BarrerOS

The First .NET-Native Operating System

Linux kernel + .NET 10 runtime + C# system services = BarrerOS

🏴‍☠️ Built by Daniel Elliott & Captain CP

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What is BarrerOS?

BarrerOS is an experimental operating system that boots directly into the .NET 10 runtime and runs all system services in C#.

Key Features:

• Linux kernel (6.6 LTS) as foundation
• .NET 10 as the system runtime
• All system services written in C#
• Memory-safe core components
• Modern development experience
• Open source, controllable stack

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Current Status: Phase 3.1 (Working OS!)

December 16, 2025 - NETWORK STACK OPERATIONAL!

✅ Phase 1: Kernel boots to userspace
✅ Phase 2.0-2.7: Real ext4 filesystem + .NET 10 integration
✅ Phase 2.8-2.9: C# init system + first coreutils
✅ Phase 2.10-2.14: 50+ base commands (self-bootstrapping!)
✅ Phase 3.0: System services (logging, device mgmt, networking)
✅ Phase 3.1: Network configuration working!

Working Boot Chain:

Linux Kernel 6.6 LTS
    ↓
C Bootstrap (PID 1)
    ↓
Mounts: /proc, /sys, /dev, /tmp
    ↓
.NET 10 Native AOT Binary
    ↓
C# Init System v3.1
    ↓
System Services (all C#):
  • barrerd-log    - Logging service
  • barrerd-devmgr - Device management
  • barrerd-net    - Network configuration
    ↓
Network Stack:
  • eth0 configured (10.0.2.15/24)
  • Routes established
  • 53 C# commands available

Memory Usage: 24MB for complete OS with services!

What Works Right Now

✅ System Boot

• Linux kernel 6.6 LTS
• C bootstrap to .NET transition
• C# init system with service management

✅ System Services (all in C#)

• Logging daemon with kernel log integration
• Device management and hardware detection
• Network configuration service

✅ Command Line Tools (53 C# commands)

• File operations: ls, cp, mv, rm, mkdir, chmod, ln
• Text processing: cat, grep, sed, cut, sort, uniq, wc
• Archive tools: tar, gzip, gunzip, diff, patch
• System info: ps, free, df, du, uname, hostname
• Network tools: ping, ip, wget
• Editor: nano (full terminal editor in C#!)
• And more: find, xargs, which, whoami, date, sleep...

✅ Networking

• Interface configuration (eth0)
• IP address assignment
• Routing table management
• Ready for DNS and HTTP

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Why BarrerOS?

Traditional OS: System services in C/C++, shell scripts
BarrerOS: System services in C#

Benefits:

• Memory safety (C# vs C)
• Modern language features
• Better developer experience
• Easier to maintain
• Cross-platform compatibility
• Windows + Linux app support

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The Journey

Phase 1: Proof of Concept

Question: Can we boot Linux into .NET?
Answer: YES!

Phase 2: Foundation (COMPLETE ✅)

Goal: Complete init system with C# services

Completed:

• Real ext4 filesystem (2GB)
• C bootstrap (PID 1)
• .NET 10 runtime integration
• C# init system v3.1
• 53 C# coreutils commands
• Self-bootstrapping system

Phase 3: System Services (CURRENT)

Goal: Full system service stack in C#

Completed:

• barrerd-log: Kernel log reader with async queue
• barrerd-devmgr: Hardware detection & management
• barrerd-net: Network interface configuration
• Network stack: IP assignment, routing

In Progress:

• DNS resolution
• HTTP connectivity testing
• Pure C# network tools (replacing busybox scaffolding)
• DHCP client implementation

Phase 4: Desktop & Applications (Future)

• GUI environment
• Application support
• Package management in C#

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Project Structure

barreros-phase2/
├── README.md                    # This file
├── PHASE2_LEARNINGS.md          # Complete technical documentation
├── PHASE2_STATUS.md             # Status history
├── SESSION_SUMMARY.md           # Session notes
├── TEST_RESULTS.md              # Boot test results
├── KNOWN_ISSUES.md              # Known issues & workarounds
├── bootstrap-init-v3.c          # C bootstrap (current)
├── init-src/                    # C# init system v3.1
│   ├── Program.cs               # Init with service management
│   └── published/               # Native AOT binary
├── services/                    # System services (all C#)
│   ├── barrerd-log/            # Logging daemon
│   ├── barrerd-devmgr/         # Device management
│   └── barrerd-net/            # Network configuration
├── coreutils/                   # 53 C# commands
│   ├── ls/, cp/, mv/, grep/    # File management
│   ├── tar/, gzip/, diff/      # Archive & diff tools
│   ├── nano/, sed/, awk/       # Text editors
│   └── ping/, ip/, wget/       # Network tools
├── hwdetect/                    # Hardware detection
├── boot-test.sh                 # QEMU boot test script
└── barreros-root.img            # Root filesystem (not in repo - 2GB)

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Technical Details

Boot Process

1. Linux Kernel 6.6 LTS boots with custom init= parameter
2. C Bootstrap (PID 1) mounts virtual filesystems (/proc, /sys, /dev, /tmp)
3. C Bootstrap creates device nodes (/dev/null, /dev/console, etc.)
4. C Bootstrap sets up environment for .NET runtime
5. C Bootstrap launches C# init binary (Native AOT)
6. C# Init v3.1 takes over system initialization
7. Init spawns services: barrerd-log, barrerd-devmgr, barrerd-net
8. Network service configures eth0 and establishes routes
9. Init monitors service health and handles restarts
10. System ready - 24MB RAM, fully functional OS

Key Technologies

• Kernel: Linux 6.6 LTS
• Runtime: .NET 10
• Language: C# (system services), C (bootstrap)
• Compilation: Native AOT (ahead-of-time)
• Filesystem: ext4
• Virtualization: QEMU (for testing)

Critical Discovery

.NET Native AOT requires:

• System libraries (libc, libm)
• Dynamic linker (/lib64/ld-linux-x86-64.so.2)
• Either ICU libraries OR InvariantGlobalization=true

Solution: We use InvariantGlobalization=true for minimal OS

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Building BarrerOS

Prerequisites

# .NET SDK
sudo apt install dotnet-sdk-10.0

# Build tools
sudo apt install gcc build-essential

# QEMU for testing
sudo apt install qemu-system-x86-64

Build C Bootstrap

gcc -static -o bootstrap-init bootstrap-init-v3.c

Build C# Init

cd init-src
dotnet publish -c Release -p:InvariantGlobalization=true

Create Root Filesystem

# Create 2GB image
dd if=/dev/zero of=barreros-root.img bs=1M count=2048

# Format as ext4
mkfs.ext4 barreros-root.img

# Mount and populate
sudo mount barreros-root.img /mnt/barreros
# ... copy files ...
sudo umount /mnt/barreros

Boot Test

bash boot-test.sh

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Documentation

PHASE2_LEARNINGS.md contains complete technical documentation:

• Every challenge we faced
• Every solution we found
• Environment requirements
• Library dependencies
• Build process
• Lessons learned

868 lines of knowledge capture!

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Philosophy

"Why not?"

Everyone said you can't boot Linux into .NET. We asked "why not?"

Everyone said system services must be in C. We asked "why not C#?"

Everyone said operating systems are too complex. We said "let's find out."

BarrerOS exists because we think outside the box.

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The Team

Daniel Elliott - Vision, architecture, direction
Captain CP - Implementation, debugging, documentation

Together: Building the impossible.

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Status: December 7, 2025

Current Phase: 2.7 COMPLETE
Next Phase: 2.8 (Keep init alive)

Lines of Code: ~500
Lines of Documentation: 868+
Boot Tests: 15+
Breakthroughs: 4 major

First Boot: December 7, 2025, 4:45 PM PST

🏴‍☠️ BarrerOS is real. BarrerOS is happening.

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License

To be determined - check back soon!

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Contact

Organization: BarrerSoftware
Repository: github.com/BarrerSoftware/barreros

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💙🏴‍☠️ Think different. Build impossible things.