Editing Embedded system (section)

{{Short description|Computer system with a dedicated function}}
{{Use American English|date=December 2017}}

[[File:DHCOM Computer On Module - AM35x.jpg|thumb|right|An ''embedded system'' on a plug-in card with processor, memory, power supply, and external interfaces]]

An '''embedded system''' is a specialized [[computer system]]&mdash;a combination of a [[computer processor]], [[computer memory]], and [[input/output]] peripheral devices&mdash;that has a dedicated function within a larger mechanical or [[Electronics|electronic]] system.<ref name="Barr-glossary">{{cite web |author=Michael Barr |title=Embedded Systems Glossary |work=Neutrino Technical Library |access-date=2007-04-21 |url=http://www.netrino.com/Embedded-Systems/Glossary |author-link=Michael Barr (software engineer)}}</ref><ref>{{cite book |last=Heath |first=Steve |title=Embedded systems design|publisher=Newnes |year=2003 |edition=2 |series=EDN series for design engineers |page=[https://archive.org/details/embeddedsystemsd0000heat/page/2 2] |url=https://archive.org/details/embeddedsystemsd0000heat |url-access=registration|quote= An embedded system is a [[microprocessor]] based system that is built to control a function or a range of functions. | isbn=978-0-7506-5546-0}}</ref> It is embedded as part of a complete device often including electrical or electronic hardware and mechanical parts. 
Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has [[real-time computing]] constraints.  Embedded systems control many devices in common use.<ref name=":0">{{cite book|last=Michael Barr|author2=Anthony J. Massa|title=Programming embedded systems: with C and GNU development tools|publisher=O'Reilly|year=2006|pages=1–2|chapter=Introduction|chapter-url=https://books.google.com/books?id=nPZaPJrw_L0C&pg=PA1 | isbn=978-0-596-00983-0}}</ref> {{as of|2009|alt=In 2009}}, it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems.<ref>{{cite web | title=Real men program in C | last=Barr |first=Michael | page=2 | date=1 August 2009 | work=Embedded Systems Design | publisher=TechInsights (United Business Media) | url=http://www.embedded.com/electronics-blogs/barr-code/4027479/Real-men-program-in-C | access-date=2009-12-23 }}</ref>{{Update inline|reason=Computing has changed a lot since 2009.|date=March 2022}}

Modern embedded systems are often based on [[microcontroller]]s (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) used may be types ranging from general purpose to those specialized in a certain class of computations, or even custom designed for the application at hand. A common standard class of dedicated processors is the [[digital signal processor]] (DSP).

Since the embedded system is dedicated to specific tasks, [[design engineer]]s can optimize it to reduce the size and cost of the product and increase its reliability and performance. Some embedded systems are mass-produced, benefiting from [[economies of scale]].

Embedded systems range in size from portable personal devices such as [[digital watch]]es and [[MP3 player]]s to bigger machines like [[home appliances]], industrial [[assembly lines]], [[robots]], transport vehicles, [[Traffic light control and coordination|traffic light controllers]], and [[medical imaging]] systems. Often they constitute subsystems of other machines like [[avionics]] in [[aircraft]] and [[astrionics]] in [[spacecraft]]. Large installations like [[factories]], [[pipelines]], and [[electrical grid]]s rely on multiple embedded systems networked together. Generalized through software customization, embedded systems such as [[programmable logic controller]]s frequently comprise their functional units.

Embedded systems range from those low in complexity, with a single microcontroller chip, to very high with multiple units, [[peripheral]]s and networks, which may reside in [[equipment rack]]s or across large geographical areas connected via long-distance communications lines.