W According to the IEEE (1991), software engineering is defined as follows:

2 W According to the IEEE (1991), software engineering is defined as follows:

a (1) The application of a systematic, disciplined, quantifiable approach to t is

the development, operation and maintenance of software; that is, the

softw

application of engineering to software. (2) The study of approaches as in (1).

are quality?

The characteristics of software engineering, especially the systematic, disci- plined and quantitative approach at its core, make the software engineering environment a good infrastructure for achieving SQA objectives. The methodologies and tools that are applied by software engineering determine, to a considerable extent, the level of quality to be expected from the software process and the maintenance services. Therefore, it is desirable that when making decisions about software methodologies and tools, SQA considera- tions be added to the efficiency and economy considerations associated with software engineering.

It is commonly accepted that cooperation between software engineers and the SQA team is the appropriate way to achieve efficient and economic development and maintenance activities that, at the same time, assure the quality of the product of these activities.

Summary

(1) Define software, software quality and software quality assurance.

■ Software, from the SQA perspective, is the combination of computer programs (the “code”), procedures, documentation, and data necessary for operating the software system. The combination of all four components is needed to assure the quality of the development process as well as the ensuing long years of maintenance.

■ Software quality, according to Pressman’s definition, is the degree of confor- mance to specific functional requirements, specified software quality standards, and Good Software Engineering Practices (GSEP).

■ Software quality assurance: this book adopts an expanded definition of the widely accepted IEEE definition of software quality assurance. According to the expanded definition, software quality assurance is the systematic, planned set of actions necessary to provide adequate confidence that a software develop- ment or maintenance process conforms to established functional technical requirements as well as the managerial requirements of keeping to schedules and operating within the budget.

(2) Distinguish between software errors, software faults and software failures.

■ Software errors are sections of the code that are partially or totally incorrect as a result of a grammatical, logical or other mistake made by a systems analyst, a

Software faults are software errors that cause the incorrect functioning of the

software during a specific application. ■

Summ

Software faults become software failures only when they are “activated”, that

is, when a user tries to apply the specific software section that is faulty. Thus,

the root of any software failure is a software error.

ar y

(3) Identify the various causes of software errors.

There are nine causes of software errors: faulty requirements definition, client– developer communication failures, deliberate deviations from software require- ments, logical design errors, coding errors, non-compliance with documentation and coding instructions, shortcomings of the testing process, procedure errors, and documentation errors. It should be emphasized that all causes of error are human, the work of systems analysts, programmers, software testers, documentation experts, and even clients and their representatives.

(4) Explain the objectives of software quality assurance activities.

The objectives of SQA activities for software development and maintenance are: (1) Assuring, with acceptable levels of confidence, conformance to functional tech-

nical requirements. (2) Assuring, with acceptable levels of confidence, conformance to managerial requirements of scheduling and budgets. (3) Initiating and managing activities for the improvement and greater efficiency of software development and SQA activities.

(5) Distinguish and explain the differences between software quality assurance and quality control.

Quality control is a set of activities carried out with the main objective of withhold- ing products from shipment if they do not qualify. In contrast, quality assurance is meant to minimize the costs of quality by introducing a variety of activities through- out the development and maintenance process in order to prevent the causes of errors, detect them, and correct them in the early stages of development. As a result, quality assurance substantially reduces the rates of non-qualifying products.

(6) Explain the relationship between software quality assurance and software engineering.

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation and maintenance of software. The charac- teristics of software engineering, especially its systematic, disciplined and quantitative approach, make software engineering a good environment for achiev- ing SQA objectives. It is commonly accepted that cooperation between software engineers and the SQA team is the way to achieve efficient and economic develop- ment and maintenance activities that, at the same time, assure the quality of the products of these activities.