FreeRTOS vs ThreadX vs Zephyr: The Fight For True Open Source RTOS

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FreeRTOS vs ThreadX vs Zephyr: The Fight For True Open Source RTOS

From scheduling tasks to enabling high-level languages, one of the most important components of today’s embedded systems is the real-time operating system (RTOS).

Two real-time operating systems dominate the market: FreeRTOS and ThreadX. But, in recent years, Amazon acquired the former and Microsoft the latter, with each included as part of their respective IoT cloud system packages. Another one is on the rise: Zephyr. 

FreeRTOS vs ThreadX vs Zephyr

Now, critics question if either of the systems will remain truly open source, especially since both parent companies have previously engaged in lock-in practices. Due to these concerns, some critics believe there could be a popular challenger in 2023. Let’s explore.

FreeRTOS vs ThreadX

Each of the operating systems backed by Amazon and Microsoft count unique features for developers. FreeRTOS, for example, is an RTOS kernel for embedded devices that boasts small memory size, low overhead and fast execution.

On the other hand, Microsoft’s ThreadX (also known as Azure RTOS ThreadX) carries benefits including priority-based and preemptive scheduling, fast interrupt response, interthread communication and thread synchronization.

It’s crucial to note that some developers aren’t comfortable with the corporate takeovers of FreeRTOS and ThreadX. While both corporations maintain that the respective operating system licenses are open source, Microsoft and Amazon still control the project directions. In this context, some developers are opting to forgo the two operating systems and preference independence.

The Rise of Zephyr

Enter: Zephyr. Zephyr is a scalable real-time operating system growing in microcontroller and embedded environments. It supports multiple hardware architectures and is optimized for resource-constrained devices. 

Major sponsors and contributors of the open-source collaborative effort include Intel, Nordic Semiconductor, NXP, SiFive, Synopsys and TI. Such members help shape the direction of the project and provide guidance so that all members of the community get the most out of Zephyr.

Zephyr vs FreeRTOS

Importantly, Zephyr is managed by the Linux Foundation. The non-profit organization is well-regarded for creating sustainable ecosystems around open-source projects, thereby accelerating technology development and commercial application. Of course, Linux already counts scores of operating system fans that will likely generate additional traction for its RTOS.

Look at Nordic Semiconductor for how this independence affords improved collaboration and performance. The semiconductor company leveraged Zephyr for its new software development fit for integrated circuits. As a result, Nordic now has a single SDK that is entirely developed in the open on GitHub, with Nordic employees contributing to the codebase exactly in the same way as any other person with a GitHub account. This democratizes access to the source code as well as introducing changes to it, which offers long-term benefits to the quality of the firmware and its reliability.

For those seeking true independence in real-time operating systems, Zephyr is tough to look past.

What’s Next For RTOS

Zephyr has grown impressively since inception in 2016, providing developers with a strong and stable foundation for immediate project start. Going forward, one can predict even further movement in this direction. The comparatively hard controls of FreeRTOS and ThreadX by Amazon and Microsoft versus the open source nature of Linux is only accelerating adoption.

It must be said that, with regard to industrial IoT, Microsoft is still well-placed. The company is already deeply integrated into IT departments and counts a large partner ecosystem. Last month, Gartner published the Magic Quadrant for Global Industrial IoT Platforms report. Out of the 16 companies considered for the analysis, Microsoft secured a slot in the top right quadrant as a leader in the IIoT platform segment.

Nonetheless, Zephyr is growing precisely because some don’t want to choose between one of the big players. Microcontroller manufacturers, for example, may not want to make this decision on behalf of their customers. Therefore, they want neutral governance and neutral ground. In this sense, Zephyr is perfect for those who want to keep clear of the likes of Microsoft and Amazon and ensure fully open source operations. Watch this space in 2023 and beyond.

FAQs about FreeRTOS vs ThreadX vs Zephyr

Why is Zephyr better than FreeRTOS?

Zephyr is often considered better than FreeRTOS for certain applications due to its broader hardware support, robust networking capabilities, and seamless integration with other Zephyr-based products and services.

What is the difference between FreeRTOS and Zephyr?

The main differences between FreeRTOS and Zephyr lie in their design philosophies, supported architectures, licensing, and ecosystem. Zephyr offers broader hardware support and extensive connectivity options, while FreeRTOS is well-known for its simplicity and stability.

What is the difference between FreeRTOS and RT-Thread?

FreeRTOS and RT-Thread are both real-time operating systems, but they have differences in architecture, supported platforms, licensing, and community support. RT-Thread is known for its microkernel design and rich components, while FreeRTOS is recognized for its simplicity and stability.

Why is FreeRTOS so popular?

FreeRTOS is popular due to its simplicity, robustness, and widespread support across a wide range of microcontrollers and architectures. It also benefits from a large and active community, extensive documentation, and a permissive open-source license.

About The Author

CEO and Founder, Nabto

Carsten Rhod Gregersen is the CEO and founder of Nabto, a peer-to-peer (P2P) based platform to IoT devices. Carsten counts almost two decades of experience leading software and innovation ...