More blogs in Arm Community blogs
Tags
Actions
Related blog posts
Related forum threads

Real-Time Operating Systems (RTOS)

Alban Rampon

All major vendors of Real-Time Operating Systems (RTOS) support ARM architecture.

Many embedded systems require software to respond to inputs and events within a defined short period. Such systems can be categorized as hard real-time, where missing a response deadline is unacceptable (for example an anti-lock braking system), and soft real-time, where hitting a deadline is desirable but not critical. In both types of system, a degree of determinism is important.

RTOS is designed to control an embedded system and deliver the real-time responsiveness and determinism required by the controlled device. Applications run under the control of the RTOS, which schedules allocated CPU time.

In modern systems, a RTOS consists not only of a real-time kernel, but also higher-level functions such as device management (USB, UART, Ethernet, LCD, etc.), file systems, protocol stacks (CAN, TCP/IP, HTTP, etc.) and graphical user interfaces (GUI).

ARM Advantage

The ARM architecture is particularly well suited to the real-time and deterministic requirements of embedded systems, and the implementation of RTOS running on those systems:

  • Small code footprint, allowing an RTOS to run from onboard memory
  • Fast interrupt response to reduce context switching overhead
  • Semaphore support via exclusive load-and-store instructions
  • SVC instructions and exceptions to support privileged state operation for the RTOS kernel
  • Separate stack pointers for each processor mode for easier memory management
  • Sleep modes to minimize power consumption

Whatever your application, you are sure to find a comprehensive list of RTOS vendors who support the ARM architecture.

RTOS Vendors

The ARM architecture is supported by all popular RTOS vendors in the embedded market. Below is a table showing the RTOS companies, their products, and an indication of which ARM processor families they currently support:

Company RTOS Cortex- Classic
A R M ARM11 ARM9 ARM7
Altreonic OpenComRTOS •
American Megatrends MegaRAC •
AVIX-RT AVIX •
B Labs Codezero Embedded Hypervisor • • •
CMX Systems CMX-RTX • • • • • •
Code Time Technologies Code Time RTOS •
CooCox CooCox CoOS •
Dalian uLoong μTenux Open Source Embedded OS • • •
DDC-I Inc HeartOS • •
eCosCentric eCos • • • • • •
eForce µC3 • •
Enea Software AB OSE • • • •
eSOL eT-kernel, PrKERNEL • • • •
Evidence SRL ERIKA Enterprise (OSEK) • •
Express Logic ThreadX • • • • • •
FreeRTOS.org FreeRTOS • • •
Green Hills Software INTEGRITY, VelOSity • • • • • •
Hopen Software Eng Co Ltd Hopen RTOS • • • •
HYCTRON Electronic Ltd Embedded OS • •
KADAK AMX RTOS • • •
Keil Keil RTX • • •
LynuxWorks LynxOS, Blue Cat • • •
Mentor Graphics Nucleus ReadyStart • • • • • •
Micrium µC/OS-III • • • •
Micro Digital Inc SMX RTOS • • • •
OBP Research ReaGOS • • •
OpenSynergy GmbH COQOS • •
Pengutronix OSELAS • • • • •
Phoenix Technologies HyperSpace • •
QNX Software Systems Neutrino • • •
Quadros Systems RTXC Quadros • • • • •
Quantum Leaps QP-nano • • •
Radisys Microware OS-9 • •
RISC OS Ltd RISC OS • •
Rowebots Research Unison v4 •
rt-labs AB rt-kernel • • •
RT-Thread.org RT-Thread RTOS • • •
SCIOPTA SCIOPTA • • • • • •
Segger EmbOS • • • • •
Sierraware SierraOS • •
Semihalf FreeBSD • •
SYSGO PikeOS • •
Umicos Catapult RTOS • •
Unicoi Systems Fusion RTOS •
Wind River VxWorks • • • •
Wittenstein OpenRTOS, SafeRTOS • • •
Anonymous
Embedded blog