![BlankOSshowcase](https://github.com/user-attachments/assets/63aae4ae-1633-4981-875d-8e2627ccc25c)

> [!WARNING]
> This is free and unencumbered software released into the public domain. Many things might be (are) broken.
> The project is a hobbyist operating system, and it comes without any warranty whatsoever! See the license for more info. Feedback and contributions are highly appreciated.

# BlankOS

Rewritten megalithic, ring 0, lower-half, singletasking kernel for the x86 processor architecture (using 32-bit protected mode), with GRUB 2 as bootloader. Emulation was tested on QEMU using Arch Linux 6.9.7-arch1-1, and on real hardware (UEFI and BIOS).
The long-term goal of this OS is to be capable of running user programs and having its own complete kernel C library so that users can write their own C programs and expand the system!

## Usage

Download the latest BlankOS disk image from the "Releases" tab, and start it using the QEMU emulator:

```
qemu-system-i386 blankOS-i386-0.3.55.iso
```

> [!NOTE]
> Know that the latest release is not always up-to-date with the source code. To get the most up-to-date version, instead build from source as shown below.

## Building from source

```
git clone https://github.com/xamidev/blankos
make toolchain
make
make run
```

The `toolchain` target will download the appropriate cross-compiling tools, and the `run` target will make a disk image for emulation or real hardware testing. *Some operations require root access. Always audit the code yourself before running anything as root!*

## Running on real hardware

The OS is now both UEFI and BIOS compatible! Burn your image file onto a USB stick:
```
sudo dd bs=4M if=blankos.iso of=/dev/sdX status=progress oflag=sync
```

Replace `sdX` with your USB drive name (you can find it by doing `sudo fdisk -l`).
Tada! You now have a working BlankOS USB stick. Go ahead and try it out!
(*Might not work properly on monitors that aren't Full HD*)

## Documentation

Two other documents are available to help you understand the project better. One is the User's Manual, labelled [USERS.md](docs/USERS.md), and the other one is the Developer's Manual, labelled [DEVELOPERS.md](docs/DEVELOPERS.md). They are full of useful resources: you'll learn how to use the system and how to contribute to it. *(The docs might not always be up-to-date)*

### Resources

- the [OSDev.org](https://wiki.osdev.org/Expanded_Main_Page) wiki and forums
- the [Nanobyte](https://www.youtube.com/watch?v=9t-SPC7Tczc&list=PLFjM7v6KGMpiH2G-kT781ByCNC_0pKpPN) YouTube channel
- the [Daedalus Community](https://www.youtube.com/@DaedalusCommunity) YouTube channel
- a great book named *Operating Systems: From 0 to 1*, by Tu, Do Hoang
- the Intel [64 and IA-32 Architectures Software Developer Manuals](https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html)
- [Bran's Kernel Development Tutorial](http://www.osdever.net/bkerndev/index.php)
- Ralf Brown's Interrupt List
- the [little book about OS development](https://littleosbook.github.io/) by Erik Helin and Adam Renberg

### Features / Roadmap

- [X] Booting with GRUB
- [X] Common basic structures (IDT, GDT, ISRs, IRQs)
- [X] Common drivers (framebuffer, keyboard, serial, timer, RTC, ATA PIO)
- [X] Kernel-space utilities (shell, simple programs)
- [ ] Filesystem (FAT32 or VFS ramdisk)
- [ ] Changing the default VGA font
- [X] Dynamic memory allocator (get memmap from GRUB?)
- [ ] Paging/Page Frame Allocation
- [ ] TCP/IP Network stack
- [ ] Getting to Ring-3 (userspace)
- [ ] Multitasking (via round robin scheduling)
- [ ] Advanced/other drivers (video, SB16, RTC, Ethernet)
- [X] UEFI support
- [ ] ELF parsing
- [ ] System calls
- [ ] GUI
- [ ] POSIX and ANSI specification compatibility