Date Added: Jun 2011
Software maintenance has been part and parcel of a software system's lifecycle ever since the first computer software was introduced more than half-century ago. Lientz et al., defines software maintenance as, "Activities which keep systems operational and meet user needs" while Boehm's defines the process of software maintenance as "the process of modifying existing operational software". The software maintenance activities make the software systems change over time. In this context Belady and Lehman, defines software evolution as "The dynamic behavior of programming systems as they are maintained and enhanced over their lifetimes."