my loneliness is killing me

A hobby x86 operating system born from loneliness, written from scratch in assembly and C with a working shell, text editor, virtual filesystem, ROM filesystem, and a playable Snake game.

Features

• Real Mode to Protected Mode switching
• Global Descriptor Table (GDT) implementation
• A20 line enable
• Kernel loaded from disk
• C kernel with assembly entry point
• Physical Memory Manager (PMM)
• PIT-based timer driver
• Interactive Shell with piping (|) and redirection (>, >>, <)
• Virtual Filesystem (VFS) with inode/dentry tree
• RAM Filesystem (flat structure)
• ROM Filesystem (built-in read-only files: help.txt, version.txt, motd.txt)
• Gap-buffer text editor (edit)
• VGA Mode 13h graphics driver (320×200, 256 colors)
• Playable Snake game (snake)
• QEMU testing support
• GDB debugging capabilities

Architecture

• Bootloader (src/arch/x86/boot.asm): Real mode initialization, disk loading, mode switching
• Kernel Assembly (src/arch/x86/kernel.asm): 32-bit entry point
• Interrupts and IDT (src/arch/x86/interrupts.asm, src/arch/x86/idt.c, src/arch/x86/idt.h): Exception and interrupt setup
• Drivers (src/drivers/): VGA text mode, VGA mode 13h, keyboard, and timer
• Kernel C (src/kernel/kernel.c): Main kernel logic
• Memory (src/memory/pmm.c, src/memory/pmm.h): Physical memory management (256MB)
• ROM Filesystem (src/fs/romfs/): Built-in read-only files (help.txt, version.txt, motd.txt)
• Shell (src/shell/): Interactive shell and command history
• Filesystem (src/fs/): Flat RAM FS and VFS layer
• Editor (src/editor/): Gap-buffer text editor
• Games (src/games/): Snake
• Linker Script (linkerscript.ld): Memory layout

Installation

GCC and Binutils

The bootloader requires GCC (GNU Compiler Collection) and binutils to compile and link the kernel and bootloader code.

GCC compiles C code to machine code, while binutils provides essential tools like:

• as (assembler) - assembles .asm files to object files
• ld (linker) - links object files into the final kernel binary
• objdump, objcopy, readelf - utilities for examining and manipulating binary files

Debian/Ubuntu

sudo apt install gcc binutils nasm

Arch Linux

sudo pacman -S gcc binutils nasm

Fedora

sudo dnf install gcc binutils nasm

macOS (Homebrew)

brew install gcc binutils nasm

Verify installation:

gcc --version
ld --version
as --version

Quick Start

After installing dependencies (see Installation section):

# Build OS image using native GCC (with -m32)
make clean
make

Testing

# Run with QEMU
qemu-system-x86_64 -drive format=raw,file=./bin/os.bin,if=ide,index=0

# Debug with GDB
qemu-system-x86_64 -drive format=raw,file=./bin/os.bin,if=ide,index=0 -s -S &
gdb ./bin/kernel.bin
(gdb) target remote localhost:1234
(gdb) break shoot_on_your_own_foot
(gdb) continue

Requirements

• NASM assembler
• GCC (with support for -m32)
• GNU Make
• QEMU (for testing)
• GDB (for debugging)

Time Spent

• ~76hours

License

MIT