🔷 ZironOS — A Tiny 32-bit Kernel in Zig

ZironOS is a minimalistic multiboot-compliant kernel written in Zig and x86 assembly. It boots with a boot animation using GRUB, prints to the screen using VGA text mode, and captures real-time keyboard input using raw scancodes.

https://github.com/user-attachments/assets/b72d2211-24b0-430e-97fb-9e2410b250c9

🌲 Project Structure

ZironOS/

│   ├── main.zig           # Kernel logic (VGA + Keyboard input)
│   └── boot.s             # Entry point (_start) & stack setup
├── iso_root/
│   └── boot/
│       └── grub/
│           └── grub.cfg   # GRUB bootloader config
├── build.zig              # Zig build system
├── linker.ld              # Linker script with multiboot header
├── Makefile               # Build + run automation
└── README.md              # This file

🧰 Requirements

Zig 0.11.0

GRUB Tools: grub-mkrescue, xorriso, etc.

QEMU (for testing without physical hardware)

📦 Install on Ubuntu/Debian

sudo apt update sudo apt install grub-pc-bin xorriso qemu-system-x86

📦 Install on Arch

sudo pacman -S grub xorriso qemu

🚀 Build and Run 🔁 One-Command Boot Test

make run

🧱 Full Lifecycle

make check # Ensure dependencies exist make clean # Remove old build/cache make iso # Build & generate ISO image make run # Launch QEMU and boot ZironOS

🖥️ What ZironOS Does

✅ Boots via GRUB (Multiboot 1) ✅ Sets up a clean stack and calls main ✅ Initializes a VGA buffer (80x25, 16 colors) ✅ Prints text in color using low-level memory writes ✅ Captures keyboard input and prints each character in real time

✨ Output on Boot

ZironOS v0.2.0

ZironOS>

Then you can start typing — and it responds instantly! 🧪 Testing on QEMU

Basic test

make run

With debugging

make debug

💻 Testing on Real Hardware (⚠️ Expert-Only)

sudo dd if=zironos.iso of=/dev/sdX bs=4M status=progress

Then reboot and boot from the USB. 🧠 What's Inside

boot.s sets up the multiboot header, entry point, and stack

main.zig initializes the terminal and enters a keyboard input loop

linker.ld ensures .multiboot is placed early and sections are aligned properly

grub.cfg makes GRUB load the kernel via multiboot /zironos

🧱 Future Plans

⌨️ Basic shell with built-in commands

📦 Memory paging

📁 FAT32/EXT2 read-only FS support

🧵 Task switching & cooperative multitasking

🔌 Basic driver support (timer, serial)

❓ Troubleshooting 🔻 GRUB: No Multiboot Header Found?

Ensure .multiboot is the first section in linker.ld

Check objdump -h zig-out/bin/zironos — .multiboot must be near 0x100000

🔻 "Permission denied" or PAT issues with git push?

Use a Personal Access Token instead of password

Example:

Username: your-github-username
Password: <paste your token here>

💬 Credits

Built with 💙 using:

Zig 0.11.0

x86 assembly

GRUB bootloader

QEMU for testing