Comparison of Real-Time Operating System (RTOS)


Select a RTOS

Free RTOS

 OS name 
 website 
 kernel ROM 
 Kernel RAM 
 target processor 
 network 
 standards 
 schedeling policies 
 multiprocessor 
 multiprocess 
 garanteed maximum 
 interrupts latency 
 Typical thread  
 switch latency 
 minimum RAM  
 per queue 
 minimum RAM  
 per thread 
 development host 
 priority inversion  
 avoidance mecanism 
 type of licence 
 ChorusOS 
chorusOS website
 150KB 
 unknown 
 x86, 
 PPC 
 nTCP/IP and UDP/IP 
 POSIX 
 pre-emptive FIFO,
Round-Robin,
multi-class scheduling
 yes 
 yes 
 Interrupt Handler Entry : 0.36Ás 
 Interrupt Handler Return : 0.3Ás 
 Between 09 and 2.2Ás 
 unknown 
 0.5KB 
 X86, 
 Linux, 
 Solaris 
 mutex, 
 other mechanism under Linux 
 Linux Open Source, 
 Sun Public License Lite Version 1.0 
 ERIKA 
erika website
 2kB for H8 
 Hundreds of bytes 
 Hitachi H8, 
 Lego Mindstroms 
 Lego Mindstorms infrared 
 custom wireless RF network 
 C library, 
 interface similar to OSEK/VDX 
 fixed priority DM scheduling algorithm 
 with a Non-Preemptive protocol 
 for accessing mutually exclusive shared resources 
 yes 
 yes 
 2Ás on ARM 16Mhz 
 5-9Ás on ARM 
 dep 
 dep 
 Linux, 
 Windows 
 Yes 
 GNU GPL license for education, 
commercial for the others
 eCos 
eCos website
 <1.25kB 
 ~300KB
 <0.6kB (targ.dep), 
 config dependent 
 x86, 
 PPC 
 TCP/IP, FTP, SNMP, PPP, 
 Telnet, Bootp, DNS, DHCP, 
 IPV6, TFTP, HTTP, SNTP
 ISO C, POSIX.1a, 1b, 1c, 1d subset, 
 uITRON, EL/IX Level I&II (deprecated) 
 FIFO, 
 Round-Robin, 
BitMap 
 yes 
 no 
 10.42 us (soft) 
 0.87 us (target dep) 
 16 bytes 
 56 bytes (exc.stack) 
 Linux, 
 Windows 
 Priority inheritance, 
 priority ceilings 
 open source 
 EROS 
EROS website
 unknown 
 unknown 
 unknown 
 TCP/IP 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 open source, 
 GPL 
 fiasco 
To the top
fiasco website
 100kB 
 1MB 
 x86, 
 ARM 
 unknown 
 L4, 
 Experimental support for the linux RT interface
 Round-Robin, 
 Quality-Assuring Scheduling
 no 
 yes 
 Syncronous : 900 cycles on Pentium 
 Asyncronous : 2000 cycles on Pentium 4 
 Worst case with Pentium 4 on x86 : 33Ás 
 unknown 
 2kB 
 Linux 
 yes 
 GNU GPL 
 FreeRTOS 
FreeRTOS website
 4.4Kbytes with Gcc 
 <500, 
 depends on the config
 x86, 
 ARM 
 TCP/IP, 
 Ipv6 
 Not POSIX compliant 
 Round-Robin, 
 preemption
 no 
 no 
 dep 
 dep 
 45 
 + queue storage area 
 20 + 
 the task stack size 
 Windows 
 No, 
 A priority algorithm will take up 
 processing time within the kernel 
 Free source code 
MaRTE OS 
MaRTE OS website
 unknown 
 unknown 
 x86 
 TCP/IP 
 POSIX 
 multithreading Pthread, 
 FIFO, 
 Round-Robin, 
 Sporadic Server
 no 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux 
 unknown 
 GNU GPL 
 menuet 
menuet website
 Don't use 
 32MB 
 x86 
 TCP/IP 
 None 
 Pre-emptive multitasking, 
 multithreading, 
 ring-3 protection, 
 FIFO 
 no 
 no 
 TSSes 
 = moderation of latency 
 calculate the cost of 
 Loading 2 TSSes 
 fixes sized tables 
 fixes sized tables 
 use new computers 
 no 
 GPL 
 oberon 
oberon website
 1.44MB 
 unknown 
 x86, 
 PPC 
 TCP/IP 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux, 
 Windows 
 unknown 
 open source 
 RTAI 
RTAI website
 1MB 
 68MB 
 x86, 
 PPC, 
 ARM 
 TCP/IP 
 POSIX 1.b, 1.c, 1003.13, 
 ISO C 
 Round-Robin, 
 preemptive, 
 FIFO, 
 Rate-Monotonic 
 yes 
 yes 
 <20Ás 
 10Ás 
 unknown 
 unknown 
 Linux 
 yes 
 free 
 RTEMS 
To the top
RTEMS website
 >=1MB 
 >=1MB 
 x86, 
 PPC, 
 ARM 
 UDP, 
 TCP/IP 
 POSIX 1003.1b, 
 uITRON 3.0 API 
 priority-based pre-emptive scheduling, 
 Rate-Monotonic, 
 Priority inheritance 
 yes 
 yes 
 ~< 1Ás 
 unknown 
 unknown 
 unknown 
 Linux, 
 Unix, 
 MS DOS, 
 Windows 
 priority inheritance, 
 priority ceilings 
 free, 
 open source 
 RTLinux 
RTLinux website
 150KB 
 8MB 
 x86, 
 PPC, 
 ARM 
 TCP/IP 
 POSIX 1003.13, 1b, 1c, 1d, 1j, 
 ISO C 
 Prioritized FIFO, 
 extensible scheduler 
 yes 
 yes 
 ~20Ás 
 ~20Ás 
 unknown 
 unknown 
 Linux 
 lock-free data structures, 
 priority ceiling 
 free 
 S.Ha.R.K 
S.Ha.R.K website
 60KB -> infinity 
 2MB 
 ARM, 
 PPC 
 UDP 
 POSIX 1003.13, 
 PSE52 
 Rate-Monotonic, EDF, EDFACT - EDF, 
 Round-Robin, 
 Round-Robin SOFT, 
 Round-Robin2, 
 SLSH, DUMMY, Static 
 no
 no, 
 Multithread 
 3Ás on a celeron 360 Mhz 
 5-10Ás on a celeron 360 Mhz 
 unknown 
 unknown 
 Linux, 
 Windows 
 yes 
 free 
 TinyOS 
TinyOS website
 432B 
 46B 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux RedHat 9.0, 
 Windows 2000, 
 Windows XP
 unknown 
 free 
 Phoenix-RTOS 
To the top
Phoenix-RTOS website
 unknown 
 unknown 
 ARM, 
 PPC, 
 IA32 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 free 

Others RTOS

 OS name 
 website 
 kernel ROM 
 Kernel RAM 
 target processor 
 network 
 standards 
 schedeling policies 
 multiprocessor 
 multiprocess 
 garanteed maximum  
 interrupts latency 
 Typical thread  
 switch latency 
 minimum RAM  
 per queue 
 minimum RAM  
 per thread 
 development host 
 priority inversion 
 avoidance mecanism 
 type of licence 
 Nucleus RTOS 
To the top
Nucleus RTOS website
 13 KB 
 unknown 
 ARM, 
 MIPS, 
 PPC 
 TCP/IP, 
 IPv4, IPv6 
 ANSI "C", 
 POSIX, 
 C++, 
 ÁITRON 
 unknown 
 yes 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 royalty-free 
 $2995 USD 
 OSEK-VDX 
OSEK-VDX website
 unknown 
 unknown 
 8bits, 16bits, 
 32bits 
 unknown 
 unknown 
 pre-emption 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux 
 yes 
 free licence 
 QNX 
QNX website
 unknown 
 unknown 
 MIPS, PPC, SH-4, 
 ARM, StrongArm, 
 XScale, x86
 IPv4, IPv6, IPSec, 
 FTP, HTTP, 
 SSH, Telnet 
 POSIX.1 
 FIFO, 
 Round-Robin 
 yes 
 yes 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux, 
 DOS 
 yes, 
 priority ceiling 
how to buy
 PikeOS 
PikeOS website
 150kB 
 150kB 
 MIPS, 
 PPC, 
 x86 
 unknown 
 POSIX, 
 ARINc-653, 
 native 
 time and priority 
 driven scheduling 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux, 
 Windows XP SP2, 
 windows 2000 SP4 
 unknown 
how to buy
 Talon DSP RTOS 
Talon DSP RTOS website
 16kB to 1MB 
 16kB to 1MB 
 blackhawk-dsp 
 family 
 unknown 
 POSIX 1003 
 .1/.4a/.4b/.4c 
 priority 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux 
 Windows 
 mutex 
how to buy
 Fusion RTOS 
To the top
Fusion RTOS website
 1 - 1.5KB
 <30 words for kernel 
 <15 words per task 
 Motorola DSP 5680, 
 Motorola DSP 56800E, 
 Motorola StarCore, 
 Analog Devices Blackfin 
 ARM7/9 
 depends of 
 your network 
 modules
 POSIX 
 priority based, 
 preemption 
 no 
 multitasking 
 unknown 
 190 Cycles 
 4.75 Ásec @ 40 MIPs
 unknown 
 unknown 
 unknown 
 yes 
sales@unicoi.com
 VXworks 
VXworks website
 unknown 
 unknown 
 32bit, 64bit, 
 multicore 
 IPsec, IKE, 
 SNTP, 
 wireless LAN 
 POSIX, 
 ARINC 653-1, PRE ALIGN=CENTER> DO-178B
 unknown 
 yes 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 Linux, 
 Windows 
 unknown 
 open source License 
 Administrator Essentials 
 ISIT 
ISIT website
 unknown 
 unknown 
 AVR, S08, S12, S12X, 
 ColdFire, ARM7, ARM9, XSCALE, 
 PowerPC, MIPS, M16C, M32C, 
 XC167, DSP 
 TCP/IP 
 no standard 
 unknown 
 no 
 Multitasking 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 RTOS-32 
RTOS-32 website
 16kB 
 16kB 
 for protected mode 
 32/64-bit x86 CPUs 
 BOOTP, RARP, ARP, 
 ICMP, UDP, TCP, 
 DNS, NAT, NATP 
 Win32 API 
 Round-Robin, 
 pre-emption, 
 Priority Ordered Queues, 
 time slice
 yes 
 Multitasking 
 unknown 
 unknown 
 unknown 
 unknown 
 Windows 
 no 
 royalty-free 
 LynxOS RTOS 
LynxOS RTOS website
 unknown 
 Up to 2GB 
 Motorola/IBM PPC 
 Freescale Power QUICC 2/3 
 Intel architecture family 
AMCC 4xx PPC family
 Pv4, IPv6 TCP, UDP, 
 ICMP, IGMP, ARP, RARP, 
 DHCP, NAT, RPC, NTPv3 
 POSIX 1003.1-2003 
 PSE 53/54 
 UNIX 
 FIFO, 
 Priority Quantum, 
 Round-Robin, 
 Non-preemptive
 no 
 Symetric Multiprocessing
 unknown 
 unknown 
 unknown 
 unknown 
 Linux 
 unknown 
 LynuxWorks 
 Public License 
 CMX RTOS 
To the top
CMX RTOS website
 unknown 
 unknown 
 Microcontroler, 
 Microcomputer, 
 DSP 
 TCP/IP 
 (add module) 
 no standard 
 pre-emption, 
 time slice scheduling 
 no 
 multitasking 
interrupt latency
context switch
 unknown 
 unknown 
 unknown 
 unknown 
price
 SALVO RTOS 
SALVO RTOS website
 unknown 
 unknown 
 8051 family 
 ARM ARM7TDMI and Cortex-M3 
 Atmel: AVR, MegaAVR 
 Motorola: M68HC11 
 TI: MSP430, TMS320C2000 DSPs 
 Microchip: PIC12|14000|16|17|18 
 PICmicro MCUs, PIC24 MCUs, 
 dsPIC DSCs, PIC32 MCUs 
 unknown 
 no standard 
 unknown 
 no 
 multitasking 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 royalty-free 
price
 SMX RTOS 
SMX RTOS website
 37 to 52 KB 
 unknown 
 ARM7/9, ColdFire, 
 PowerPC, x86 
 unknown 
 no standard 
 pre-emption, 
 Round-Robin (same priority) 
 no 
 multitasking 
 unknown 
 unhnown 
 unknown 
 unknown 
 Linux, 
 Windows XP 
 yes, 
 add mutex 
 royalty-free
 license agrement 
 INTEGRITY 
To the top
INTEGRITY website
 unknown 
 unknown 
 unknown 
 IPV4, IPV6 
 POSIX.1 
 Rate-Monotonic Analisys 
 unknown 
 multitasking 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 yes 
 royalty-free 
 MQX RTOS 
MQX RTOS website
 6 KB 
 unknown 
 ARC600, ARC700, 
 can be configured for others 
 famillies processors
 TCP/IP, 
 serial connection 
 no standard 
 scheduler task /PRE>
 creation/destruction 
 no 
 multitasking 
 500 MHz ARC 700: 
 ~0.30 Ásec
 under 200 cycles 
 500 MHz ARC 700: 
 ~0.42 Ásec 
 unknow 
 unknow 
 Windows 
 mutex 
 using their standard 
 private commercial 
 fee-based licensing terms 
 AMX RTOS 
AMX RTOS website
 depends of the 
 microprocessor: 
 [10kB, 24kB] 
 depends of the 
 microprocessor: 
 [128B, 1kB] 
 Intel: 80186/188 (EA/EB/EC/XL), 
 Intel386, Intel486, Pentium 
 AMD: Am186/188 (EM/ES), Am386 (SE/DE) 
 VAuto-mation: Turbo86, Turbo186 
 unknown 
 no standard 
 Preemptive, 
 priority based task scheduler
 unknown 
 multitasking 
 depends of the 
 microprocessor:
 [2.2Ás, 21.3Ás] 
 averaging 100 such cycles 
 depends of the 
 microprocessor:
 [0.5Ás, 26.6Ás] 
 depends of the 
 microprocessor:
 [128B, 1kB] 
 depends of the 
 microprocessor:
 [128B, 1kB] 
 unknown 
 yes 
 negociate: 
amxsales@kadak.com
 RTXC quadros 
To the top
RTXC quadros website
 unknown 
 unknown 
 ARM 7/9/11 CORTEX M3, /PRE>
 blackfin, coldfire, /PRE>
 PPC, DSP56F800, MSC71xx/81xx 
 infineon C16x, TI C54x/C55x 
 "RXTC quadusb" have: USB 
 "RXTC quadnet TCP/IP" have: 
 TCP/IP, UDP, DNS, IPV4, 
 IPV6, DHCP/BOOTP, IGMP, 
 HTTP, POP3, SNTP, 
 SNMP, FTP, TFTP, 
 Telnet, SSl, IPsec/IKE 
 no standard 
 cooperaive, Round-Robin, 
 pre-emptive, time-sliced 
 yes, configuration: 
 RTXC/mp
 multitasking 
 unknown 
 unknown 
 unknown 
 unknown 
 unknown 
 mutex 
 negociate: 
sales@quadros.com
To the top
Last update: 2013 May 31
Contact: Yves.Sorel@inria.fr