RTOS

https://www.osrtos.com/

List of open source real-time operating systems.

Name	License	Platforms	Description	Version	Links	Last updated
FreeRTOS	Modified GPL	MSP430 ARM AVR ColdFire PIC x86	FreeRTOS is a popular real-time operating system for embedded devices, being ported to 31 microcontrollers. It is distributed under the GPL with an optional exception.	V9.0.0	Code	2016-05-26
RT-Thread	GPL	x86 MIPS PowerPC	RT-Thread is an open source real-time operating system for embedded devices from China. RT-Thread RTOS is a scalable real-time operating system: a tiny kernel for ARM Cortex-M0, Cortex-M3/4, or a full feature system in ARM Cortex-A8, ARM Cortex-A9 DualCor	v2.1.0	GitHub	2016-04-24
Contiki OS	BSD	MSP430 ARM AVR 8051	Contiki is an open source operating system for the Internet of Things. Contiki connects tiny low-cost, low-power microcontrollers to the Internet.	3.0	GitHub	2015-08-24
mbed OS	Apache License	ARM	mbed OS is an open-source embedded operating system designed specifically for the "things" in the Internet of Things (IoT). It includes all the features you need to develop a connected product based on an ARM Cortex-M microcontroller.	5.1	GitHub	2016-09-17
ChibiOS/RT	Modified GPL	MSP430 AVR	ChibiOS is a complete development environment for embedded applications including RTOS, an HAL, peripheral drivers, support files and a development environment.	16.1.8	Code	2017-04-25
NuttX	BSD	ARM AVR 8051 x86	NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 32-bit microcontroller environments, the primary governing standards in NuttX are Posix and ANSI standards.	7.20	Code	2017-03-09
RIOT	LGPLv2.1	MSP430 AVR	RIOT is a real-time multi-threading operating system that supports a range of devices that are typically found in the Internet of Things (IoT): 8-bit, 16-bit and 32-bit microcontrollers.	2017.01	GitHub	2017-02-01
RTEMS	GPL	ARM x86 MIPS PowerPC m68k	RTEMS is an open source RTOS that supports open standard application programming interfaces such as POSIX. It is used in space flight, medical, networking and many more embedded devices.	4.11	Code	2016-09-23
Apache Mynewt	Apache License	ARM	Apache Mynewt OS is a real-time, modular operating system for connected IoT devices that need to operate for long periods of time under power, memory, and storage constraints. It provides a complete environment for prototyping, developing, and managing em	pre_sterly_refactor	GitHub	2016-09-21
RTAI	GPL	ARM x86 PowerPC x86_64 m68k	RTAI is the RealTime Application Interface for Linux - which lets you write applications with strict timing constraints for your favourite operating system. The RTAI distribution includes RTAI-Lab, a tool chain to convert block diagrams into RTAI executab	RTAI 5.0-test1	Code	2015-12-06
Xenomai	GPL	ARM x86 PowerPC	Xenomai is a real-time development framework cooperating with the Linux kernel, in order to provide a pervasive, interface-agnostic, hard real-time support to user-space applications, seamlessly integrated into the GNU/Linux environment.	v3.0.3	Code	2016-09-10
Atomthreads	BSD	AVR	Atomthreads is a free, lightweight, portable, real-time scheduler for embedded systems.	release1.3	GitHub	2017-04-04
StratifyOS	GPL	ARM	StratifyOS is a powerful embedded RTOS for the ARM Cortex M microcontrollers.	v2.2.0	GitHub	2017-04-10
distortos	Mozilla Public License Version 2.0	ARM	Distortos is an advanced RTOS written in C++11.	v0.4.0	GitHub	2017-03-11
Zephyr	Apache License	ARM x86	Zephyr Project is a small, scalable real-time operating system for use on resource-constrained systems supporting multiple architectures.	v1.5.0		2016-08-27
StateOS	GPL v3	ARM	Free, extremely simple and amazingly tiny real-time operating system (RTOS) designed for deeply embedded applications. Target: ARM Cortex-M family. It was inspired by the concept of a state machine.	v4.8	GitHub	2017-04-02
F9 Microkernel	BSD	ARM	F9 microkernel is a microkernel-based (L4-style) kernel to support running real-time and time-sharing applications (for example, wireless communications) for ARM Cortex-M series microprocessors with efficiency (performance + power consumption) and security (memory protection + isolated execution) in mind.		GitHub	2017-02-01
BRTOS	MIT	MSP430 AVR ColdFire PIC	BRTOS is a lightweight preemptive real time operating system designed for low end microcontrollers.		GitHub	2017-02-07
BeRTOS	Modified GPL	AVR x86 PowerPC x86_64	BeRTOS is a real time open source operating system supplied with drivers and libraries designed for the rapid development of embedded software.		GitHub	2017-01-23
Erika Enterprise	Modified GPL	MSP430 ARM AVR	Erika Enterprise is the first open-source Free RTOS that has been certified OSEK/VDX compliant!.	2.7.0	Code	2016-06-15
scmRTOS	MIT	MSP430 AVR	scmRTOS stands for Single-Chip Microcontroller Real-Time Operating System.	v5.1.0	GitHub	2016-04-19
BitThunder	GNU GPL version 2.0	ARM	A Reliable Real-Time Operating System & Application Framework.	stable-0.9.2	GitHub	2015-09-28
TI-RTOS Kernel	Other		TI-RTOS Kernel (formerly known as SYS/BIOS	v3.00.00		2016-07-09
TNeo	Other	ARM	TNeo is a well-formed and carefully tested preemptive real-time kernel for 16- and 32-bits MCUs. It is compact and fast.	v1.08	GitHub	2017-02-25
LibreRTOS	Apache License	AVR	LibreRTOS is a portable single-stack Real Time Operating System. All tasks share the same stack, allowing a large number or tasks to be created even on architectures with low RAM, such as ATmega328P (2kB).	dev-master	GitHub	2017-01-13
IntrOS	GPL v3	ARM	Free, simple and tiny cooperative operating system (OS) designed for deeply embedded applications.	v2.8	GitHub	2017-04-02
embox	Other	MSP430 ARM MIPS PowerPC	Embox is a configurable operating system kernel designed for resource constrained and embedded systems.	v0.3.17	GitHub	2017-04-01
uKOS	GPL v3	ARM	uKOS is a multi-tasking OS suitable for small embedded µController systems. It is based on a preventive multitasking scheduler.	4.0.0		2017-04-26
seL4	Other	ARM	The world's first operating-system kernel with an end-to-end proof of implementation correctness and security enforcement is available as open source.	5.1.0	GitHub	2017-04-27

 

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cocoOS:  cooperative operating system (OS) 

Protothreads:  cooperative operating system (OS) 

 

RTOSs not under active development ( Not updated for more than 2 years )

Name	License	Platforms	Description	Version	Links	Last updated
Femto OS	GPL	AVR	Femto OS: RTOS for small MCU's like AVR.		Code	2012-12-09
Protothreads	BSD	AVR 8051	Protothreads are extremely lightweight stackless threads designed for severely memory constrained systems.			2005-04-08
eCos	GPL	ARM MIPS PowerPC	eCos is a free open source real-time operating system intended for embedded applications. The highly configurable nature of eCos allows the operating system to be customised to precise application requirements, delivering the best possible run-time perfor			2013-08-25
Freescale MQX	Other	ARM ColdFire	The Freescale MQX Real-Time Operating System (RTOS) provides real-time performance within a small, configurable footprint. The RTOS is tightly integrated with the latest 32-bit MCUs and MPUs from Freescale and is provided with commonly used device drivers	4.2.0		2015-03-07
FunkOS	Other	MSP430 AVR	FunkOS is an RTOS for 8-32 bit MCUs including AVR, MSP430, and Cortex M3. Both C and C++ kernels avaiable. Key features include preemption, periodic events, device drivers, and mutex/semaphores. Includes a variety of graphics and filesystem middleware.			2013-04-23
Fusion Embedded RTOS	Other	ARM PowerPC	The Fusion Embedded RTOS (Real-Time Operating System) from Unicoi Systems is a Real-Time OS designed and optimized for networking and media-centric processors.			2015-03-08
MARK3	BSD	AVR	Mark3 is a sophisticated, modern RTOS and application development platform, targeted towards a growing list of today's most compelling embedded devices.		Code	2015-03-08
Nut/OS	GPL	AVR ColdFire	Nut/OS is an intentionally simple RTOS for the ATmega128, which provides a minimum of services to run Nut/Net, the TCP/IP stack.		Code	2014-11-20
Prex	BSD	ARM x86	Prex is an open source, royalty-free, real-time operating system for embedded systems. It is designed and implemented for resource-constrained systems that require predictable timing behavior. The highly portable code of Prex is written in 100% ANSI C bas	0.9.0	Code	2009-10-01
TNKernel	GPL	MSP430 ColdFire	TNKernel is a compact and very fast real-time kernel for the embedded 32/16/8 bits microprocessors.			2013-06-06
uSmartX	BSD	ARM AVR	uSmartX is a non-preemptive, multitasking, priority based RTOS.	1.34	Code	2006-01-14
DuinOS	Other	AVR	DuinOS is a small multithreading real time operating system (RTOS), based on the FreeRTOS kernel, for Arduino compatible boards.	FreeRTOS_V7.4.0	GitHub	2013-04-02

 

 

 

 

List of open source embedded file systems.

Name	License	Description	Version	Links	Last updated
Yaffs	GNU GPL version 2.0	Yaffs (Yet Another Flash File System) is an open-source file system specifically designed to be fast, robust and suitable for embedded use with NAND and NOR Flash.	aleph1-release		2016-07-08
SPIFFS	MIT	Spiffs is a file system intended for SPI NOR flash devices on embedded targets.	0.3.6	GitHub	2016-08-09
FatFs	GPL	FatFs is a generic FAT/exFAT file system module for small embedded systems. The FatFs module is written in compliance with ANSI C (C89) and completely separated from the disk I/O layer. Therefore it is independent of the platform. It can be incorporated into small microcontrollers with limited resource, such as 8051, PIC, AVR, ARM, Z80, 78K and etc.	R0.12b		2016-10-13
eefs	Other	EEFS is for EEPROM File System Project (EEFS). It is a simple file system for memory devices such as EEPROM, RAM, ROM, etc. Currently it is not intended for block oriented devices such as disks and flash devices.	eefs-2.0	GitHub	2014-04-23
NFFS	Apache License	The Newtron Flash File System (nffs) is an open source file system available by default with the Apache Mynewt OS.	dev-master	GitHub	2017-01-05

 

 

 

List of open source graphics user interface (GUI).

Name	License	Description	Version	Links	Last updated
MiniGUI	GPL	MiniGUI is a free software project. It aims to provide a fast, stable, and cross-operating-system graphics user interface (GUI) support system, which is especially fit for real-time embedded systems based-on Linux/uClinux, eCos, and other traditional RTOSes, such as VxWorks, ThreadX, uC/OS-II, and Nucleus.	V3.0.12		2012-01-16
µGUI	Other	µGUI is a free and open source graphic library for embedded systems. It is platform-independent and can be easily ported to almost any microcontroller system. As long as the display is capable of showing graphics, µGUI is not restricted to a certain display technology. Therefore, display technologies such as LCD, TFT, E-Paper, LED or OLED are supported.	V0.31 beta	GitHub	2016-01-02
IUP	Other	IUP is a portable toolkit for building graphical user interfaces. It offers a configuration API in three basic languages: C, Lua and LED. IUP purpose is to allow a program to be executed in different systems without any modification.	3.23	Code	2017-10-12
CGUI	GPL	CGUI is a library that provides you with a set of C-functions to create GUI applications, i.e. windows and window controls like buttons, check-boxes, menus, input boxes etc.	2.0.5	Code	2015-12-15
LittlevGL	MIT	LittlevGL is a free and open-source graphics library providing everything you need to create a Graphical User Interface (GUI) on embedded systems with easy-to-use graphical elements, beautiful visual effects and low memory footprint.	v5.0.0	GitHub	2017-12-25