Chapter 1 Software Quality Assurance Table Of Contents

Chapter 1 Software Quality Assurance

Table Of Contents Chapter 1 v Quality Assurance Basics v What is Quality? v Quality & Reliability v Total Quality Management

Quality Assurance Basics Connotations(intention) of The Word Quality v People see the word quality used as a stand-alone term, with out any adjectives attached to it. v People do not normally use the term good quality to express their satisfaction with the products or service they use. v On the other hand people certainly use the term bad quality to express their dissatisfaction.

Quality Assurance Basics Connotations of The Word Quality v Therefore, the adjective good is simplicity attached to the word quality in the minds of people. v Therefore the word quality connotes good quality to most people, including professionals.

Quality Assurance Basics Various Connotations of The Word Quality v For a customer or end user of product, quality connotes defect-free functioning, reliability, ease of use, acceptable levels of fault tolerance during use, and safety from injury to people or property. v For a customer or end user of a service, quality connotes reliability of performance, ease of obtaining service, expert service, pleasant service, and protection from consequential damage. v For a producer of good, quality connotes conformance of the product to specifications, which may be defined by a government body, an industry association or standards body, or by the producers own organization.

Quality Assurance Basics Various Connotations of The Word Quality v For a provider of services, quality connotes meeting deadlines and delivery of service that conforms to customer specifications and standards which may have been set by a government body, and industry association or standard body, or by the providers own organization. v For government bodies, quality connotes safety and protection of consumers from fraud. v For an industry association or standards body, quality connotes safeguarding the industry's reputation, protecting the industry from frud and lawsuits, and addressing the concerns of consumers, government bodies, and industry itself.

What is Quality v Quality has multiple connotations attached to it. v It is ability to make the same thing the same way, over and over again v Customer buys today is same as what they bought last week or will buy next week v Product meets customer’s expectations 100% of the time v International Organization for Standardization defines quality as the degree to which a set of inherent characteristics fulfills requirement. v Quality can be used with such adjectives as poor, good, or excellent.

What is Quality v The definition contains three key terms: ü Requirements ü Characteristics ü Degree v Requirements can be stated by a customer in a made-to-order scenario* or by product specifications in a commercial off the shelf product* scenario. v Characteristics refers to capability of the deliverable or, in other word robustness (fitness). v Degree implies that quality is a continuum, beginning with zero and moving towards, perhaps, infinity. This inference, however is ambiguous and leads to wrong perception. What is the level of quality “poor” or “good” or “excellent”? Who authorized to define?

What is Quality v Joseph Moses Juran defines quality as “fitness for use, with fitness and use” being crucial to proper understanding of quality.

Quality & Reliability v Quality and reliability are intertwined and are inseparable. v Reliability of a product is its capability to function at the defined level of performance for the duration of its life. v Two phrases are critical in this definition: ü Defined level of performance • Normal performance • Peak performance ü Duration of its life • First life or initial life • Operating life

Quality & Reliability v Defined level of performance is defined in the specifications for the product or service. v It should be 100% or more of the specification and no less. v For example, a car may be capable of being driven at 100 miles per hour, but how long can a car withstand being driven continuously at that speed? v Normally, performance is defined as at two levels: v Normal performance v Peak performance

Quality & Reliability v Duration of its life a product has two life's: v First life or initial life – before any repairs become necessary, normally is specified as the warranty or guarantee period. v After expiration of this life, regular maintenance may be required to maintain performance at the level specified for the product. v Operating life – Is the period time after the warranty expires, assuming maintenance is performed. After expiration of this life, it may not be economical to maintain the product to operate at the specified level of performance

Quality & Reliability v In other words, quality involves delivering the specified functionality under the specified conditions. v Reliability involves delivering the specified functionality at a specified level of performance over the duration of the product life. v Initial life is specified by manufacturers as the warranty period, the life after the warranty period usually is not specified. v Mean time to repair is the average time it takes to restore the product to its original functionality by caring out the necessary repairs. v In terms of software it has no moving parts it is determined by wear and tear.

Alter Configuration of Hardware & Software 1. New operating systems enter the market every three years. 2. New Web browsers or updates to current browser are released regular. 3. New viruses and spyware unleashed on unsuspecting internet users. 4. Computers often are flooded with host of new tools, ranging from office suits to antivirus software to downloadable utilities. 5. Changes are introduced to tiers (middleware) in multitier architecture software products. 6. Software products may make use of shared libraries that are part of the system software supplied along with the operating system.

Alter Configuration of Hardware & Software v 7. Software products may make use of third party code libraries to perform special functions such as rules processing, database independence, etc. These third party code libraries may be updated or modified. v 8. Installing and uninstalling utilities on a system may result in changes to or removal of the shared libraries used by a software product.

Quality & Reliability v All of these activates change the configuration of the system on which a software product is running, and this is where the question of software reliability comes into play. v A software product is said to be reliable if it can withstand minor patches to the operating system and to the middleware. v Software quality professionals cannot predict what future upgrades will be made to the system software. v Nonetheless, software quality professionals recognize that the term reliability is applicable to the domain of software.

Total Quality Management v Total quality management (TQM) is the most popular concept in manufacturing industry today. v Almost all professionally managed manufacturing companies have implemented TQM and practice it diligently. v The software development industry, knowingly or unknowingly, leapfrogged into TQM through process certification such as ISO and CMMI. v ISO defines TQM as “a management approach for an organization, centered on quality, based on the participation of al its members, and aiming at long-term success through customer satisfaction and benefits to all members of the organization and to society. ”

Total Quality Management v TQM is an organization-wide quality initiative, which means it involves entire organization in the management of quality. v One major aim of TQM is to reduce process variation within the organization. v In Japan TQM includes four steps: ü Kaizn ü Atarmae hinshitsu ü Kansei ü Miryoketuki hinshitsu

Total Quality Management v Kaizn – Focus on continues process improvement, to make every process in the organization visible, repeatable, and measurable. v Atarmae hinshitsu – Belief that products will function as they are designed to function. v Kansei – Study the way a user uses the product, to facilitate improvement of the product. v Miryoketuki hinshitsu – Belief that product have aesthetic value along with usability. For example, a car needs to look attractive in addition to its capability to transport people.

Total Quality Management v TQM advocates quality standards in all aspects of organizational function, as well as the philosophy of ”do it right the first time. ” v It also recommends elimination of waste in all its forms. v As it stands today, TQM is adopted to some degree in organizations that have quality assurance at their heart, with inspection, testing, and standards implemented thoroughly and consistently. v Although the concept of quality was developed in manufacturing organizations, all of the concept discussed above are relevant to software development organization as well.