Rust Multi-Microkernel OS • Capability Security • BSD Licensed • Winter Saga Release
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Welcome to GuardBSD Documentation
This is the official documentation for GuardBSD - a secure, capability-based, multi-microkernel operating system written entirely in Rust.
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Use the sidebar to navigate through architecture, installation, APIs, internals and user guides.
Overview
GuardBSD is a modern, secure operating system built on a unique three-microkernel architecture, unlike traditional monolithic or single-microkernel designs:
- µK-Space - memory management
- µK-Time - scheduling & timers
- µK-IPC - inter-process communication
Each microkernel is:
- minimal,
- isolated,
- formally verifiable,
- responsible for one strictly defined subsystem.
GuardBSD is designed for high-assurance environments, formal verification,
and multi-architecture support (x86_64 and ARM64).
Design Philosophy
Separation of Concerns
Each microkernel implements exactly one subsystem - eliminating kernel bloat and reducing bugs.
Security First
- Capability-based security model
- No ambient authority
- Full revocation & delegation
- Minimal trusted computing base
Formal Verification
Microkernels are intentionally small enough for automated proof systems.
Multi-Architecture Support
A unified Rust codebase supports identical behavior on x86_64 and ARM64, using architecture abstraction layers.
System Architecture
GuardBSD consists of:
- Applications
- System library (
libgbsd) - Userland servers: Init, VFS, RAMFS, DevD, NetD
- Drivers: Storage, serial, block devices
- Three microkernels: µK-Space, µK-Time, µK-IPC
- Hardware Abstraction Layer
See the detailed diagrams in Architecture Overview →
Microkernels
µK-Space (Memory)
Responsible for PMM, VMM, page tables, TLB, and address space creation.
µK-Time (Scheduler)
Implements the thread scheduler, timing subsystem, and timer interrupts.
µK-IPC (Communication)
Handles message passing, IPC ports, capability routing, and IPC syscalls.
Target Use Cases
- Secure embedded devices
- High-assurance systems
- Real-time workloads
- Virtualization environments
- Networking appliances
- Research & academic OS design
Recommended Next Sections
- Architecture - high-level and full diagrams
- Features - minimalism, security, performance
- Status - roadmap and development progress