Software Maintainability Metrics
Software maturity index is one of the suggested method used to measure the software maintainability where it consider either that modified, added or removed on the concern modules. The various combination of characteristics measures such as source code readability, quality of documentation and software understandability.
Factors influencing software maintainability measurement
(1) Source code readability-Most maintenance will end up modifying the source code which is a cumbersome task to undertake especially if the source code were written by a different programmer and not well organize. The percentage of source code readability is achieved by looking on the number of comments line from the total code. The ratio of comments is derived from the division of comment lines by total line codes. If the ratio is low maintainability the code is more readable. (2) Quality of Documentation- the gunning fox index is a model that measure the document quality .it calculates how readable the words in a text are. The fox index is determined by complexity of the words as well as its length. The better documentation quality is realize when fox index is a bit lower buts the higher it is quality of documentation is poorer.(3) Software understandability-This involved mixture of both documents as well as source code .The synergy of this contributes in the quality of maintainability. Otherwise the maintainability flawed and problematic to conduct. The proposed a tool for measurement was the symbols that can be incorporated within the documents as well as source code. The method was term as language software entailing the entire symbols to be used without source language and key words. The coupling and interrelationship of source code language and document language define high understandability.
The stated measures depict various software maintenance properties. The three aspects computes totally varied feature in same software .Therefore the parameters is said to be subjective hence a tool is necessary to integrate the parameters. The integrated approach model suggested which incorporates the various measures of software maintainability is the fuzzy model which considers the three extents of source code readability, quality of documentation and software understandability. The fuzzy model is organized into fuzzification, knowledge base, inference engines and defuzzification modules. The transformation of inputs to fuzzy values are through fuzzification module .The processing and inferences is established by inference engine which is as a result of production rules programmed by domain expert that can be fired within the knowledge based and fuzzy inputs. There after the defuzzification module will give decisive domain information from fuzzy domain.