Rust and WebAssembly represent an exciting combination of technologies for building highly performant and secure operating systems. In this article, I will explore how Rust and WebAssembly enable operating system developers to build the OS of the future.
Why Build a New OS?
Operating systems like Windows, macOS, and Linux have dominated personal computing for decades. However, these operating systems were designed in a different era and have accrued layers of legacy code over time.
There are several reasons why we may want to build a new OS from the ground up:
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Performance – Removing legacy code and designing for modern hardware can result in significant performance improvements. WebAssembly specifically is well-suited for near-native performance.
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Security – Legacy code in existing OSes creates a large attack surface vulnerable to exploits. A new OS can be designed with security as a first-class concern.
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Flexibility – An OS designed around WebAssembly can adapt to new hardware and use cases more easily than traditional OSes.
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User Experience – A new OS enables rethinking the user experience to create more intuitive and seamless interactions.
Why Rust and WebAssembly?
Rust is a modern systems programming language designed for performance, reliability, and productivity. Key features include:
- Memory safety without garbage collection
- Rich type system and ownership model to prevent bugs
- Excellent performance on par with C and C++
- Concurrency support via message passing
WebAssembly is a portable bytecode instruction format optimized for fast startup and execution. It provides several benefits:
- Near-native performance across platforms
- Safe execution environment isolated from host machine
- Compact file sizes for efficient delivery
- Designed to integrate well with JavaScript, HTML, and other web technologies
Together, Rust and WebAssembly are an ideal combination for building secure and performant system components. Rust’s focus on safety makes the WebAssembly code robust, while WebAssembly provides portable high-performance execution.
Designing the OS Architecture
The architecture of the new OS needs to be designed with Rust and WebAssembly in mind. Here are some key considerations:
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Modularity – The OS should be built out of small, isolated components that communicate via well-defined interfaces. This aligns well with Rust’s principles.
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Asynchronicity – WebAssembly currently only supports synchronous calls. The OS needs asynchronous APIs to prevent blocking.
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Sandboxing – OS processes should run in sandboxes enforced by WebAssembly for security. Inter-process communication can use WebAssembly SIMD and Atomics.
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Web Integration – APIs for seamless integration with web technologies like the DOM, CSS, WASI, and WebGPU.
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Deployment – The OS will be distributed as WebAssembly modules that can be fetched and instantiated on demand.
An effective architecture will leverage Rust’s advantages for systems programming while working within WebAssembly’s constraints.
Building Core OS Services
With the architecture defined, we can start building out core OS services:
File System
- A file abstraction providing a consistent interface across physical and virtual file systems. Should support asynchronous reads and writes.
- Virtual file systems like tmpfs and procfs to access non-persistent resources.
- Sandboxed access to physical drives to prevent uncontrolled I/O.
Network Stack
- A user space TCP/IP stack for high performance networking.
- APIs for asynchronous sockets using WebSockets and WebTransport.
- Secure communication between sandboxed processes.
Graphics and UI
- WebGPU integration for hardware accelerated 3D graphics.
- Ability to render HTML and CSS for applications.
- Windowing system for managing documents and applications.
Package Management
- A package manager for installing and updating applications and libraries as WebAssembly packages.
- Cryptographic verification of packages from trusted sources.
- Sandboxed installation to isolate applications.
These core services demonstrate how to build OS functionality with Rust and WebAssembly while adhering to the architecture principles.
Putting it All Together
With modular OS services implemented in Rust and WebAssembly, we can begin assembling them into a coherent OS:
- A bootloader initializes the core OS components.
- The init process configures the system state and launches essential services.
- A display server presents a login prompt using HTML/CSS.
- An authentication manager verifies user identity and establishes a session.
- A window manager displays and manages applications per user session.
- Applications can be written in any language compiled to WebAssembly.
- A package manager enables installing new applications from a trusted repository.
The result is a highly performant and secure OS powered by Rust and WebAssembly, providing an innovative user experience. While significant work remains, we now have a blueprint for building the OS of the future.
Conclusion
Rust’s memory safety and WebAssembly’s portable performance make them an ideal combination for systems programming. By designing a modular, asynchronous, and web-integrated architecture, we can build an OS offering compelling advantages over legacy systems. There are still challenges to tackle, but Rust and WebAssembly provide the building blocks for the next generation of operating systems. With continued collaboration from the open source community, the OS of the future could soon become a reality.
