alt Hacker NewsEmbedded Rust or C Firmware? Lessons from an Industrial Microcontroller Use Case
Comments
We passed on Rust for Ada/SPARK2014 to write to bare metal on Cortex-M processor for real-time, high-integrity, and verifiable mission-critical software. Rust is making strides to be a future competitor, but it's new to the formal verification tooling and lacks any real world legacy in our domain. Ada's latest spec. is 2022. Other than AdaCore's verified Rust compiler, Rust still does not have a stable language specification like C/C++, Lisp, or Ada, SPARK 2014. I have no doubt that it will start rising to tick all the boxes that Ada/SPARK do right now with their decades of legacy in high-intetrity, mission-critical applications. The mandate to use memory-safe software put into effect this past Jan 1 2026 puts some wind in Rust's sails, but it's more than memory-safety in this domain. Plus, I do not enjoy Rust, but Cargo is nice. We're looking at Lean for further assistance in verifying our work. I think there was and is lot of Rust evangelism that will also carry it forward and boost even more Rust popularity,
> It is concluded that Rust is a sound choice today for firmware development in this domain.
This conclusion was reached with a single experiment.
> Two teams concurrently developing the same functionality — one in C, one in Rust — are analyzed over a period of several months.
> Furthermore, Ariel OS is shown to provide an efficient and portable system runtime in Rust whose footprint is smaller than that of the state-of-the-art bare-metal C stack traditionally used in this context.
> The authors thank Davide Aliprandi and Davide Sergi of the STAIoTCraft team, and the wider Ariel OS team.
So one team had Ariel OS developer support, and it's unclear what support the other team had. Seems fair.
In Figure 12, they simply stop optimizing the code once desired rate is reached. Just at the end of the project the Rust firmware gets over a third performance boost, most likely from their OS developers.
Additionally, there is a claim that "Ariel OS is shown to provide an efficient and portable system runtime" - but there are no real tests for portability are conducted. Worst still:
> Where C-based projects require a separate project setup and manual code copying per target, Rust on Ariel OS consolidates everything within a single project [..]
This claim is just not true. This sounds like somebody that is not as familiar with C.
I'm a big fan of Rust on embedded (and think embassy in particular is awesome, haven't tried this Ariel OS.)
I would say however that there's still toolchain issues here. There all kinds of MCUs that simply don't/won't have a viable compiler toolchain that would support Rust.
e.g. I recently came from a job where they built their own camera board around an older platform because it offered a compelling bundle of features (USB peripheral support and MIPI interface mainly). We were stuck with C/C++ as the toolchain there, as there was no reasonable way to make this work with Rust as it was a much older ARM ISA
off topic question: why is there no source attached to this paper?
Authors are from STMicro, polytechnic Turin, Freie universitat Berlin, and Inria. Examined writing firmware for an IOT sensor platform. From the abstract:
> Two teams concurrently developing the same functionality (one in C, one in Rust) are analyzed over a period of several months. A comparative analysis of their approaches, results, and iterative efforts is provided. The analysis and measurements on hardware indicate no strong reason to prefer C over Rust for microcontroller firmware on the basis of memory footprint or execution speed. Furthermore, Ariel OS is shown to provide an efficient and portable system runtime in Rust whose footprint is smaller than that of the state-of-the-art bare-metal C stack traditionally used in this context. It is concluded that Rust is a sound choice today for firmware development in this domain.