Atlas Bootloader

Atlas is a modern, hobbyist-friendly x86 bootloader. It supports FAT32 filesystems, structured configuration for multiple boot entries, and an interactive VGA menu.

Features

• FAT32 Support: Boots directly from a FAT32 partition.
• Interactive Menu: User-friendly VGA menu for selecting boot options.
• Structured Configuration: Define entries, kernels, and menu titles in config/atlas.cfg.
• Multistage Design:
  • Stage 1 (VBR): Initializes disk and BIOS, loads Stage 2.
  • Stage 2: Searches for kernel/config and transitions to Protected Mode.
  • Kernel: Minimalist 32-bit kernel with heap, VGA, and keyboard drivers.

Project Structure

• src/boot/: NASM assembly for Stage 1 & 2.
• src/kernel/: C sources for the kernel components.
• include/: Kernel header files.
• config/: Bootloader configuration (atlas.cfg).
• scripts/: Python utility for disk image creation.

Building Atlas

Requirements

• CMake (v3.15+)
• NASM (for bootloader)
• Python 3 (for disk imaging)
• QEMU (optional, for running)
• x86_64-elf-gcc (Toolchain automatically downloaded by CMake)

Steps

1. Configure:

   cmake -B build

2. Build:

   cmake --build build

3. Run in QEMU:

   cmake --build build --target run

Flashing to a USB Drive

You can write the generated disk.img to a physical USB drive using the included utility.

Caution

This will erase all data on the target drive. Double-check your selection!

Windows (Run as Administrator)

python scripts/burn_usb.py

Linux (Requires sudo)

sudo python3 scripts/burn_usb.py

The script will list available drives and ask for your confirmation before writing.

Configuration

Modify config/atlas.cfg to add or remove boot entries:

[menu]
title=My Hobby OS

[entry]
name=Standard Boot
kernel=/BOOT/KERNEL.BIN

[entry]
name=Recovery Mode
kernel=/BOOT/RECOVERY.BIN

When building, the scripts/create_disk.py tool generates a 64MB FAT32 image containing your Stage 1, Stage 2, and the configuration file.

Images

Below are some images showcasing the Atlas Bootloader: