1. Team 7 Maintenance Deborah Yoon Kagan Erdil Emily Finn Jay Meattle
Sunyoung Park
Kevin Keating
Wednesday, December 3

2. The Nature of Maintenance
Maintenance + Evolution
Corrective: Correct faults and errors
Adaptive: Adapt to changes in environment
- business rule, gov’t policies. ex) bank and ECU
Perfective: Accommodate new user requirements
- successful product results in more changes
- example: adding online HELP command
Preventive: Increase maintainability
- example: code restructuring, documentation updating

3. The Nature of Maintenance (Con’t)
Maintenance is expensive (money, time)
$ 70 billion for 10 billion lines of code spent annually in US
Comprises half time of the total life cycle of software
: 49% for pharmaceutical, 75% for automobile companies
50% is spent on Perfective maintenance
Maintenance is product + service
Consumers judge the quality of the software maintenance in service aspect

4. Why include it?
80% of the 100 billion lines of code in production in the world is unstructured, patched, badly documented
Lost pet fees cost Toronto $700,000

5. Maintenance Process Models
Quick fix model
Boehm’s model
Osborne’s model
Iterative Enhancement model
Reuse oriented model

6. Reverse Engineering Reverse Engineering Recover lost information
Facilitate migration between platforms
Improve/provide documentation
Prove alternative views
Extract reusable components
Cope complexity

7. Tasks Analysis/isolation tasks Change design Code/unit test
Testing- integration, acceptance and regression
Documentation
Reuse and Reusability
Program Understanding
Management and Organizational Issues

8. Tools/Products Selection criterias Capability Features Cost/benefit
Platform
Programming language
Ease of use
Openness of architecture
Stability of vendor
Organizational culture

9. Iterative Development
Small iterations for each change made
Conduct meetings throughout the iterations
In maintenance, a new iteration for each new feature or fixed bug

10. Types of Iterative Development
Extreme Programming (XP)
Shortest possible iterations
Test-First Testing
Acceptance Tests
Rational Unified Process (RUP)
Document User Requirements
Update user requirements throughout the process
Scrum
Daily meetings
Four phases: Planning, Architecture, Sprints, Closure

11. Maintenance and Iterative Dev
Don’t change the whole system at once
Minimize downtime
Ensure final product adheres to user requirements
Small iterations, small fixes

12. Agile Software Development and Maintenance
Industry and technology move extremely fast
Requirements change at rates that swamp traditional methods
Customers have become increasingly unable to definitively state their needs upfront while expected more from their software
The Agile method is an alternative to documentation driven, heavyweight software development processes.

13. Agile Software Development and Maintenance
Agile Manifesto
Individuals and interactions over valued over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
Goals
Primary goal – deliver working software
Secondary goal – set up other work products for the next game (e.g. maintenance)

14. Agile Software Development and Maintenance
Since this method considers setting up tools such as comprehensive documentation a secondary objective, subsequent stages in the software’s life cycle such as maintenance are harder to implement.
However, the best way to go about the actual maintenance stage is probably the Agile method because of its very nature stemming from its primary focus on delivering working software.

15. Component Based Software Dvelopment
construction of software systems that makes use of reusable components.
develop software systems by selecting appropriate off-the shelf components and then assemble them with a well-defined software architecture.
Components and Glue codes
Components
Glue codes
Real World Applications
Enterprise JavaBean, COM , CORBA, etc.

16. Maintenance in CBSD
Role of Maintainers of CBSD is different from that in other custom-built systems.
Maintenance Activities for CBSD
Glueing and wrapping
Tailoring:
Fault identification and isolation
Updating component configuration
Monitoring and auditing system behavior
Component testing

17. Advantages and Disadvantages of CBSD
Components can be reused
they are written only once, and then assembled with their ability to be reused.
Components do not rely on the surrounding system, and the surroundings of a component have no need to know exactly how it performs.
Increased cost efficiency and productivity
Making use of the components is complex
For the developer or maintainer there will be the requirement to keep, a catalogue of the different components and have a good understanding of the different interfaces and the way they work in order to understand the system.

18. Open source - Blurring the Line
Software is available before version 1.0
Blurs the line between development and maintenance
Akin to incremental development
Are now a nearly infinite number of increments
Users are co-developers

19. Linus’s Law “Given enough eyeballs, all bugs are shallow”
“Debugging is parallelizable”
“The total cost of maintaining a widely used program is typically 40% or more of the cost of developing it. Surprisingly this cost is strongly affected by the number of users. More users find more bugs.”
- Frederick P. Brooks, Mythical Man Month

20. Third Party Maintenance
Because source is open, anyone can maintain a project
Not just developer
Companies such as Red Hat, Mandrake SuSE offer maintenance for Linux

21. Summary Estimated at 50% of software life cycle Number of models exist
Method used to develop the software will affect maintenance
Questions?