Editing Real-time operating system (section)

==Characteristics==
A key characteristic of an RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's [[Task (computing)|task]]; the variability is "[[jitter]]".<ref>{{cite web |url=http://www.chibios.org/dokuwiki/doku.php?id=chibios:articles:jitter |title=Response Time and Jitter |access-date=2010-12-04 |archive-date=2011-07-23 |archive-url=https://web.archive.org/web/20110723091051/http://www.chibios.org/dokuwiki/doku.php?id=chibios:articles:jitter |url-status=dead }}</ref> A "hard" real-time operating system (hard RTOS) has less jitter than a "soft" real-time operating system (soft RTOS); a late answer is a wrong answer in a hard RTOS while a late answer is acceptable in a soft RTOS. The chief design goal is not high [[throughput]], but rather a guarantee of a [[Real-time computing#Criteria for real-time computing|soft or hard]] performance category. An RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline [[Deterministic algorithm|deterministically]] it is a hard real-time OS.<ref name="Tanenbaum">{{cite book |last=Tanenbaum |first=Andrew |title=Modern Operating Systems |year=2008 |publisher=Pearson/Prentice Hall |location=Upper Saddle River, NJ |isbn=978-0-13-600663-3 |page=160}}</ref>

An RTOS has an advanced algorithm for [[scheduling (computing)|scheduling]]. Scheduler flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications. Key factors in a real-time OS are minimal [[interrupt latency]] and minimal [[thread switching latency]]; a real-time OS is valued more for how quickly or how predictably it can respond than for the amount of work it can perform in a given period of time.<ref>{{cite web |title=RTOS Concepts |url=http://www.chibios.org/dokuwiki/doku.php?id=chibios:articles:rtos_concepts |url-status=dead |access-date=2010-12-04 |archive-date=2011-07-23 |archive-url=https://web.archive.org/web/20110723091110/http://www.chibios.org/dokuwiki/doku.php?id=chibios:articles:rtos_concepts }}</ref>