Team 7 Maintenance

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Team 7Maintenance

• Deborah Yoon
• Kagan Erdil
• Emily Finn
• Jay Meattle
• Sunyoung Park
• Kevin Keating

Wednesday, December 3
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The Nature of Maintenance

• Maintenance Evolution
• Corrective Correct faults and errors
• Adaptive Adapt to changes in environment
• - business rule, govt 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

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The Nature of Maintenance (Cont)

• 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

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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
• http//catless.ncl.ac.uk/Risks/21.24.htmlsubj2
  .1

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Maintenance Process Models

• Quick fix model
• Boehms model
• Osbornes model
• Iterative Enhancement model
• Reuse oriented model

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Reverse Engineering

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

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Tasks

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

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Tools/Products

• Selection criterias
• Capability
• Features
• Cost/benefit
• Platform
• Programming language
• Ease of use
• Openness of architecture
• Stability of vendor
• Organizational culture

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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

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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

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Maintenance and Iterative Dev

• Dont change the whole system at once
• Minimize downtime
• Ensure final product adheres to user requirements
• Small iterations, small fixes

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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.

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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)

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Agile Software Development and Maintenance

• Since this method considers setting up tools such
  as comprehensive documentation a secondary
  objective, subsequent stages in the softwares
  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.

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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.

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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

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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.

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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

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Linuss 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

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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

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Summary

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