All software developer firms attempt to develop good quality software. The attribute is defined as measurable characteristics. Attributes to measure the quality of the software can be – Cyclomatic Complexity of software, Cohesion that exists between different entities of the software, Number of the function of points that exists in software, lines of Code in developed software, etc.
Software quality is measured in terms of quality of design and quality of standards. Quality of design is measured in terms of the performance of the software. The quality of software increases if the software is developed according to the specifications. The quality of software improves as the developed software meets the standards that are used to develop the software.
The quality of design consists of using the methods in the software that are used to meet the desired requirements and specifications. If the developed software meets the well-defined and tested benchmarks or standards then we say that software ensures the quality of standards.
Quality of software also depends on customer satisfaction and customer satisfaction depends on hassle-free software experience and development and delivery of software within budget and within schedule.
Quality of software is ensured by conducting a number of software inspections, by reviewing developed software again and again, and by testing developed software. The activities that ensure the quality of the software may be automated or may be manual or a combination of these. Whatever be the defects in the developed software the feedback must be provided to the software developing firm. Thus, feedback is also one of the measures to develop quality software.
To develop quality software it is required to measure the cost of quality. The cost of quality includes the cost of all the factors that are required to develop quality software. The cost of quality depends on quality planning, the number of technical reviews conducted on developed software, equipment used in the development of the software, and training provided.
The cost of quality is also measured by finding the cost involved in the activities to be performed to have insight of the developed software. These activities include inspecting all the processes of the software and software testing.
The quality of the software also depends on the cost incurred if the software fails. If the developed software does not fail then software failure cost disappears. The cost of software failure is detected when there is an error in the developed software before the delivery of the software. If an error is detected before the delivery of the software then it is removed by doing rework, repair, and conducting analysis to find the reason due to which error occurred.
It is also possible that errors are discovered after the software has been delivered, in this case, a complaint is raised by the customers and developed software is returned to the software development firm. To ensure software quality software development firm also provides online support and a warranty period within which the software service is provided. The cost of finding and removing the software increases with time.
Software quality is assured by the software developers and a team of software engineers that are planning to maintain the quality of the software, maintain records that are used to develop software, conducts software analysis, and prepares reports accordingly.
Software developers assure software quality by using solid technical methods and measures, generating technical viewpoints, and conducting software testing. Guidelines are developed by experts to maintain the quality of the software.
The generalized guidelines on which software is developed includes:
- Evaluating developed software
- Conducting audits and reviews
- Finding out standards that are used to develop software
- Using well-established methods that are used to report errors and track them accordingly
- Providing timely feedback to the software development team.
To achieve the quality of the software it is assured that software is developed according to the organizational policy and standards. It is possible that deviation may occur in meeting the project plan, to maintain the standards on which software is developed.
To find the extent to which deviation has occurred software reviews are taken. Reviews are done to find the errors and defects that exist in the software. Review filters the software development process and improves the functionalities of the software. Reviews also make the software development work more uniform.
To reveal errors in functionality, the logic of the software formal technical review is conducted. Formal technical review is also done to assure that the developed software meets up with desired functionality. Formal technical reviews are also conducted to find out whether the software development has followed the uniform standard or not and to make the project manageable.
To detect and remove errors from the developed software defect amplification model can be removed. It is possible that software reviews may not reveal errors in this case the defect amplification model is used.
Software quality is also quantitatively measured.
Following steps are taken to measure the software quality quantitatively:
- All software errors are collected and categorized.
- Steps are taken to find the cause of the defects.
- Once the defects are found steps are taken to correct them.
Although there exist many errors in the software development all can be traced to the following types of errors:
- IES: Incomplete specification
- MCC: Misinterpretation of Customer Communication
- IDS: Intentional Deviation from Specifications
- VPS: Violation of Programming Standards
- EDR: Error in Data Representation
- ICI: Inconsistent Component Interface
- EDL: Error in Design Logic
- IET: Incomplete Testing
- IID: Inaccurate Documentation
- PLT: Error in Programming Language Translation of Design
- HCI: Inconsistent human/computer interface
- MIS: Miscellaneous
Software quality is an essential element of software development. To assure software quality, quantitative data about the software engineering process is collected and evaluated. Software quality assurance is a systematic process and requires a well-defined plan to be followed.
Following are the attribute of god software:
- Correctness: Developed software is error-free.
- Usability: Users should easily use the developed system.
- Efficiency: Software should use a processor, primary and secondary memory, and hard disk space efficiently.
- Reliability: Software should perform functionalities table and should produce correct results each time.
- Integrity: Developed software should be secure and protect its data.
- Adaptability: Software must have the capability to produce desired results under different conditions.
- Accuracy: The software must produce accurate results.
- Robustness: Developed software must be robust and should deliver correct output when given invalid input.
- Maintainability: Changes can be made in the developed software if required.
- Potability: Developed software is platform-independent.
- Reusability: The developed software must be reusable so that it can be used to develop other software.
- Readability: To make changes in the software it is required to have an understanding of the code. To develop an understanding of the code program must be written in such a way that it is readable.
- Testability: Software must be developed in such a way that it can undergo different testing procedures.
- Understandability: The software developed must be understandable by the user as well as the developers.