Editing Maintainability

{{Short description|Ease of maintaining a functioning product or service}}
{{No footnotes|date=May 2013}}

'''Maintainability''' is the ease of maintaining or providing [[maintenance]] for a functioning product or service. Depending on the field, it can have slightly different meanings.

== Usage in different fields ==
=== Engineering ===
In [[engineering]], maintainability is the ease with which a product can be maintained to:
* correct defects or their cause,
* [[Repairability|Repair]] 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]],
* make future maintenance easier, or
* cope with a changing environment.

In some cases, maintainability involves a system of [[continuous improvement]] - learning from the past to improve the ability to maintain systems, or improve the reliability of systems based on maintenance experience.

=== Telecommunication ===
In [[telecommunications]] 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]], when the [[repair and maintenance|maintenance]] is performed by prescribed procedures and resources.
* The ease with which maintenance of a [[functional unit]] can be performed by prescribed requirements.

=== Software ===
In [[software engineering]], these activities are known as [[software maintenance]] (cf. [[ISO/IEC 9126]]). Closely related concepts in the software engineering domain are evolvability, modifiability, [[technical debt]], and [[code smell]]s.

The maintainability index is calculated with certain formulae from [[Lines of code|lines-of-code measures]], [[McCabe Measure|McCabe measures]] and [[Halstead complexity measures]].

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.

{{FS1037C MS188}}

==See also==
* [[List of system quality attributes]]
* [[Maintenance (technical)]]
* [[Supportability (disambiguation)]]
* [[Serviceability (disambiguation)]]
* [[Software sizing]]
* [[RAMS]]
* [[Throwaway society]]

==References ==

{{Reflist}}

== Further reading ==
*{{cite book |first=Benjamin S. |last=Blanchard |first2=Dinesh C. |last2=Verma |first3=Elmer L. |last3=Peterson |title=Maintainability: A Key to Effective Serviceability and Maintenance Management |url=https://books.google.com/books?id=7B02w3If-GIC |date=1995 |publisher=Wiley |isbn=978-0-471-59132-0}}
*{{cite book |first=Charles E. |last=Ebeling |title=An Introduction to Reliability and Maintainability Engineering |edition=3rd |url=https://books.google.com/books?id=rh2WDwAAQBAJ |date=2019 |publisher=Waveland Press |isbn=978-1-4786-3933-6}}
*{{cite book |first=Joseph D. |last=Patton |title=Maintainability & Maintenance Management |url=https://books.google.com/books?id=NrbpAAAAMAAJ |year=2005 |publisher=Patton Consultants |isbn=978-1-55617-944-0 |edition=4th}}

==External links==
* [http://www.virtualmachinery.com/sidebar4.htm Calculation, Field testing and history of Maintainability Index (MI) (with references)]
* [http://www.verifysoft.com/en_maintainability.html Measurement of Maintainability Index (MI)]
* {{cite book  |first=John T. |last=Foreman |first2=Jon |last2=Gross |first3=Robert |last3=Rosenstein |first4=David |last4=Fisher |first5=Kimberly |last5=Brune |url=http://www.sei.cmu.edu/reports/97hb001.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.sei.cmu.edu/reports/97hb001.pdf |archive-date=2022-10-09 |url-status=live  |chapter=Maintainability Index Technique for Measuring Program Maintainability |title=C4 Software Technology Reference Guide: A Prototype |page=231 |id=CMU/SEI-97-HB-001 |date=January 1997 |publisher=Software Engineering Institute}}

{{Software quality}}
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[[Category:Telecommunications engineering]]
[[Category:Design for X]]
[[Category:Maintenance]]
[[Category:Software quality]]
[[Category:Broad-concept articles]]