Helios OS

A tiny 32-bit x86 operating system built from scratch for educational purposes.

This is a minimal, educational operating system built from scratch for the x86 (i386) architecture. It features a custom bootloader, a 32-bit protected-mode kernel written in C and assembly, basic drivers, and a simple interrupt subsystem and basic shell.

This project is not intended for production use.And not yet tested on real hardware.

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Features

• Bootloader: Loads the kernel from disk and transitions control to 32-bit mode.
• Protected Mode: GDT setup and mode switch, with a flat memory model.
• Interrupts: IDT setup and basic ISR/IRQ plumbing.
• Screen Output: Text-mode screen driver for logging and printing.
• Timer and Keyboard Interrupt Handling: Basic interrupt handling for timer and keyboard.
• Ports I/O: Minimal port helpers for device interaction.
• Filesystem: Simple filesystem and disk driver.
• Shell: Basic shell and command interface.
• Build System: A Makefile using nasm, clang/i386-elf-gcc, and ld.lld.

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Getting Started

Prerequisites

You will need an x86 cross-compiling toolchain and QEMU. You can use either clang or i386-elf-gcc.

• Required tools: nasm, clang or i386-elf-gcc, ld.lld (with clang), qemu-system-i386, gdb

Build and Run

• Build the kernel and bootable image:

  make

• Run in QEMU:

  make run

  This launches qemu-system-i386 with the generated os-image.bin.

• Clean build artifacts:

  make clean

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Roadmap

• Paging and virtual memory
• A simple memory allocator
• An advanced disk driver
• Support for network protocols and devices
• Basic graphical capabilities

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References

• OSDev Wiki — OSDev.org