I've been working as a Java programmer for several years and want to learn a lower-level language as a hobby. My main interest is exploring and modifying existing open-source operating systems such as Linux or a BSD variant, rather than building an operating system from scratch. C appeals to me because it is relatively small, historically important in systems programming, and exposes more of what is happening under the hood. Rust is also interesting because it provides stronger safety guarantees and is increasingly being used for systems tools and some operating-system components. Which language would be the better starting point, and should I prioritize Rust because it may become more important for operating-system development in the future?
5 Answers
Rust is a perfectly reasonable first choice if you prefer its safety features and stricter compiler. It prevents many of the mistakes that make C difficult, and it’s increasingly useful for new systems software. However, Rust does not replace the need to understand C when your goal is to work with existing operating-system code, so you’ll probably want to learn C eventually anyway.
Start with C. Most of the Linux and BSD code you’re likely to read is still written in C, so learning it will make the existing codebase and low-level concepts much easier to understand. C is small enough that you can learn the basics quickly, and it exposes memory, pointers, data layout, and manual resource management directly. Once you’re comfortable with that, Rust will be easier to appreciate and learn.
Learn both, probably in that order. C is valuable because of the enormous amount of systems software already written in it. Rust is valuable because its ownership model and compiler catch many memory and concurrency mistakes before the program runs. They teach different lessons: C shows you the underlying mechanics, while Rust makes you reason carefully about safety and lifetimes.
The quickest way to learn either language is to build something small. Try writing a shell, a simple memory allocator, a tiny filesystem, or a basic systems utility in C. Afterward, implement a similar project in Rust and compare the development experience. That will teach you much more than debating which language will eventually become the standard.
Don’t choose based only on which language might be popular years from now. Languages are tools, and the best one depends on the project. For Linux or BSD, choose the language used by the component you want to modify. If you’re studying an existing kernel subsystem, that will usually mean C; if you’re building a new user-space utility or Rust component, Rust may be the better fit.
Rust adoption is growing, but that doesn’t mean the large existing C codebases will disappear anytime soon. Learning C first gives you access to far more of the operating-system code you want to explore.