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Software Maintenance


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A place to discuss software maintenance:
Maintenance is the modification of a software product after delivery to correct faults, improve performance, or other product attributes, or to adapt the product to a new or changing environment.

In various studies, maintenance costs have been observed to consume from 50% to 80% of total life cycle costs, and typically consume 65% to 75% of total life cycle costs.
Types of software maintenance:
  • Corrective Maintenance - diagnosis and correction of errors
  • Adaptive Maintenance - modifies software product to properly interface with a changing environment
  • Perfective Maintenance - enhancements to product to either add new capabilities or modify existing functions
  • Preventive Maintenance - changes made to improve future maintainability (reverse engineering/re-engineering)
    Approximate proportions:
  • Corrective 21%
  • Adaptive 25%
  • Perfective 50%
  • Preventive 4%
    According to Larry English of Information Impact International, "70 percent of all computer printouts were used to re-enter data into other databases." "One company reported that 80 - 90 percent of developers’ time was devoted to ‘maintenance’ and of that ‘maintenance,’ 60 - 70 percent was devoted to maintaining interfaces, copying and transforming data from database to database." "Another company reported expending $100 million per year in patching programs and fixing errors in data, created when passing data from one system to another."

    Source: http://www.zifa.com/zifajz01.htm
    See http://www2.umassd.edu/CoursePages/SoftwareEngineering/LectureMat/maintenance.html
    http://www.cpsc.ucalgary.ca/~lamwa/SENG/621/SoftwareMaintenance.htm
    For pragmatic views, http://www.cs.monash.edu.au/~damian/CSC2050/Topics/13.25.SWEng4/html/text.html#preventative_maintenance
    A decent academic outline: http://www.cstp.umkc.edu/~hines/458/mdef.html
    Why Is Software Maintenance So Expensive
    Category Maintenance
  • ( Topic last updated: 2003.10.27 12:17:08 PM )