Editing Linux on embedded systems (section)

=== Real-time Support ===
[[File:Linux embedded Real Time Evolution.png|thumb|Linux embedded Real Time Evolution]]

Not every embedded Linux distribution is required to or meets [[Real-time computing|real-time]] requirements.<ref>{{Citation|last=Erciyes|first=K.|title=Real-Time Operating Systems|date=2019|url=http://link.springer.com/10.1007/978-3-030-22570-4_4|work=Distributed Real-Time Systems|series=Computer Communications and Networks|pages=65–88|place=Cham|publisher=Springer International Publishing|language=en|doi=10.1007/978-3-030-22570-4_4|isbn=978-3-030-22569-8|s2cid=199583025|access-date=2021-03-08|url-access=subscription}}</ref><ref>{{Cite web|title=What does it mean to say "linux kernel is preemptive"?|url=https://stackoverflow.com/questions/5283501/what-does-it-mean-to-say-linux-kernel-is-preemptive|access-date=2021-03-08|website=Stack Overflow}}</ref> This is particular relevant for [[safety critical]] applications and systems.<ref>{{Cite web|title=Real-Time Operating System - an overview {{!}} ScienceDirect Topics|url=https://www.sciencedirect.com/topics/computer-science/real-time-operating-system|access-date=2021-03-08|website=www.sciencedirect.com}}</ref>

The original Linux kernel was not suitable for real-time tasks due to its non-deterministic behavior<ref>{{cite journal |last1=Reghenzani |first1=Federico |title=The real-time linux kernel: A survey on Preempt_RT |journal=ACM Computing Surveys |date=2019 |volume=52 |page=1-36}}</ref>

Early attempts to provide real time support, such as [[RTAI]] were based on a real-time kernel alongside the standard kernel.

In 2005, the [[PREEMPT_RT]] project was initiated to provide a patch to the linux kernel.<ref>{{cite web |title=Real-Time Linux Wiki |url=https://archive.kernel.org/oldwiki/rt.wiki.kernel.org |website=Archive Kernel.org}}</ref><ref>{{cite web |title=PREEMPT_RT patch versions |url=https://wiki.linuxfoundation.org/realtime/preempt_rt_versions |website=Linux Foundation}}</ref>

In 2024, the [[PREEMPT_RT]] patch was fully merged into the Linux kernel for supported architectures.