HistoryCategory: computer / software Date: 16 1401, 15:52 Author: a Views: 55
Software maintenance and systems evolution were first studied by Meir M. Lehman in 1969. Over a period of more than twenty years, his research led to the development of Lyman Laws (Lyman 1997). Key findings of his research include that software maintenance is in fact an evolutionary development, and that software maintenance actually helps to make decisions about understanding what happens to the system (software) over time. Lyman showed that the system is still evolving over time. They become more complex in their evolution and growth over time unless certain measures, such as refactoring code, are taken to reduce complexity.
In the late 1970s, a large and well-known study was conducted by Lientz and Swanson in which the large share of maintenance costs in the software life cycle costs of a software was revealed. They categorized maintenance activities into four classes:
Adaptive - System modification to cope with changes in the software environment (such as DBMSs and operating systems)
Improvement - Implementation of new or existing user changes is required that concerns the status of the software user
Correction - Detects and fixes errors that may have been reported by users
Prevention - Improves software maintenance ease or reliability to prevent future problems
This study showed that about 75% of the maintenance activities were spent on the first two types and error correction accounted for about 21% of the maintenance activities. Many subsequent studies show similar results. Studies show that end-user involvement is very important and plays an important role in collecting new data and requirements and analyzing them, and this is the main cause of any problems in software development and maintenance; Therefore, software maintenance is important because it accounts for a large portion of the total software life cycle costs, and the inability to make software changes with adequate speed and reliability means that business opportunities are lost.