Software Reengineering

Software Re-Engineering
By Abdul Wahid

Introduction
Objective
Business Re-engineering process
Software Re-engineering process model
Re-engineering Approach
Big Bang
Incremental
Evolutionary
Risks Involved
Summary

Contents

Re-engineering is the examination, analysis and alteration of an existing software system to reconstitute it in a new form, and the subsequent implementation of the new form
Introduction

Re-engineering encompasses a combination of other processes
reverse engineering
Re-documentation
Re-structuring
translation
forward engineering
Re-engineering

Re-structuring or re-writing part or all of a legacy system without changing its functionality
Applicable where some but not all sub-systems of a larger system require frequent maintenance
Re-engineering involves adding effort to make them easier to maintain. The system may be re-structured and re-documented
System Re-engineering

Reorganising and modifying existing software systems to make them more maintainable
Software Re-engineering

Preparation for functional enhancement
Improve maintainability
Migration
Improve reliability
Objectives

Copyright pressman

Software Re-engineering process model
Copyright pressman

Big Bang
Incremental
Evolutionary
Re-engineering Approach

Big Bang Approach

Incremental Approach

Evolutionary Approach

Re-engineering Risks
Tool
Process
Risk Area
Application
Technology
Strategy
Personnel

Technology risks
Recovered information is not useful or used
Reverse engineering to representations that cannot be shared
Reengineering technology inadequate to accomplish reengineering goals
Tool risks
Dependence on tools that do not perform as advertised
Not using installed tools

Strategy risks
Premature commitment to a reengineering solution for an entire system
Failure to have a long-term vision with interim goals
Lack of global view: code, data, process reengineering
No plan for using reengineering tools
Application risks
Reengineering with no local application experts available
Existing business knowledge embedded in source code is lost
Reengineered system does not perform adequately

Process risks
Extremely high manual reengineering costs
Cost benefits not realized in required time frame
Cannot economically justify the reengineering effort
Reengineering effort drifts
Lack of management commitment to ongoing reengineering solution
Personnel risks
Programmers inhibiting the start of reengineering
Programmers performing less effectively to make an unpopular reengineering project look less effective

Software Re-engineering is reorganising and modifying existing software systems to make them more maintainable.
Its purpose is to improve the current system.
occurs at two different levels of abstraction
Business level
Software level
Re-engineering approaches
Big Bang
Incremental
Evolutionary
Risks
Summary

Roger S. Pressman, “Software Engineering: A Practitioner’s Approach, 5thedition”.
Ian Sommerville, “Software Engineering, 6th edition”, 2000.
lindaRosenberg, “Software Re-Engineering”.
A. Sonhaji,MegahMulya, Mubassiran, Nasruddin, Ari Yanuar, “RekayasaUlang (Reengineering)”
Ira D. Baxter,Michael Mehlich, “Reverse Engineering is Reverse Forward Engineering”, 1997
David Eichman, “Factors in Reuse and Reengineering of Legacy Software”. Repository Based Software Engineering Program Research Institute for Computing and Information Systems University of Houston – Clear Lake, 1997
References