Contents

1
Contents

• Introduction
• Requirements Engineering
• Project Management
• Software Design
• Detailed Design and Coding
• Quality Assurance
• Software Maintenance

2
Software Maintenance Process

• The most expensive part of the software lifecycle!

3
Ian Sommerville 1995  Software Engineering, 5th
edition.
4
Types of Maintenance

• Corrective Focuses on fixing defects
• Adaptive Includes all changes to meet the
  evolving needs of the user and the environment
• Perfective perfecting existing functions
• Preventive Preventing system performance from
  degrading to unacceptable levels

5
Use of Maintenance Time
See Schach 97. See Somm 96. See
Pfleeger 98.
6
Maintenance Metrics

• Control complexity
• Data complexity
• Length of identifier names
• Program comments
• Coupling
• Cohesion
• Degree of user interaction

7
Configuration Management

• New versions of software systems are created as
  they change
• For different machines/OS
• Offering different functionality
• Tailored for particular user requirements
• Configuration management is concerned with
  managing evolving software systems
• System change is a team activity
• CM aims to control the costs and effort involved
  in making changes to a system

8
Version and Release Management

• Invent identification scheme for system versions
• Plan when new system version is to be produced
• Ensure that version management procedures and
  tools are properly applied
• Plan and distribute new system releases

9
Storing Versions

• Naive Separate files for each version
• Version handling by numbering schemes
• Double Maintenance Problem
• Solution One original version plus deltas
• Forward deltas
• Backward deltas
• Forward and backward deltas
• Shared Data Problem
• Simultaneous Update Problem
• Solution Check-in/check-out mechanism
• Still a problem Merging versions

10
Tools for Version and Configuration Control

• General
• History- and log-files
• Hierarchical file systems
• ...
• Version Control
• Modification tracking
• Control of development branches
• Efficient storage and retrieval
• Access control
• Merging versions
• ...
• SCCS, RCS, CVS, ...

• File comparators
• Patch generators
• Configuration control
• Dependency management and control
• System creation
• Integration with version control
• ...
• Make, makefile generators, ...

11
Software Rejuvenation

• Redocumentation static analysis adds more
  information
• Restructuring transform to improve code
  structure
• Reverse engineering recreate design and
  specification information from the code
• Reengineering reverse engineer and then make
  changes to specification and design to complete
  the logical model then generate new system from
  revised specification and design