Editing Linux on embedded systems (section)

==History== 

{{Main|Linux kernel version history}}
: additional source for this section <ref name="2net">{{cite web |title=Embedded Linux Timeline |url=https://2net.co.uk/embedded-history |website=2net}}</ref>

=== Early Days ===

Prior to becoming the de-facto standard for microprocessor-based devices,<ref>{{cite book |last1=Kingman |first1=Henry |title=The History of Embedded Linux & Best Practices for Getting Started |date=July 2013 |publisher=Linux Foundation |page=2}}</ref> a linux distribution was created for the [[Linux Router Project]], with the intent of transforming PCs to routers.
 
=== Introduction of [[uClinux]] ===
Starting in the late 1990s and the first decade of the 21st century, the introduction of [[uCLinux]] enabled ports to a large variety of [[microprocessors]].<ref>{{cite web |last1=Opdenacker |first1=Michael |title=Introduction to uClinux |url=https://bootlin.com/doc/legacy/uclinux/uclinux_introduction.pdf |website=bootlin.com}}</ref> Linux is also used as an alternative to using a [[Proprietary software|proprietary]] [[operating system]] and its associated [[toolchain]].<ref name="vxworks-migration">{{cite web
 | url = http://www.mvista.com/download/Migrating-VxWorks-apps-to-embedded-Linux-slides-with-notes.pdf
 | archive-url = https://web.archive.org/web/20140210185142/http://www.mvista.com/download/Migrating-VxWorks-apps-to-embedded-Linux-slides-with-notes.pdf
 | title = Migrating VxWorks applications to Linux
 | year = 2008 | access-date = 2013-11-13 | archive-date = 2014-02-10
 | publisher = Monta Vista Software
}}</ref>

=== Introduction of [[busybox]] ===
The introduction of [[busybox]] in 1999, enabled packaging critical tools in an embedded system, with a minimal footprint.

=== The [[ARM architecture family|ARM]]-[[Linux]] Synergy ===

As mentioned in the article [[ARM architecture family]], due to their low costs, low power consumption, and low heat generation, arm processors are prevalent in many embedded devices. The open source nature, the flexibility, and the stability of Linux contributes to its wide-spread adoption to ARM devices.<ref>{{cite web |last1=Vuong |first1=Kent |title=Linux on ARM: The Future of Operating Systems in a Connected World |url=https://www.linkedin.com/pulse/linux-arm-future-operating-systems-connected-world-kent-vuong/ |website=LinkedIn}}</ref>

=== Development Toolchains ===
The development of the [[GNU]] [[cross-compiler]] facilitated the adoption of Linux embedded to many processors.

=== [[Android (operating system)|Android]] ===

In 2008 Android 1.0 was released, based on the linux kernel.  [[Android (operating system)|Android]], a Linux-kernel-based operating system acquired and extended by [[Google]] and introduced in 2008, has become a highly competitive platform for [[smartphone]]s and [[tablet computer|tablet]]s. In time, [[Android (operating system)|Android]] would become the most successful linux embedded distribuition.<ref name="2net"></ref>

=== 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.

=== [[IoT]] ===
The open source nature and security features of Linux, have contributed to its prevalence in [[Edge Computing|devices on the Edge]] and [[IoT]] Systems.<ref>{{cite web |last1=Cintay |first1=Emre |title=The Impact of Linux on Emerging Technologies: IoT, AI, and Beyond |url=https://medium.com/%40Chinacolt/the-impact-of-linux-on-emerging-technologies-iot-ai-and-beyond-4b9ca9a06cf2 |website=Medium |access-date=24 April 2025}}</ref> Correspondingly, the demand for the real time capabilities described in the previous subsection, is driven by the proliferation of IoT devices. 

=== Containerization ===
The emerging technologies of the [[fourth industrial revolution]] have driven further enhancements to the linux kernel, notably the adoption of [[Containerization (computing)|containerization]].<ref>{{cite web |title=Guide to Building Embedded Linux Systems with Containers |url=https://pantacor.com/embedded-linux/guide-to-building-embedded-linux-systems-for-iot-with-containers |website=Pantacor}}</ref>