Software re-engineering is a process of examining and altering a software system to restructure it and improve maintainability. It involves sub-processes like reverse engineering, redocumentation, and data re-engineering. Software re-engineering is applicable when some subsystems require frequent maintenance and can be a cost-effective way to evolve legacy software systems. The key advantages are reduced risk compared to new development and lower costs than replacing the system entirely.

1. A SEMINAR ON THE TOPIC
UNDER THE GUIDANCE OF
PROF R.B.HANJI
BY:
` ABHILASH .A.M
ABHILASH SHET
AKSHAY KUMAR
AMRUT DESHPANDE
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2.  It is a process of software development
which is done to improve the maintainability
of a software system.
 Technical Definition: Software Re-
engineering is the examination and alteration
of a system to reconstitute it in a new form.
 This process encompasses a combination of
sub-processes such as reverse engineering,
restructuring, redocumentation, forward
engineering, and retargeting.
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3.  It is sometimes a cost-effective option for
software system evolution.
 Applicable when some (but not all) subsystems
of a larger system require frequent
maintenance.
 It involves putting in the effort to make it easier
to maintain.
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4.  Legacy systems are the old software systems
which are essential for business process
support.
 Software re-engineering is concerned with
re-implementing legacy systems to make
them more maintainable. It may be the only
viable way to ensure that legacy systems can
continue in service.
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5. Re-engineering a software system has
two key advantages:
 Reduced risk: As the software is already
existing, the risk is less as compared to
developing a new software.
 Reduced cost: The cost of re-engineering is
significantly less than the costs of developing
a new software.
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6. 1) Source code translation
2) Reverse Engineering
3) Program structure improvement
4) Program modularisation
5) Data re-engineering
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7.  It is a process of translating a source code
from one programming language to another.
 The translated language may be an updated
version of the original language or a
completely different language.
 Necessity of Source-level translation:
1.Hardware platform update
2.Staff skill shortages
3.Organisational policy changes
4.Lack of software support
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8. System to be System to be Re-engineered
re-engineered re-engineered
System
Identify
source Design Automatically Manually
code translator translate translate
differences instructions code code
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9.  It is the process of analysing software with
the objective of recovering its design and
specification.
 The program itself is unchanged by the
reverse engineering process.
 The software source code is usually available
as the input.
 Reverse Engineering is not the same as
Re-engineering
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10. Program
structure
diagrams
Automated
analysis
System
System to be Document Data structure
Information
re-engineered generation diagrams
Store
Manual
annotation
Traceability
matrices
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11.  It is the process of improving the structure of
the program to optimise memory use and the
lack of understanding of s/w engineering.
 Typically, programs develop this complex
logic structure as they are modified during
maintenance.
 New conditions and associated actions are
added without changing the existing control
structure.
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12. Program to be
Restructured
restructured program
Analyser and Program
graph builder generator
Graph representation
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13. Problems with automatic program
restructuring include:
1) Loss of comments
2) Loss of documentation
3) Heavy computational demands
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14.  It is the process of reorganizing a program so
that related program parts are collected
together and considered as a single module.
 Different types of modules may be created:
1.Data abstractions
2.Hardware modules
3.Functional modules
4.Process support modules
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15. Recovering Data Abstraction:
 Data abstractions collect together data and
associated processing and are resilient to
change.
 Steps in converting global data areas to
abstract data types:
1.Analyse common data areas to identify logical data
abstractions.
2.Create an abstract data type for each of these
abstractions.
3.Use a program browsing system/cross reference
generator to find all references to the data.
 Practically difficult and time-consuming,but
straightforward.
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16.  It is the process of analysing and reorganising
data structures in a system to make it more
understandable.
 Why do we have to modify data and
programs in a legacy system ?
1.Data degradation
2.Inherent limits that are built into the
programs
3.Architectural evolution
 Expensive and time-consuming process.
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17. Program to be re-engineered Data analysis
Entity name Data
modification reformatting
Literal Default value Data
Data replacement conversion conversion
analysis
Data definition Validation rule
reordering modification
Stage 1 Stage 2 Stage 3
Change summary tables Modified data
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18.  Software Re-engineering
 its needs
 advantages.
 Steps involved in Software re-engineering.
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19. Overall Software re-engineering process can be
shown as :
Program Modularised
Original program Original data
documentation program
Reverse
engineering
Source code Program Data
translation modularisation re-engineering
Program
structure
improvement
Structured Re-engineered data
program
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20.  Software re-engineering is a cost-effective
option for software system evolution.
 Software re-engineering consists of a
combination of many sub-processes.
 Data re-engineering is different from
software re-engineering.
 Data re-engineering is an expensive and time
consuming process.
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21. Ian Sommerville- Software Engineering, sixth
edition, Pearson Education
 Bruce R. Maxim- Software Reengineering
ppt, CIS 376, UM-Dearborn
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