Comparison of real-time operating systems

This is a list of real-time operating systems (RTOSs). This is an operating system in which the time taken to process an input stimulus is less than the time lapsed until the next input stimulus of the same type.

class="wikitable sortable mw-datatable" ! Name !! License !! Source model	Target uses !! Status !! Platforms
Apache Mynewt	{{free\|Apache 2.0}}	\| open source	embedded	active	ARM Cortex-M, MIPS32, Microchip PIC32, RISC-V
BeRTOS	{{free\|Modified GNU GPL}}	open source	embedded	archived	ARM, Cortex-M3, ARM ARM7TDMI, Atmel AVR, PowerPC (emu), x86 (emu), x86-64 (emu)
ChibiOS/RT	{{free\|Dual, GNU GPL or proprietary}}	open source	embedded, small footprint \|active	x86, ARM7, ARM9, Cortex-M0-M3-M4, PowerPC e200z, STM8, STM32, AVR, MSP430, ColdFire, H8S
ChorusOS	{{dunno}}	{{dunno}}	{{dunno}}	defunct	SPARC, x86, PowerPC
Contiki	{{free\|BSD}}	open source	embedded, WSN	active	MSP430, AVR, ARM
Data General RDOS	{{proprietary}}	{{dunno}}	general purpose	defunct	Data General Nova, Data General Eclipse
Deos	{{proprietary}}	closed	safety critical	rowspan="2" \| active	x86, PowerPC, ARM, MIPS
DioneOS	{{proprietary}}	available for licensee	embedded	MSP430, MSP430x
DNIX	{{proprietary}}	closed	general purpose	defunct	68000
GEC DOS	{{proprietary}}	closed	process control	defunct	GEC 4000 series
DSOS	{{proprietary}}	closed	{{dunno}}	defunct	TI-980A minicomputer
DSP/BIOS	{{proprietary}}	closed, available with license	general purpose	maintenance only	Mostly Texas Instruments C2800, C5500, C6000 and OMAP DSP cores. Replaced by TI-RTOS, but available for download.
eCos	{{free\|Modified GNU GPL}}	open source \| rowspan="2" \|embedded	inactive	ARM-XScale-Cortex-M, CalmRISC, 680x0-ColdFire, fr30, FR-V, H8, IA-32, MIPS, MN10300, OpenRISC, PowerPC, SPARC, SuperH, V8xx
eCosPro	{{free\|Modified GNU GPL or [http://www.ecoscentric.com/ecospro-license.shtml eCosPro license]}}	open source with non-free portions	active	ARM7-9, Cortex-A5-A9-M3-M4-M7, 680x0-ColdFire, H8-H8S, IA-32, MIPS32, MIPS64, microMIPS, NIOS II, OpenRISC, PowerPC, SPARC, SH4/4A, TILE-Gx, XScale
embOS	{{proprietary}}	closed, available to customers, free object code for non-commercial use	embedded, industrial, IoT, safety critical	rowspan="2" \| active	ARM7/9/11, ARM Cortex-A/R/M, AVR, AVR32, C16x, CR16C, ColdFire, H8, HCS12, M16C, M32C, MSP430, NIOS2, PIC18/24/32, R32C, R8C, RISC-V, RL78, RH850, RX100/200/600/700, RZ, SH2A, STM8, ST7, V850, 78K0, 8051
ERIKA Enterprise	{{free\|GPL and GPL linking exception}}	open source	embedded	ARM7, ARM Cortex-M, ARM Cortex-A (on Jailhouse hypervisor), Hitachi H8, Altera Nios2, Microchip dsPIC (including dsPIC30, dsPIC33, and PIC24), Microchip PIC32, ST Microelectronics ST10, Infineon C167, Infineon Tricore, Freescale PPC e200 (MPC 56xx) (including PPC e200 z0, z6, z7), Freescale S12XS, EnSilica eSi-RISC, AVR, Lattice Mico32, MSP430, Renesas RX200, x86-64 (on Jailhouse hypervisor)
EROS	{{free\|Modified GNU GPL}}	open source	experimental research use	dormant	IA-32
FlexOS	{{proprietary}}	closed	general purpose, industrial, POS	defunct	186, 286, 386, V60, V70, 68000
FreeRTOS	{{free\|MIT}} \| rowspan="2" \|open source \| embedded \| rowspan="5" \|active	ARM, AVR, AVR32, ColdFire, ESP32, HCS12, IA-32, Cortex-M3-M4-M7, Infineon XMC4000, MicroBlaze, MSP430, PIC, PIC32, Renesas H8/S, RISC-V, RX100-200-600-700, 8052, STM32, TriCore, EFM32
Fuchsia	{{partial\|Varies}}	embedded	AArch64, x86-64
Keil RTX	{{free\|Apache 2.0}}	open source	embedded	Arm Cortex-M
FunkOS	{{free\|Modified Sleepycat License}}	open source	embedded	AVR, MSP430, Cortex-M3
HeartOS	{{proprietary}}	closed	safety critical	x86, PowerPC, ARM
Huawei LiteOS	{{free\|BSD}}	open source	embedded	defunct	ARM (M0/3/4/7, A7/17/53, ARM9/11), x86, RISC-V
HarmonyOS	{{proprietary}}	closed	embedded	active	AArch64, x86-64, RISC-V, LingxiISA
IBM 4680 OS	{{proprietary}}	rowspan="4" \| closed	rowspan="2" \| general purpose, industrial, POS	defunct	286
IBM 4690 OS	{{proprietary}}	rowspan="7" \| active	286, 386
INTEGRITY	{{proprietary}}	rowspan="2" \| embedded	ARM, XScale, Blackfin, ColdFire, MIPS, PowerPC, x86
INtime	{{proprietary}}	x86
ITRON	{{free\|T-License}}	varies	embedded	ARM, MIPS, x86, Renesas RX100-200-600-700-others
Kaspersky OS	{{proprietary}}	rowspan="2" \| open source	safety critical, virtualization	x86, x86_64, ARMV5, ARMV7, ARMV8, MIPS32
KolibriOS	{{free\|GNU GPL}}	embeddable	x86
LynxOS	{{proprietary}}	source available	embedded	Motorola 68010, x86/IA-32, ARM, Freescale PowerPC, PowerPC 970, LEON
Mbed OS	{{free\|Apache 2.0}}	open source	embedded	abandoned {{Cite web \|title=Important Update on Mbed \|url=https://os.mbed.com/blog/entry/Important-Update-on-Mbed/ \|access-date=2024-07-16 \|language=en}}	Arm Cortex-M
MenuetOS	{{free\|GNU GPL}}	open source	active	{{dunno}}	IA-32
MERT	{{proprietary}}(Bell Labs)	closed	OS for long-distance telephone switching systems	inactive	PDP-11
MicroC/OS-III	{{free\|Apache 2.0}}	open source	embedded	active	ARM7-9-11/Cortex-M1-3-4-A8/9, AVR, HC11/12/S12, ColdFire, Blackfin, MicroBlaze, NIOS, 8051, x86, Win32, H8S, M16C, M32C, MIPS, 68000, PIC24/dsPIC33/PIC32, MSP430, PowerPC, SH, StarCore, Renesas RX100-200-600-700, RL; STM32, ...
MontaVista Linux	{{free\|GNU GPL}}	open source	embedded	{{dunno}}
MP/M	{{proprietary}}	closed (meanwhile: open source)	general purpose, industrial	defunct	8080, Z80, 8086
MQX	{{proprietary}}	complimentary source available	embedded	active	Freescale Power, ColdFire, Kinetis Cortex ARM, List of Freescale products
Multiuser DOS	{{proprietary}}	closed	general-purpose, industrial	defunct	386
Nano-RK	{{free\|Dual, GPL or commercial}}	open source	embedded, WSN	defunct	AVR, MSP430
Neutrino	{{proprietary}}	some source provided	microkernel, embedded, industrial	rowspan="6" \| active	ARM, ARM64, MIPS, PPC, SH, x86, x86-64, XScale
Nucleus RTOS	{{proprietary}}	source provided \|embedded	ARM (Cortex-M3-M4-R4-R4F-A8-A9, ARM7-9-11), PowerPC, MIPS32-16e, microMIPS, ColdFire, SuperH
NUT	{{proprietary}} \| rowspan="2" \|open source	embedded, industrial	ARM-M0, ARM-M0+, ARM Cortex-M3, ARM9, ARM Cortex-M7, Cortex-M3
Nut/OS	{{free\|BSD}}	embedded, industrial	AVR, AVR32, ARM7, ARM9, Cortex-M3
NuttX	{{free\|Apache 2.0}}	open source	embedded, small footprint	Linux user mode, ARM7-9, Cortex-A5-A8-A9-M0-M3-M4-M7, 8052, Espressif ESP32, Lattice LM32, Renesas MC16C/26/SH-1, RISC-V, Zilog Z16F, Zilog eZ80 Acclaim!, Zilog Z8Encore!, Z80, MIPS PIC32MX, PIC32MZ
OpenComRTOS	{{proprietary}}	source provided	embedded	Freescale PowerPC, Texas Instruments C66xxx DSP, ARM, XMOS, MicroBlaze, LEON, NXP CoolFlux DSP, Melexis MLX16, Win32, Linux
OS2000	{{proprietary}}	{{dunno}}	embedded	active	MIPS (Baget variant), KOMDIV-32, KOMDIV-64, Intel BSPs (x86)
OS4000	{{proprietary}}	closed	process control	maintenance only	GEC 4000 series
OSE	{{proprietary}}	available to customers	general purpose \| rowspan="3" \|active	ARM, PowerPC, x86, TI OMAP, ...
OS-9	{{proprietary}}	available to customers	rowspan="2" \| embedded	ARM-strongARM, MIPS, PowerPC, SuperH, x86/Pentium, XSCALE, Motorola 6809, 680x0, SPARC
OSEK	{{free\|Dual, GPL or commercial}}	specification	engine control units
Phoenix-RTOS	{{free\|BSD}}	open source	embedded \| rowspan="2" \|active	ARMv7 Cortex-M, ARMv7 Cortex-A, IA-32, RISC V
PikeOS	{{proprietary}}	available to customers	certifiable safety & security, embedded virtualisation	PPC, x86, ARM, MIPS, SPARC-LEON, RISC-V
Protothreads	{{free\|BSD}}	open source	general purpose \|active	Architecture independent
pSOS	{{proprietary}}	{{dunno}}	{{dunno}}	discontinued	680x0
PX5 RTOS	{{proprietary}}	royalty-free licensing	embedded	rowspan="5" \| active	Embedded MCU and MPU architectures. ARM's Cortex-M, Cortex-R, Cortex-A, RISC-V. AMP and SMP configurations.
QNX	{{proprietary}}	{{dunno}}	microkernel, embedded, industrial	active
QP	{{free\|Dual, GPL or commercial}}	dual	MCU, DSC, DSP SoC	ARM7/9, ARM Cortex-M3-M0, MSP430, TMS320C28x, AVR, AVRXmega, ColdFire, 68HC08, M16C/R8C, H8, 8051, 80251, PIC18, PIC24/dsPIC33, Nios II, PSoC1
REAL/32	{{proprietary}}	closed	general-purpose, industrial	386
Real-time Linux (PREEMPT RT)	{{free\|GNU GPLv2}}	open source	general purpose	x86, x86_64, RISC-V, ARM64 and LoongArch (ARM and POWER in the -rt branch)[https://wiki.linuxfoundation.org/realtime/preempt_rt_versions PREEMPT_RT patch versions]
REX OS	{{proprietary}}	closed, available with license	rowspan="4" \| embedded	inactive	ARM
RIOT	{{free\|GNU LGPL}}	open source	active	ARM7, ARM Cortex M, MSP430, AVR, RISC-V, Xtensa
RMX	{{proprietary}}	closed	defunct	Intel 8080, 8086, 80386, higher
RODOS	{{free\|BSD}}	source provided	active	ARMv7 (M3, A8, A9), AVR32, PowerPC 405, SPARC64 Platforms: SmartFusion2, RaspberryPi, STM32 On an OS: Linux, Windows, macOS, FreeRTOS, RTEMS
RSX-11	{{proprietary}}	{{dunno}}	{{dunno}}	historic	PDP-11
RT-11	{{proprietary}}	{{dunno}}	general purpose	defunct	PDP-11
RTAI	{{free\|GNU GPL}}	rowspan="3" \| open source	general purpose	rowspan="2" \| active	x86 (with and without FPU and TSC), x86-64, PowerPC, ARM (StrongARM; ARM7: clps711x-family, Cirrus Logic EP7xxx, CS89712, PXA25x), m68k (supporting both MMU and NOMMU cpus)
RTEMS	{{free\|BSD}}	embedded	AArch64, ARM, Blackfin, ColdFire, TI C3x/C4x, H8/300, x86, x86_64, 68k, Microblaze, Milkymist SoC, MIPS, Nios II, PowerPC, SuperH, SPARC, ERC32, LEON, Mongoose-V
RTLinux	{{free\|GNU GPL}}	general purpose	inactive	same as Linux
RT-Thread	{{free\|Apache 2.0}}	open source	embedded \| rowspan="3" \|active	ARM, ARM Cortex-M0-M3-R4-M4-M7, IA-32, AVR32, Blackfin, nios, PPC, M16C, MIPS (loongson-1b-1c, PIC32，xburst), MicroBlaze, V850, unicore32,
RTXC Quadros	{{proprietary}}	source available	embedded	ARM - Atmel/Freescale/NXP/ST/TI, Blackfin, 680x0-ColdFire, PowerPC, StarCore, TI-Luminary Stellaris, TI OMAP, XScale
RTX, RTX64	{{proprietary}}	closed	MS Windows extension	x86, x86-64
RX116	{{dunno}}	{{dunno}}	embedded, industrial	rowspan="3" \| defunct	NEC V20, NEC V30, NEC V40, NEC V50
RX616	{{dunno}}	{{dunno}}	safety critical, embedded, industrial	NEC V60, NEC V70
RX-UX832	{{dunno}}	{{dunno}}	embedded, industrial, general-purpose	NEC V60, NEC V70
SafeRTOS	{{proprietary}}	source code & Design Assurance Pack available	embedded, safety critical	active	Same as FreeRTOS
SHaRK	{{free\|GNU GPL}} \|open source	{{dunno}}	inactive	{{dunno}}
Simulink Real-Time	{{proprietary}}	closed	real-time testing-embedded	active	x86
SINTRAN III	{{proprietary}}	{{dunno}}	{{dunno}}	{{dunno}}	Norsk Data computers
Symbian OS	{{free\|Eclipse}}	open source	embedded	defunct	ARM
T-Kernel	{{free\|T-License}}	source available	embedded RTOS	active	ARM, MIPS, SH, more
THEOS	{{proprietary}}	{{dunno}}	{{dunno}}	{{dunno}}	{{dunno}}
ThreadX	{{free\|MIT}}	open source	embedded, IoT, safety critical	rowspan="2" \| active	ARC, ARM/Thumb, AVR32, BlackFin, 680x0-ColdFire, H8-300H, Luminary Micro Stellaris, M-CORE, MicroBlaze, PIC24-dsPIC, PIC32, MIPS, V8xx, Nios II, PowerPC, Renesas RX100, RX200, RX600, RX700, Synergy, SH, SHARC, StarCore, STM32, StrongARM, TMS320C54x, TMS320C6x, x86/x386, XScale, Xtensa/Diamond, ZSP
TI-RTOS Kernel (SYS/BIOS)	{{free\|BSD}}	open source \|embedded	Mostly Texas Instruments: MSP430-432, C2000-5000-6000, TI's ARM families (Cortex M3-4F-R4-A8-A15), SimpleLink Wireless CC2xxx-CC3xxx
TizenRT	{{free\|Apache 2.0}}	open source	embedded	active
Transaction Processing Facility	{{proprietary}}	mixed	general purpose	active	IBM Z series
TRON project	{{Free}}	mixed	mixed	active	any: is a specification, not an implementation
UNIX-RTR	{{dunno}}	{{dunno}}	{{dunno}}	defunct	PDP-11
UNOS	{{dunno}}	{{dunno}}	{{dunno}}	historic	680x0
μITRON	{{free\|T-License}}	open source	embedded	active	ARM, MIPS, x86, Renesas RX100-200-600-700-others
μ-velOSity	{{proprietary}}	{{dunno}}	microkernel	rowspan="2" \| active	{{dunno}}
velOSity	{{proprietary}}	{{dunno}}	{{dunno}}	Power ISA, ARM/XScale, MIPS, x86/Pentium, ColdFire, Blackfin, OMAP, DaVinci
VAXELN	{{proprietary}}	closed source	{{dunno}}	historic	VAX
VRTX	{{proprietary}}	{{dunno}}	{{dunno}}	superseded by Nucleus RTOS	ARM, MIPS, PowerPC, RISC
VxWorks	{{proprietary}}	{{dunno}}	rowspan="3" \| embedded	rowspan="4" \| active	ARM, IA-32, Intel 64, MIPS, PowerPC, SH-4, StrongARM, xScale
Windows CE	{{proprietary}}	Microsoft Shared Source	x86, MIPS, ARM, SuperH
Windows 10 IoT	{{proprietary}}	{{dunno}}	Intel Atom, Celeron, Pentium; Qualcomm Snapdragon, Broadcom, NXP i.MX
Xenomai	{{free\|GNU GPLv2}}	rowspan="2" \| open source	general	x86, x86-64, PowerPC, ARM, Analog Devices Blackfin BF52x, BF53x, BF54x and BF56x
XINU	{{free}}	embedded	active	x86, MIPS, ARM, AVR
XMK	{{free\|BSD}}	open source	embedded	inactive
Zephyr	{{free\|Apache 2.0}}	open source	embedded	active	ARM (Cortex-M0, ARM Cortex-M3
M3, ARM Cortex-M4
M4, ARM Cortex-M23
M23, ARM Cortex-M33
M33, ARM Cortex-R
R4, ARM Cortex-R
R5, ARM Cortex-A
A53), x86, ARC, RISC-V, Nios II, Xtensa, SPARC

References

External links

[https://github.com/user-attachments/files/17348393/Beningo-RtosPerformance-2024-Report.pdf 2024 RTOS Performance Report] (FreeRTOS / ThreadX / PX5 / Zephyr) - Beningo Embedded Group
[https://web.archive.org/web/20170904172524/http://www.embedded.com/design/operating-systems/4425751/2/Comparing-microcontroller-real-time-operating-systems 2013 RTOS Comparison] (Nucleus / ThreadX / ucOS / Unison) - Embedded Magazine

Category:Embedded operating systems

Real-time operating systems