Redox: An operating system in Rust
With the Rust-for-Linux project starting to gain some ground, it is worth looking at other operating systems that use Rust in their kernels. There are many attempts to use Rust for operating system development, but Redox may be the most complete. Redox is an MIT-licensed microkernel and corresponding user space, designed around concepts taken from Plan 9. While nowhere near being usable as a replacement for Linux, it already provides a graphical user interface and the ability to run many POSIX programs.
Redox was started in 2016 by Jeremy Soller, who remains the project's benevolent dictator for life. Soller also works as a maintainer for Pop!_OS. Since then, approximately 150 people have contributed to Redox. The project summarizes its goals as ""to make a complete, fully-functioning, general-purpose operating system with a focus on safety, freedom, stability, correctness, and pragmatism"". The project aims to eventually become a practical alternative to Linux or BSD, although it does not aim for strict binary compatibility with either.
Redox has a number of different components, mostly written in Rust. The project doesn't forbid software written in other languages; it has an implementation of the C library on top of the Redox kernel called relibc. Using the library lets software written in C run on Redox. However, the core concepts of the system are sufficiently different that the main services of the operating system — the shell, user interface, and so on — mostly have to be written from scratch.