Chapter Note
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Chapter4v2.pdf
Chapter 4. Limitation and Economic Implications to Software Change
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4.1 Economic Implications of Software Change
4.2 Limitations to Software Change
4.3. Potential Solutions to Maintenance Problem
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4.1 Economic Implications of Software Change
A large portion of computing resources is spent towards software maintenance.
Studies have shown that the cost ranges between 60 – 75 % of computing resources.
Based on the study by Lientz and Swanson, the allocation for each maintenance type is as follows:
Perfective (50 %),
Adaptive (25 %),
Corrective (20%)
Preventive (5%)
The actual maintenance costs may differ based on applications and settings.
Based on the study by Lientz and Swanson, the allocation for each maintenance type is as follows:
Perfective (50 %),
Adaptive (25 %),
Corrective (20%)
Preventive (5%)
The actual maintenance costs may differ based on applications and settings.
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4.2 Limitations to Software Change All changes requested/required cannot be
performed due to the following reasons
Resources limitation: Lack of skilled maintainer, suitable tools and environment, insufficient budget
Quality of the existing system: Quality becomes so poor that change is virtually impossible and is no longer viable
4.2 Limitations to Software Change All changes requested/required cannot be
performed due to the following reasons
Resources limitation: Lack of skilled maintainer, suitable tools and environment, insufficient budget
Quality of the existing system: Quality becomes so poor that change is virtually impossible and is no longer viable
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Organizational strategy: enough budget is not allocated based on the object analysis of the problem, rather based on the desire to be a par with other organizations.
Inertia: the resistance to change by users (adapt to changes)
Skilled staff: difficulty of attracting and retaining skilled maintenance personnel
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4.3. Potential Solutions to Maintenance Problem
a) Budget and Effort Reallocation: Allocate less resource to un-maintainable or difficult to maintainable system.
More resource should be allocated to specification and design of more maintainable system
b) Complete Replacement of the software: Develop a new system rather than maintaining a legacy system
4.3. Potential Solutions to Maintenance Problem
a) Budget and Effort Reallocation: Allocate less resource to un-maintainable or difficult to maintainable system.
More resource should be allocated to specification and design of more maintainable system
b) Complete Replacement of the software: Develop a new system rather than maintaining a legacy system
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c) Maintenance of existing software: solutions a) and b) are somewhat unrealistic in many cases.
E.g., Provide more cutting edge technology, use- driven functionalities, tools, methods
=> The tool and techniques are subjects in this course!
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