Best Real-Time Operating Systems (RTOS) for Linux of 2025

Developed in collaboration with top chip manufacturers over a span of 15 years, FreeRTOS is now downloaded approximately every 170 seconds and stands as a top-tier real-time operating system (RTOS) tailored for microcontrollers and small microprocessors. Available at no cost under the MIT open source license, FreeRTOS encompasses a kernel along with an expanding collection of IoT libraries that cater to various industries. Prioritizing reliability and user-friendliness, FreeRTOS is renowned for its proven durability, minimal footprint, and extensive device compatibility, making it the go-to standard for microcontroller and small microprocessor applications among leading global enterprises. With a wealth of pre-configured demos and IoT reference integrations readily available, users can easily set up their projects without any hassle. This streamlined process allows for rapid downloading, compiling, and quicker market entry. Furthermore, the ecosystem of partners offers a diverse range of options, including both community-driven contributions and professional support, ensuring that users have access to the resources they need for success. As technology continues to evolve, FreeRTOS remains committed to adapting and enhancing its offerings to meet the ever-changing demands of the industry.

Arm Mbed OS is an open-source operating system tailored for IoT applications, providing all the essential tools for creating IoT devices. This robust OS is equipped to support smart and connected products built on Arm Cortex-M architecture, offering features such as machine learning, secure connectivity stacks, an RTOS kernel, and drivers for various sensors and I/O devices. Specifically designed for the Internet of Things, Arm Mbed OS integrates capabilities in connectivity, machine learning, networking, and security, complemented by a wealth of software libraries, development boards, tutorials, and practical examples. It fosters collaboration across a vast ecosystem, supporting over 70 partners in silicon, modules, cloud services, and OEMs, thereby enhancing choices for developers. By leveraging the Mbed OS API, developers can maintain clean, portable, and straightforward application code while benefiting from advanced security, communication, and machine learning functionalities. This cohesive solution ultimately streamlines the development process, significantly lowering costs, minimizing time investment, and reducing associated risks. Furthermore, Mbed OS empowers innovation, enabling developers to rapidly prototype and deploy IoT solutions with confidence.

The SCIOPTA architecture is meticulously crafted to ensure outstanding real-time performance while maintaining a compact size. Its internal data structures, memory management, interprocess communication, and time management are all finely tuned for efficiency. Functioning as a pre-emptive real-time kernel, SCIOPTA allows interrupts to be handled at any moment, even during kernel execution. This operating system relies on a message-based model, providing a robust array of system calls for effective resource management. With standardized processes and interprocess communication protocols, SCIOPTA promotes clear system designs that are both easy to implement and maintain. The well-defined messaging system allows processes to communicate seamlessly and enables the grouping of processes into modules, making SCIOPTA particularly advantageous for collaborative efforts in large projects. The streamlined design significantly accelerates time-to-market, enhancing overall project efficiency. Moreover, the direct message passing capability between processes facilitates not only interprocess communication but also synchronization, further optimizing system performance.

Since its inception in 1980, QNX has been the choice of thousands of enterprises seeking to implement real-time operating systems that deliver an optimal blend of performance, security, and reliability for their mission-critical operations. Central to QNX's innovation is the QNX Neutrino® Real-time Operating System (RTOS), which is a comprehensive solution that facilitates the development of next-generation products across various sectors where dependability is paramount, such as automotive, healthcare devices, robotics, transportation, and industrial embedded environments. Thanks to its microkernel architecture, QNX ensures that a failure in one component does not disrupt the operation of others or compromise the kernel, as the malfunctioning part can be simply halted and restarted without negatively impacting the overall system. The QNX Neutrino RTOS stands out by providing the determinism unique to real-time operating systems, employing methods like adaptive partitioning to ensure that essential processes receive the necessary processing cycles to perform their tasks promptly, all while sustaining the performance expectations of intricate embedded systems. This combination of features makes QNX Neutrino RTOS a preferred choice for developers looking to create robust and resilient applications. As technology continues to evolve, the adaptability of QNX's offerings ensures that they remain at the forefront of real-time operating system solutions.

Deos™, developed by DDC-I, is a safety-critical real-time operating system (RTOS) that has been rigorously verified according to DO-178C/ED-12C Design Assurance Level A (DAL A) standards specifically for avionics applications. This RTOS supports ARINC 653 APEX and rate monotonic scheduling (RMS), and it is designed to meet the FACE Safety Base Profile requirements. Since its initial verification by Transport Canada in 1998, it has been a trusted solution in the aviation industry, with its certification allowing it to operate in tens of thousands of aircraft. Over the past two decades, Deos has adapted and evolved to incorporate new processors and features, demonstrating its flexibility and resilience. It has also undergone successful audits by a range of global certification authorities, including the FAA, ENAC, JAA, EASA, and CAAC, as well as by designated engineering representatives from various airframe and avionics suppliers, ensuring its continued compliance with industry standards. Its proven track record and ongoing development make it a pivotal component in modern aviation safety systems.

INTEGRITY employs hardware memory protection to effectively isolate and safeguard embedded applications. By utilizing secure partitions, it ensures that every task has the necessary resources to operate correctly while simultaneously shielding the operating system and user tasks from erroneous and harmful code, which encompasses threats like denial-of-service attacks, worms, and Trojan horses. To facilitate developers in expediting their product creation, Green Hills Software provides a comprehensive suite of middleware that has been integrated and validated for use with INTEGRITY, featuring options like FFS, FAT, NFS, and journaling file systems, alongside both IPv4 and IPv6 host and routing networking stacks, as well as a FIPS 140-2 certified Suite B embedded encryption library, among other tools. Notably, each middleware package has undergone pre-integration and rigorous testing to ensure it operates smoothly with INTEGRITY’s sophisticated RTOS features. Furthermore, Green Hills Software also presents tailored platforms for various industries, which encompass a fully integrated ecosystem that includes the INTEGRITY RTOS along with essential development tools, aiming to streamline the development process even further. This cohesive approach not only boosts efficiency but also enhances the overall security of embedded applications.

The MQX real-time operating system (RTOS) delivers excellent real-time capabilities while maintaining a compact and customizable footprint. This RTOS is seamlessly integrated with NXP's 32-bit MCUs and MPUs and comes with essential device drivers commonly utilized in embedded applications. Designed with a contemporary, component-oriented microkernel architecture, the MQX RTOS allows engineers to tailor features, size, and performance by selectively integrating components, thus adhering to the stringent memory limitations typical of embedded systems. Remarkably, it can be set up to use as little as 8 KB of ROM and 2.5 KB of RAM on the Arm Cortex M4, accommodating the kernel, two task applications, one lightweight semaphore, the interrupt stack, queues, and the memory manager. This configuration ensures a complete RTOS core is available while offering additional optional services as needed. By linking components only when required, the system effectively avoids unnecessary memory bloat from unused functions. Moreover, key components are offered in both standard and lightweight configurations, providing further flexibility regarding size, RAM and ROM usage, and performance options, making it a versatile choice for various applications.

OpenWrt is an adaptable GNU/Linux distribution designed specifically for embedded devices, especially wireless routers. In contrast to many other router distributions, OpenWrt is engineered from the ground up to function as a comprehensive and easily customizable operating system for embedded systems. This design philosophy ensures that users can access all essential features without unnecessary bloat, thanks to its reliance on a modern Linux kernel. Rather than offering a single, unchangeable firmware, OpenWrt features a fully writable filesystem accompanied by optional package management. This versatility liberates users from the limitations imposed by manufacturers regarding application choices and configurations, allowing for tailored modifications to meet any specific application needs. Furthermore, for developers, OpenWrt serves as a robust framework that enables the creation of applications without the necessity of building an entire firmware image or distribution around them, thus simplifying the development process. Ultimately, this makes OpenWrt an appealing choice for both end-users and developers alike.

Enea OSE is a powerful and efficient real-time operating system specifically designed for multi-processor environments that demand genuine deterministic real-time performance and exceptional reliability. By streamlining the development process, it improves system reliability and minimizes long-term maintenance expenses across a diverse array of applications, including wireless technology, automotive solutions, medical devices, and telecom infrastructure. Tailored for communication and control systems, Enea OSE excels in delivering high performance alongside stringent real-time requirements. Its widespread implementation spans several sectors, including telecommunications, industrial automation, and embedded systems, ensuring its relevance in modern technology. Notably, the Enea OSE multicore kernel, which has garnered two prestigious awards, combines the user-friendly aspects of Symmetric Multi-Processing (SMP) with the scalability and deterministic benefits of Asymmetric Multi-Processing (AMP), all while maintaining the high performance characteristic of bare metal operation. This unique architecture makes Enea OSE a compelling choice for developers seeking reliability and efficiency in their multi-core applications.

PikeOS is a separation kernel-based hypervisor that supports multiple partitions for many operating systems and applications. It allows you to create smart devices for the Internet-of-Things. PikeOS is the best choice for systems that require protection against Cyber-Security attack due to its separation kernel approach. It is widely used in millions of edge and IoT systems. However, it has also been deployed in critical communications infrastructures. PikeOS combines virtualization and real time with unique technologies that have never been seen before. It allows you to move multiple complex embedded circuit boards into one hardware. It is also able to handle new hardware concepts like Big-SoCs that have multiple heterogeneous cores. PikeOS can run on multiple architectures and support processors that have a memory management unit (MMU).

Ranging from basic embedded environmental sensors and LED wearables to advanced embedded controllers, smartwatches, and IoT wireless applications, this system incorporates configurable architecture-specific stack-overflow protection, kernel object and device driver permission tracking, and thread isolation enhanced by thread-level memory protection across x86, ARC, and ARM architectures, as well as userspace and memory domains. For systems lacking MMU/MPU and those limited by memory capacity, it enables the integration of application-specific code with a tailored kernel to form a monolithic image that can be loaded and run on the hardware of the system. In this setup, both the application and kernel code operate within a unified address space, facilitating efficient resource utilization and performance optimization. This design ensures that even resource-constrained environments can effectively leverage complex applications and functionalities.

Wind River's eLxr Pro is a robust, commercial-grade Linux solution tailored for a wide range of cloud-to-edge applications, capable of handling critical workloads such as artificial intelligence, machine learning, and computer vision tasks. This solution is derived from the open-source eLxr distribution and delivers adaptable, long-term support alongside continuous security monitoring and updates. It guarantees compatibility with various hardware accelerators and meets necessary industry compliance standards. Additionally, eLxr Pro enhances business operations by offering specialized consulting services and performance improvements, enabling organizations to efficiently scale their edge computing capabilities while effectively managing expenses, ensuring security, and optimizing resource use. By integrating these features, eLxr Pro positions businesses to thrive in an increasingly digital landscape.