Reenix: Implementing a Unix-Like Operating System in Rust Alex Light (alexander
[email protected]) Advisor: Tom Doeppner Reader: Shriram Krishnamurthi Brown University, Department of Computer Science April 2015 Abstract This paper describes the experience, problems and successes found in implementing a unix-like operating system kernel in rust. Using the basic design and much of the lowest-level support code from the Weenix operating system written for CS167/9 I was able to create a basic kernel supporting multiple kernel processes scheduled cooperatively, drivers for the basic devices and the beginnings of a virtual file system. I made note of where the rust programming language, and its safety and type systems, helped and hindered my work and made some, tentative, performance comparisons between the rust and C implementations of this kernel. I also include a short introduction to the rust programming language and the weenix project. Contents 1 Introduction 1 Introduction 1 Ever since it was first created in 1971 the UNIX operat- 1.1 The Weenix OS . .2 ing system has been a fixture of software engineering. 1.2 The Rust language . .2 One of its largest contributions to the world of OS engineering, and software engineering in general, was 2 Reenix 7 the C programming language created to write it. In 2.1 Organization . .7 the 4 decades that have passed since being released, C 2.2 Booting . .8 has changed relatively little but the state-of-the-art in 2.3 Memory & Initialization . .8 programming language design and checking, has ad- 2.4 Processes . .9 vanced tremendously.