Ignis OS

What is Ignis?

Ignis is an open source hobby OS meant to gain experience with low level concepts and implementations. This is a learning project, and I hope to expand it to learn more about all of the concepts. I am using a variety of tools to facilitate my learning, including CPU documentation, hardware docs, and some genAI tools to help me learn.
This is NOT a Linux distribution or UNIX system. It is currently just a kernel(userspace in the future), built from nothing.

Technical Description

• It is designed for 64-bit systems for the x86 instruction set
• It uses a custom Multiboot2 compatible boot header with GRUB2
• For testing and developing, it is emulated using QEMU
• For a full feature list, look here

Installation

Expected Environment

A Unix-like host OS is expected for building and running IGNIS OS. Linux with a mainstream distribution is recommended but macOS will likely work as well, though it has not been tested. Windows is only supported via WSL2.

Required Build Dependencies

• A modern C compiler(GNU gcc recommended)
• A linker (GNU ld recommended)
• An assembler (nasm recommended)
• grub-mkrescue
• make

Required Emulator

• You must install the QEMU emulator to for this project.
• It is expected by make run to emulate the ignis.iso image created by make

Getting Started

Steps:

• Install build dependencies.
• Clone the repo with git clone https://github.com/jkelley129/IGNIS-OS.git && cd IGNIS-OS
• Compile and package the project with make or make all
  • The Makefile creates a ignis.iso file in iso/boot/ that is emulated by QEMU
• If running with a disk image, run make disks, make disk-ata, or make disk-nvme. Note that only ATA is working at the moment
• Run the QEMU emulator with make run if not working with disks, else use make run-full, make run-ata, or make run-nvme for your disk

Current Features

Features in rough chronological order of implementation

• Console layer for outputting text to the screen via VGA
• Interrupt Descriptor Table for handling interrupts(keypresses, hardware interrupts)
• Interactive kernel-level shell for debugging and functionality
• Programmable Interval Timer with interrupt handling
• Custom memory allocator, with a simple free list implementation
• In-memory filesystem with simple utilities(create, list, copy, delete, etc.)
• Agnostic block device I/O layer
• Block device drivers
  • ATA
• Error handling with enums(kerr_t) and helper functions/macros
• Generic driver registration system with features like priority and dependencies
• Serial driver for external logging
• Page-aligned memory allocator
• Kernel Panic
• Sophisticated memory allocators
  • Buddy allocator
  • Slab allocator
  • Unified allocator interface(mm/allocators/kmalloc.c)
• Process scheduler and task system with support for multiple processes

TODO / Project Goals

• User space with limited permissions
• Support for executing user programs
• User applications(text editor, clock, stopwatch, utilities)
• More device drivers for more devices
• Implementation of an on-disk filesystem
• Audio integration
• Graphical User Interface

Contributing

Issues

View .github/ISSUE_TEMPLATES/ for detailed issue templates. Issues are always welcome, as long as they fit the template, are reproducable, and fit the scale and theme of the project

Pull Requests

Because of the nature of this repository, I would ask anyone to refrain from large PRs implementing a lot of new logic. I want to make IGNIS as best as possible, but I want to learn and implement the core features by myself. If you have code you want to contribute, feel free to make an issue or PR. Just know that I might not merge it if I don't fully understand it. Thank you for your interest!