

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Page 1: Phased life cycle model

Phased Life Cycle Model

Prepared by R.Nancy Beaulah

Page 2: Phased life cycle model

Phased Life Cycle Model

Segments the software life cycles in to series of successive activities.

Each phase requires Well defined input information Well defined processes Well defined products

Resources are needed for each phase

Each phase utilizes explicit methods, tools and techniques

Page 3: Phased life cycle model

Phases

Analysis Design

Implementation

System Testing

Maintenance

Sometimes it is

called as Water

Fall Chart

Page 4: Phased life cycle model

Analysis

Consist of two phases▪ Planning▪ Requirements Definition

Activities of Planning▪ Understanding the Problem▪ Perform a feasibility study▪ Developing a solution▪ Determine acceptance criteria▪ Planning the development process

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Analysis

Products▪ System definition▪ Project plan

System definition▪ Expressed in English or in any natural language▪ May use charts, figures, graphs, tables and

equations▪ Notations used depend upon the problem

Project plan▪ Life cycle model to be used▪ Organizational structure

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Analysis

▪ Preliminary development schedule▪ Preliminary cost schedule▪ Preliminary resource schedule▪ Preliminary staffing schedule▪ Tools and techniques used

Time and cost are basically calculated because it is not possible to estimate exactly without doing basic design.

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Analysis

Preliminary Cost Estimate – Planning Stage

Refined Cost Estimate – Preliminary Design Review

Final Cost Estimate – Critical Design Review

Requirements Definition It includes basic functions of software

components in hardware, software, and people subsystem.

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Analysis

The product of requirements definition The product of requirements definition is

a specification that describes▪ The processing environment▪ The required software functions.▪ Performance constraints on the software.▪ Exception handling▪ Acceptance criteria

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Design

Design phase: In the phased model, software design follows

analysis Design phase identified software components

1. Functions.2. Data streams3. Data stores

It specifies relationship among components. It specifies software structures. Maintains a record of design decision. Blueprint for the implementation phase.

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Design

Design phase consist of1. Architectural design2. Detailed design

Architectural design: It involves identifying the software

components dividing them into software modules and conceptual data structures, specifying interconnection among components.

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Design

Detailed design It is concerned with the details of “how

to”▪ Package the processing modules.▪ Implement the processing, algorithm, data

structures and interconnection among modules.

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Implementation

Implementation phase: It involves translation of design

specification into source code and debugging, documentation and unit testing of source code.

Errors: Implementation phase may include

errors in routines, functions, logical errors,and algorithm, errors in data structure layout.

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System Testing

System testing: It involves 2 kinds of activities▪ 1. Integration testing▪ 2. Acceptance testing

Integration testing: Developing a strategy for integrating the

software components into a function requires careful planning so that modules are available for integration when needed.

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System Testing

Acceptance testing: It involves planning an execution of

various type of test that software system satisfied requirements documents.

After getting the acceptance from the customer software system of released for production work and maintenance phase.

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Maintenance Phase

Maintenance Phase: It Includes▪ the enhancement of capabilities.▪ Adaptation of software to new processing

environment.▪ correction of software bugs.

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Summary

Phases are Linear Development Process is not Linear Development activities never

proceed as in water fall chart Only possible when it is possible to

specify everything at the beginning itself

Suitable for developers who developed similar systems

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Reference

Software Engineering Concepts, Richard Fairley