engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...

, maintainability is the ease with which a product can be maintained to: * correct defects or their cause, *

Repair The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installa ...

or replace faulty or worn-out components without having to replace still working parts, * prevent unexpected working conditions, * maximize a product's useful life, * maximize efficiency, reliability, and safety, * meet new

requirements In product development and process optimization, a requirement is a singular documented physical or functional need that a particular design, product or process aims to satisfy. It is commonly used in a formal sense in engineering design, includi ...

, * make future maintenance easier, or * cope with a changing environment. In some cases, maintainability involves a system of

continuous improvement A continual improvement process, also often called a continuous improvement process (abbreviated as CIP or CI), is an ongoing effort to improve products, services, or processes. These efforts can seek "incremental" improvement over time or "breakth ...

- learning from the past to improve the ability to maintain systems, or improve the reliability of systems based on maintenance experience. In

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

and several other engineering fields, the term maintainability has the following meanings: * A characteristic of design and installation, expressed as the probability that an item will be retained in or restored to a specified condition within a given period of

time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...

, when the

maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doctrine ...

is performed by prescribed procedures and resources. * The ease with which maintenance of a

functional unit In computer engineering, an execution unit (E-unit or EU) is a part of the central processing unit (CPU) that performs the operations and calculations as instructed by the computer program. It may have its own internal control sequence unit (not ...

can be performed by prescribed requirements.

Software engineering

software engineering Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' ...

, these activities are known as

software maintenance Software maintenance in software engineering is the modification of a software product after delivery to correct faults, to improve performance or other attributes. A common perception of maintenance is that it merely involves fixing defects. H ...

(cf.

ISO/IEC 9126 ISO/IEC 9126 ''Software engineering — Product quality'' was an international standard for the evaluation of software quality. It has been replaced by ISO/IEC 25010:2011. The fundamental objective of the ISO/IEC 9126 standard is to address s ...

). Closely related concepts in the software engineering domain are evolvability, modifiability,

technical debt In software development, technical debt (also known as design debt or code debt) is the implied cost of additional rework caused by choosing an easy (limited) solution now instead of using a better approach that would take longer. Analogous with ...

, and

code smell In computer programming, a code smell is any characteristic in the source code of a program that possibly indicates a deeper problem. Determining what is and is not a code smell is subjective, and varies by language, developer, and development meth ...

s. The maintainability index is calculated with certain formulae from lines-of-code measures, McCabe measures and

Halstead complexity measures Halstead complexity measures are software metrics introduced by Maurice Howard Halstead in 1977 as part of his treatise on establishing an empirical science of software development. Halstead made the observation that metrics of the software should ...

. The measurement and tracking of maintainability are intended to help reduce or reverse a system's tendency toward "code entropy" or degraded integrity, and to indicate when it becomes cheaper and/or less risky to rewrite the code than it is to change it.

References

External links

Calculation, Field testing and history of Maintainability Index (MI) (with references)

* {{Software quality Telecommunications engineering Design for X Maintenance Software quality

Software engineering

See also

References

Further reading

External links