Comparison of real-time operating systems


This is a list of real-time operating systems. An RTOS 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.
NameLicenseSource modelTarget usesStatusPlatformsOfficial website
AbassiclosedembeddedactiveAVR32, ATmega, ColdFire, Cortex-A53, Cortex-A9, Cortex-M0, Cortex-M3, Cortex-M4, MSP430, PIC32, TMS320C2000, 80251, 8051
Amoscommercialclosed680x0, 683xx, x86 via emulation
AdAstra-RTKopen sourceembeddedactiveCortex-M3-M4-M7-H7, STM32
AMX -RTOSclosedembeddedactive680x0, 683xx, ARM, ColdFire, MIPS32, PowerPC, x86
Apache Mynewtopen sourceembeddedactiveARM Cortex-M, MIPS32, Microchip PIC32, RISC-V
Arm OSopen sourceembeddedactiveCortex-M, Cortex-R, Cortex-A
uKOSopen sourceembeddedactiveCortex-M3-M4-M7-H7, 6833x, PIC, CSEM icyflex-1, STM32
ARTOS closedpower-system automationactivex86
ARTCOS embedded, robotsdefunctARM9+
Atomosheropen sourceembeddedactiveAVR, STM8, ARM, MIPS
AVIXclosedembeddedactiveAtmel AT91SAM3, EFM32, NXP LPC1300-1700, ST Micro STM32, Texas Instruments LM3S, Toshiba TMPM330, Microchip PIC32MX-PIC24F-PIC24H-dsPIC30F-dsPIC33F
BeRTOSopen sourceembeddedarchivedARM, Cortex-M3, ARM ARM7TDMI, Atmel AVR, PowerPC, x86, x86-64
BOOS-Mooch Coreopen sourceembeddedactiveARMv5TEJ, DSP
BRKosopen sourceembeddedactiveFreescale Kinetis, Freescale Coldfire V1, Freescale HCS08, ST STM32F4xx, NXP LPC11xx, NXP LPC176x, Renesas RX600, Texas Instruments MSP430, Texas Instruments Stellaris LM3S8968, Texas Instruments Stellaris LM4F120H5QR, Atmel ATMEGA328/128 and Microchip PIC18
CapROSopen sourceembeddedactiveIA-32, ARM9
Cesium RTOSsource available to licenseesembeddedactiveARM7-9-11/Cortex-M1-3-4-7-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
ChibiOS/RTopen sourceembedded, small footprintactivex86, ARM7, ARM9, Cortex-M0-M3-M4, PowerPC e200z, STM8, STM32, AVR, MSP430, ColdFire, H8S,
ChorusOSdefunctSPARC, x86, PowerPC
ChronOSopen sourceresearch, general purposeactivex86, ARM
CoActionOS open sourceembeddeddiscontinuedARM Cortex-M3, LPC17xx
cocoOSopen sourceembeddedactiveAVR, MSP430, STM32
Concurrent CP/M,
became MP/M		closed general purpose, industrialhistoric8080, Z80, 8086Digital Research
Concurrent DOS,
became Multiuser DOS		closedgeneral purpose, industrialdefunct8086, 286, 386, 68000, Digital Research
Contikiopen sourceembedded, WSNactiveMSP430, AVR, ARM
COSclosedprocess controldefunctGEC 4000 series
CooCox CoOSopen sourcegeneral purposeinactiveSTM32, NXP LPC1000, TI LM3S8962, Nuvoton NU1xx, Holtek HT32
Deosclosedsafety criticalactivex86, PowerPC, MIPS
DioneOSavailable for licenseeembeddedactiveMSP430, MSP430x
distortosopen sourceembeddedactiveARMv6-M architecture : STM32F0, STM32L0; ARMv7-M architecture, ARM Cortex-M7): STM32F1, STM32F4, STM32F7, STM32L4
DNIXclosedgeneral purposedefunct68000
dnx RTOSopen sourceembedded activeARM Cortex-M3, STM32
GEC DOSclosedprocess controldefunctGEC 4000 series
DSOSdefunctTI-980A minicomputer
DSP/BIOSclosed, available with licensegeneral purposemaintenance onlyMostly Texas Instruments C2800, C5500, C6000 and OMAP DSP cores. Replaced by TI-RTOS, but available for download.
DSPnano RTOSopen sourceMCU, DSC, DSP SoCactiveR8C, M16C, PIC24, dsPIC33
DuinOSopen sourcegeneral purposeactiveAVR
eChronosopen sourceembeddedactiveARM Cortex-M3 - M7https://ts.data61.csiro.au/projects/TS/echronos/
eCosopen sourceembeddedactiveARM-XScale-Cortex-M, CalmRISC, 680x0-ColdFire, fr30, FR-V, H8, IA-32, MIPS, MN10300, OpenRISC, PowerPC, SPARC, SuperH, V8xx
eCosProopen source with non-free portionsembeddedactiveARM7-9, 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
embOSclosed, available to customers, free object code for non-commercial useembedded, industrial, IoT, safety criticalactiveARM7/9/11, 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
Emboxopen sourceembeddedactiveARM, LEON, MicroBlaze, MIPS, PowerPC, x86
Embkernelopen sourceembeddedactiveARM Cortex M
ERIKA Enterpriseopen sourceembeddedactiveARM7, ARM Cortex-M, ARM Cortex-A, Hitachi H8, Altera Nios2, Microchip dsPIC, Microchip PIC32, ST Microelectronics ST10, Infineon C167, Infineon Tricore, Freescale PPC e200 , Freescale S12XS, EnSilica eSi-RISC, AVR, Lattice Mico32, MSP430, Renesas RX200, x86-64
EUROSclosedembeddedactive8/16/32 bit processors: among others AVR, 8051, XC800, 16FX, XC166, ARM, Cortex-M3, PowerPC, Nios II, MIPS32, PIC32
EROSopen sourceexperimental
research use		dormantIA-32
F9 microkernelopen sourceembeddedmaintenanceARM Cortex-M3/M4
Femto OSopen sourceembeddedactiveAVR
Flexible Safety RTOSclosed, available to customersembedded, safety criticalactiveARM9, ARM Cortex-M, ARM Cortex-R, ARM Cortex-A, ColdFire, QorIQ, Infineon TriCore, Infineon AURIX
FlexOSclosedgeneral purpose, industrial, POSdefunct186, 286, 386, V60, V70, 68000Digital Research, Novell
FreeOSEKopen sourceembeddedactiveCortex-M4, MIPS, MSP430, SPARC LEON3
FreeRTOSopen sourceembeddedactiveARM, AVR, AVR32, ColdFire, ESP32, HCS12, IA-32, Cortex-M3-M4-M7, Infineon XMC4000, MicroBlaze, MSP430, PIC, PIC32, Renesas H8/S, RX100-200-600-700, 8052, STM32, TriCore, EFM32
Frostedopen sourceembedded, POSIX compliant, unix-likeactiveARM Cortex-Mhttps://gitlab.com/insane-adding-machines/frosted
Fuchsiaopen sourceembeddedactiveAArch64, x86-64
FunkOSopen sourceembeddedactiveAVR, MSP430, Cortex-M3
Fusion RTOSsemi-general purposeactiveARM, Blackfin, StarCore, DSP 56800E
FX-RTOSsource code providedembeddedactiveARMv6-M, ARMv7-M, ARMv7-A, x86, AVR32, PIC32, MIPS M4K, TI MSP430,
HeartOSclosedsafety criticalactivex86, PowerPC, ARM
Heliumopen sourceEmbeddedActiveHCS08, AVR
HP-1000/RTE
Hybridthreadsopen sourceFPGAactiveXilinx Virtex-II Pro ML310, Xilinx Virtex-II Pro XUP
hyperCOSfree evaluation embeddedactiveARM7, ARM9, Cortex-R, Cortex-M3, Cortex-M4F
IBM 4680 OSclosedgeneral purpose, industrial, POSdefunct286IBM
IBM 4690 OSclosedgeneral purpose, industrial, POSactive286, 386IBM
INTEGRITYclosedembeddedactiveARM, XScale, Blackfin, ColdFire, MIPS, PowerPC, x86
INtimeclosedembeddedactivex86
IntrOSopen sourceembedded, small footprintactiveARM Cortex-M, STM8, AVR8
ITRON, µITRONvariesembeddedactiveARM, MIPS, x86, Renesas RX100-200-600-700-others,
ISIXopen sourceembeddedactiveCortex-M3
iRTOSopen sourceembeddedactiveAVR, ARM7
KolibriOSopen sourceembeddableactivex86
Kithara RTSclosedgeneral purpose, industrialactiveWindows extension, x86, x86-64, Windows XP-10
Leptonopen sourceembeddableactiveARM9, ARM7, CortexM3 et CortexM4
LithOSembedded, industrialactiveLEON2-3-4, x86,
LxWinclosedMS Windows extensionactivex86
LynxOSsource code availableembeddedactiveMotorola 68010, x86/IA-32, ARM, Freescale PowerPC, PowerPC 970, LEON
MaestroclosedembeddedactiveARMv7-A, ARMv8-A, PowerPC64, IA-32
Mark3open sourceembeddedactive, beta
MaRTE OSopen sourceembeddedactiveIA-32
MAX II, IVMODCOMP II, IV,...
MenuetOSopen sourceactiveIA-32
Menuet 64unknownactiveIA-32, x86-64
MicroC/OS-IIIopen sourceembeddedactiveARM7-9-11/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, …
Milosopen sourceembeddedactiveCortex-M3
miosixopen sourceembeddedactivestm32, efm32 e LPC2000
mipOSopen sourceembeddedactiveCortex-M3, ST7, STM8, x86
Microsoft Invisible Computing open sourceembeddedactiveARM7-9, i386, h8, mips, Trimedia, eCog1
mLithOSembedded, industrialactiveLEON2-3-4, x86,
MOTORCORTEXserver: closed, clients: open sourceembedded, industrialactivex86, ARM,
MP/Mclosed general purpose, industrialdefunct8080, Z80, 8086Digital Research
MQXcomplimentary source code availableembeddedactiveFreescale Power, ColdFire, Kinetis Cortex ARM, List of Freescale products
MERTinactivePDP-11
Multiuser DOSclosedgeneral-purpose, industrialdefunct386Digital Research/Novell, Concurrent Controls, Datapac, IMS
Nano-RKopen sourceembedded, WSNactiveAVR, MSP430
Neutrinosome source code providedmicrokernelactiveARM, MIPS, PPC, SH, x86, XScale
NI Linux Real-Timedeveloped from open sourcedata acquisition and process controlactiveNational Instruments CompactRIO controllers
nOSopen sourceembeddedactiveAVR, MSP430, Cortex-M0-M3-M4, M16C, RX600, PIC24, Win32, POSIX, STM8
Nucleus RTOSsource code providedembeddedactiveARM, PowerPC, MIPS32-16e, microMIPS, ColdFire, SuperH
NUFRopen sourceembeddedactiveARM, MSP430, MSP430X
Nut/OSopen sourceembedded, industrialactiveAVR, AVR32, ARM7, ARM9, Cortex-M3
NuttXopen sourceembedded, small footprintactiveLinux 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
OpenEPOSopen sourceembeddedactiveARM, x86, AVR, MIPS, PowerPC
OS20closedembedded maintenance onlyST20
OS2000embeddedactiveMIPS, KOMDIV-32, KOMDIV-64, Intel BSPs
OS21source code providedembedded activeST40/SH4, ST200, ARM
OS4000closedprocess controlmaintenance onlyGEC 4000 series
OpenRTOSsource code availableembeddedactiveSame as FreeRTOS
OSAopen sourceembeddedactivePIC10-PIC24, AVR 8-bit, STM8
OSEavailable to customersgeneral purposeactiveARM, PowerPC, x86, TI OMAP, …
OS-9available to customersembeddedactiveARM-strongARM, MIPS, PowerPC, SuperH, x86/Pentium, XSCALE, Motorola 6809, 680x0, SPARC
OSEKspecificationembeddedactiveengine control units, better refer to
Partikleembedded, industrialactiveLEON2-3-4, x86,
Phar Lap ETS
PaulOSopen sourceembedded
PICOS18open sourceembeddedPIC18
picoOSopen sourceembeddedmaintenance6502, 80x86, ARM7, AVR, PowerPC, Cortex-M, MSP430, PIC32,
Piko/RTopen sourceembeddedactiveARM Cortex-M3/M4
Pharosopen sourceembedded, industrial, safety criticalactiveARM, RISC-V
Phoenix-RTOSopen sourceembeddedactiveARMv7 Cortex-M, ARMv7 Cortex-A, IA-32, RISC V
PikeOSavailable to customerscertifiable safety & security, embedded virtualisationactivePPC, x86, ARM, MIPS, SPARC-LEON,
Portossource code providedembedded, small footprintactive
POKopen sourceembeddedactivex86, PowerPC, SPARC
PowerTV
Prexopen sourcemicrokernelactiveARM, IA-32
Protothreadsopen sourcegeneral purposeactiveArchitecture independent
pSOSdiscontinued680x0
QNXgeneral purpose, medical devicesactiveIA-32, MIPS, PowerPC, SH-4, ARM, StrongARM, XScale
QPdualMCU, DSC, DSP SoCactiveARM7/9, ARM Cortex-M3-M0, MSP430, TMS320C28x, AVR, AVRXmega, ColdFire, 68HC08, M16C/R8C, H8, 8051, 80251, PIC18, PIC24/dsPIC33, Nios II, PSoC1
Questopen sourceembedded / mixed-criticalityactivex86
:ru:Kaspersky OS|Kaspersky OSsafety critical, virtualizationactive
Data General RDOSgeneral purposedefunctData General Nova, Data General Eclipse
ReaGOSclosed, available with licenseembeddedactivex86, ATmega, ARM, portable
REAL/32closedgeneral-purpose, industrialactive386IMS
RedHawk Linux closed, available with licenseHard Real-Time: server, workstation; embeddedactivex86, ARM
Real-time Linux open sourcegeneral purposeactivesame as Linux,,
REX OSclosed, available with licenseembeddedinactiveARM:ja:REX OS
RIOTopen sourceembeddedactiveARM, MSP430, AVR, x86, RISC-V
RMXclosedembeddeddefunct8080, 8086, 80386 or higher
RODOSsource code providedembeddedactiveARMv7, AVR32, PowerPC 405, sparc64
Platforms: , RaspberryPi, STM32
On top of OS: Linux, Windows, MacOS, FreeRTOS, RTems
RSX-11historicPDP-11n/a
RT-11general purposedefunctPDP-11n/a
RTAIopen sourcegeneral purposeactivex86, x86-64, PowerPC, ARM, m68k
RTEMSopen sourceembeddedactiveARM, Blackfin, ColdFire, TI C3x/C4x, H8/300, x86, 68k, Milkymist SoC, MIPS, Nios II, PowerPC, SuperH, SPARC, ERC32, LEON, Mongoose-V
RTLinuxopen sourcegeneral purposeinactivesame as Linuxn/a
RTOS-32, royalty freesource availableembeddedactivex86
RT-Threadopen sourceembeddedactiveARM, ARM Cortex-M0-M3-R4-M4-M7, IA-32, AVR32, Blackfin, nios, PPC, M16C, MIPS, MicroBlaze, V850, unicore32,,
RTXC Quadrossource availableembeddedactiveARM - Atmel/Freescale/NXP/ST/TI, Blackfin, 680x0-ColdFire, PowerPC, StarCore, TI-Luminary Stellaris, TI OMAP, XScale
RTX, RTX64closedMS Windows extensionactivex86, x86-64
RTX Keil Real-Time Operating System, royalty freesource availableembeddedactiveARM
Ruffclosedembedded, general purpose, industrial, IoTactiveARM, MIPS, x86
RX116embedded, industrialdefunctNEC V20, NEC V30, NEC V40, NEC V50first ITRON 1 compatible 16-bit RTOS
RX616safety critical, embedded, industrialdefunctNEC V60, NEC V7032-bit ITRON compatible
RX-UX832embedded, industrial, general-purposedefunctNEC V60, NEC V7032-bit Unix-like RTOS
SafeRTOSsource code & Design Assurance Pack availableembedded, safety criticalactiveSame as FreeRTOSSame as FreeRTOS
SCIOPTAclosed, source availableembedded, safety relatedactiveARM, Cortex-M0-M3-M4, Cortex-R4, Cortex-A5, Cortex-A7, Cortex-A9, Cortex-A53, XScale, Renesas RX100, RX200, RX600, RX700, PowerPC, ColdFire, HCS12, M16C, Windows, Aurix TC2xx, BlackFin BF52x, BF70x
scmRTOSopen sourceembeddedactiveARM, Cortex-M3, Blackfin, MSP430, AVR, STM8
SDPOSopen sourceembeddedactiveARM, Cortex-M3, Blackfin, PIC18, PIC24, i386 win32/linux synthetic targets
SHaRKopen sourceinactive
silRTOSopen sourceembeddedactiveARM, Cortex-M3 Cortex-A9 ARM-11MP, Blackfin, MIPS, AVR
Simbaopen sourceembeddedactive, betaArduino Nano, Arduino Mega, Arduino Due, ESP8266, ESP32, cygwin/linux
SimpleAVROSopen sourceembeddedactive, betaAVR onlyn/a
SINTRAN IIINorsk Data computersn/a
SOOS Projectopen sourceembeddedactive, betaH8/300
StateOSopen sourceembedded, small footprintactiveARM Cortex-M, STM8
Stratify OSopen sourceembeddedactiveARM Cortex-M3, M4
Symbian OSopen sourceembeddeddefunctARM
Talon DSP RTOSembedded DSPactiveTMS320
TargetOSavailable to customersembeddedactiveARM, Cortus, Freescale ColdFire, PowerPC
T-Kernelsource availableembedded RTOSactiveARM, MIPS, SH, more
THEOS
ThreadXavailable to customersactiveARC, 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
open sourceembeddedactiveARM
TI-RTOS Kernel open sourceembeddedactiveMostly Texas Instruments: MSP430-432, C2000-5000-6000, TI's ARM families, SimpleLink Wireless CC2xxx-CC3xxx
Tock OSopen sourceembeddedactiveARM Cortex, RISC-Vhttps://www.tockos.org
Trampoline Operating System open sourceembeddedactiveArduino Uno, Arduino Mega, XPlainedPro, Raspberry Pi 2 Model B, Olimex LPC-L2294-1MB, Teensy31, XPC56XX EVB + XPC56XL MINI-MODULE, ZedBoard, STM32F4DISCOVERY, Nucleo-32, Cortex-M3 - SmartFusion2, virt-V7
TNKernelopen sourceembeddedactiveARM, PIC24-32-dsPIC, HCS08, STM32
TNeoopen sourceembeddedactiveCortex-M0-M0+-M1-M3-M4-M4F, PIC24-32-dsPIC
Transaction Processing Facilitygeneral purposeactiveIBM System/360 derivatives
TRON projectmixedmixedactiveany: is a specification, not an implementation
TUD:OSopen sourceactiveARM, IA-32, x86-64
Unison RTOSopen sourceMCU, DSC, DSP SoC, FPGAactivePic32, ARM Cortex, X86, RISC-V
Zephyropen sourceembeddedactiveARM, x86, x86-64, ARC, RISC-V, Nios II, Xtensa