Strix OS

A bare-metal x86-64 operating system kernel written in Rust, designed for eventual Linux application compatibility.

Overview

Strix OS is a hobby operating system project that starts from first principles: no standard library, no operating system, just raw hardware. The long-term goal is to run Linux applications (ELF binaries with syscall compatibility), making it a practical learning platform for OS development.

Current Status: Phase 0-1 (Foundational Infrastructure)

The kernel boots, handles interrupts, displays text, and manages memory at a basic level:

Not yet implemented: Heap allocation, user space, syscalls, file systems, process management.

Building

Prerequisites

• Rust nightly toolchain (specified in rust-toolchain)
• QEMU for running and testing

Commands

All commands run from the StrixKernel/ directory:

# Build the kernel
cargo build

# Build and run in QEMU
cargo run

# Run all tests
cargo test

# Run a specific integration test
cargo test --test basic_boot
cargo test --test stack_overflow
cargo test --test should_panic

Project Structure

.
├── CLAUDE.md              # AI assistant instructions
├── roadmap.md             # Development roadmap (6 phases)
├── README.md              # This file
└── StrixKernel/
    ├── Cargo.toml         # Dependencies and build config
    ├── x86_64-strix_os.json  # Custom target specification
    ├── src/
    │   ├── main.rs        # Kernel entry point, panic handlers
    │   ├── lib.rs         # Core library, test framework
    │   ├── gdt.rs         # Global Descriptor Table + TSS
    │   ├── interrupts.rs  # IDT, exception/IRQ handlers
    │   ├── memory.rs      # Page tables, frame allocation
    │   ├── vga_buffer.rs  # VGA text mode output
    │   └── serial.rs      # Serial port debugging
    └── tests/
        ├── basic_boot.rs     # Smoke test for boot process
        ├── stack_overflow.rs # IST stack switching test
        └── should_panic.rs   # Panic handler test

Architecture

Boot Process

1. Bootloader (bootloader crate v0.9) loads kernel ELF and sets up paging
2. Entry point (kernel_main in main.rs) receives BootInfo
3. Initialization (strix_os::init()) sets up GDT → IDT → PICs
4. Halt loop waits for interrupts

Memory Model

The bootloader maps all physical memory at a fixed virtual offset (0x0000256000000000). This enables:

• OffsetPageTable: Simple virtual ↔ physical translation
• BootInfoFrameAllocator: Allocates frames from the bootloader's memory map

Interrupt Handling

The 8259 PIC remaps IRQs 0-15 to vectors 32-47 to avoid conflicts with CPU exceptions.

Test Framework

Tests run as separate kernel instances in QEMU:

• Output goes to serial port (-serial stdio)
• Exit codes via ISA debug device (port 0xf4)
• Success = 0x10 (QEMU exit 33), Failure = 0x11 (QEMU exit 35)

Roadmap

See roadmap.md for the full 6-phase development plan:

1. Memory Management - Heap allocator, advanced paging
2. User Space Foundation - Ring 3, syscalls, processes
3. ELF Loading - execve(), static binaries
4. Virtual File System - VFS layer, ramfs, devfs
5. POSIX Essentials - Signals, pipes, process groups
6. Init System - TTY, mount, OpenRC support

Key Dependencies

Resources

• Writing an OS in Rust - Primary learning resource
• OSDev Wiki - x86 hardware documentation
• Intel SDM - Official CPU manuals
• Linux Syscall Table - Syscall reference

License

This project is for educational purposes.