Software Re-Engineering

1. Software
Engineering-L11
Sameera
Gunathilaka
Lead Software
Engineer
ERP Technical
Consultant
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Institute of Technology, University of Moratuwa
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2. IT1204 – Software Engineering
Institute of Technology, University of Moratuwa
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3. IT1204 – Software Engineering
Institute of Technology, University of Moratuwa
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What
to
do?

4. IT1204 – Software Engineering
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5. IT1204 – Software Engineering
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6. Why Software Re-engineering?
• ‘Trying to figure out the structure and behavior of existing
software by building general-level static and dynamic models’
• 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
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Institute of Technology, University of Moratuwa
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7. Advantages of Re-engineering
• Reduce Risk
• Risk is less than developing new software
• Reduced Cost
• Cost of developing a new software is significantly high than Re-engineering
• Productivity increases
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8. Re-Engineering cost factors
•The quality of the software to be re-engineered.
•The tool support availability for engineering.
•Extent of the data conversion which is required.
•The availability of expert staff for Re-engineering.
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9. When RE is needed
• When the programming language or platform is no longer
supported. (IFS converted Centura code to C#.net code)
• There is a drastic change in technology. ( IFS windows technology
was changed to web based technologies)
• Business processes in the company are changing.( Banking
System)
• If the software is initially poor. ( LinkedIn/ Autolanka.com)
• A technology appears which is perfect for your goals.
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10. Forward
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11. Forward Engineering
“Forward engineering is the traditional process of moving
from high-level abstractions and logical, implementation-
independent designs to the physical implementation of a
system."
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14. Understanding and
transformation
Existing
software system
Re-engineered
system
Design and
implementation
System
specification
New
system
Software re-engineering
Forward engineering
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15. Software Re-engineering
• Reorganising and modifying existing software systems to make them
more maintainable
• Examination and alteration of a system to reconstitute it in a new
form
• The principles of Re-Engineering when applied to the software
development process is called software re-engineering
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16. Some Software re-engineering activities
• Source code translation into another programming language
• Database reorganization or its transfer
• Software architecture optimization
• New functionality addition and integration with third-party APIs.
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Institute of Technology, University of Moratuwa
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17. Software
Re-Engineering
Cycle
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18. Inventory Analysis
• Every software organisation should have an inventory of all the
applications.
• Inventory can be nothing more than a spreadsheet model containing
information that provides a detailed description of every active
application.
• By sorting this information according to business criticality, longevity,
current maintainability and other local important criteria, candidates for
re-engineering appear.
• Resource can then be allocated to candidate application for re-
engineering work.
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19. Document reconstructing
• Documentation of a system either explains how it operate or how to
use it.
• Documentation must be updated.
• It may not be necessary to fully document an application.
• The system is business critical and must be fully re-documented.
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Institute of Technology, University of Moratuwa
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20. Reverse Engineering
• Reverse engineering is a process of design recovery.
• Reverse engineering tools extracts data, architectural and procedural
design information from an existing program.
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Institute of Technology, University of Moratuwa
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21. Code Reconstructing
• The source code is analysed using a reconstructing tool.
• Violations of structured programming construct are noted and code is
then reconstruct.
• The resultant restructured code is reviewed and tested to ensure that
no anomalies have been introduced.
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22. Data Restructuring
• Data restructuring begins with the reverse engineering activity.
• Current data architecture is dissected, and necessary data models are
defined.
• Data objects and attributes are identified, and existing data structure
are reviewed for quality.
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23. Forward Engineering
• Forward Engineering also called as renovation or reclamation not only
for recovers design information from existing software but uses this
information to alter or reconstitute the existing system in an effort to
improve its overall quality.
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24. Thank you
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