The Horizon of Retro-Modern Computing

AurionOS A 32-bit x86 operating system built from scratch in C and x86 Assembly. Developed as a solo learning project by a 13-year-old over the course of 14 days

AurionOS is built for the tinkerers who want to see every byte move. By stripping away modern abstractions, we reveal the elegant logic of the CPU and the hardware. Every line of code serves a purpose, offering a bloat-free environment for learning and development.

1. Ensure you have QEMU and NASM installed.
2. Run the following command:

Why does this work? The Makefile compiles the assembly bootloader and the C kernel, links them at 0x10000, and packages them into a bootable image. QEMU then loads this image, starting the execution at the BIOS handoff point.

Starts in 16-bit Real Mode, enables the A20 gate, sets up the GDT, and transitions the CPU to 32-bit Protected Mode before jumping to the kernel.

Initializes the stack and the Interrupt Descriptor Table (IDT), then calls the C kmain function to begin high-level initialization.

Uses a Memory Control Block (MCB) heap manager starting at the 1MB mark, providing kmalloc and kfree for dynamic memory allocation.

Utilizes VBE (VESA BIOS Extensions) for high-resolution linear frame buffers. The window manager handles Z-order, clipping, and redrawing.

Includes a custom implementation of Ethernet, ARP, IPv4, ICMP, and UDP, alongside a DHCP client for automatic IP configuration.

Use WSL2 (Ubuntu) for the best experience:

sudo apt update
sudo apt install -y build-essential nasm gcc make binutils qemu-system-x86 genisoimage
make run

sudo apt update
sudo apt install -y build-essential nasm gcc make binutils qemu-system-x86 genisoimage
make run

sudo pacman -S base-devel nasm gcc make qemu-desktop cdrtools
make run

brew install nasm qemu cdrtools make
make run

• Build via make all
• Run with VMware or VirtualBox instead of QEMU.

AurionOS provides kernel services via INT 0x80.

AurionOS uses a custom sector-based filesystem (AurionFS) for persistent storage. It stores file metadata in reserved sectors (starting at LBA 500) and file contents in a dedicated data area (starting at LBA 700).

• In-Memory Cache: The kernel maintains an fs_table for quick access to file metadata.
• Persistence: Changes are flushed to disk using fs_save_to_disk().
• Legacy Support: A FAT12 driver (src/filesys.asm) is also available for reading external media.

The shell is the primary CLI interface, supporting over 100 commands. Commands are dispatched via a central table in src/commands.c.

• DIR: List files in the current directory.
• CAT <file>: View file contents.
• NANO <file>: Edit text files.
• NETSTART: Initialize networking and DHCP.
• GUIMODE: Switch to the graphical desktop.
• PYTHON: Launch the minimal Python interpreter.

To add a new command to the OS, you don't need a separate binary - simply register it in the kernel:

1. Implement the command in src/commands.c:

   static int cmd_demo(const char *args) {
       puts("Hello, AurionOS World!\n");
       return 0;
   }

2. Register it in the commands[] table at the end of src/commands.c:

   static const Command commands[] = {
       ...
       {"DEMO", cmd_demo},
       {NULL, NULL}
   };

3. Compile and Run: Run make run and type DEMO in the shell.

• Real hardware boot is currently unstable (working on it!)
• Best experience: QEMU, VirtualBox, or VMware
• This is a beta release - bugs are expected and being fixed

AurionOS is licensed under the MIT License.

AurionOS - Where Every Byte Matters Built with passion by Luka. March 2026.