Tsukasa
A handmade desktop operating system built from scratch.
32-bit bare-metal desktop operating system built entirely in C and Assembly
What is Tsukasa?
Tsukasa is a modern, 32-bit bare-metal desktop operating system — built entirely in C and Assembly, without relying on any standard library or existing OS infrastructure.
Every layer of the system from the bootloader to the graphical desktop has been single developed. Tsukasa boots directly onto the hardware, initializes its own framebuffer, and launches a full window manager with a translucent glass aesthetic, all without a runtime underneath it.
The virtual filesystem mounts a FAT12 ramdisk for read access and a MemFS layer for in-session writes. A suite of built-in desktop applications, Settings, File Manager, Notepad, Calculator, and Terminal, complete the environment.
The project is still in early development. Major components are being actively implemented.
What it can do
Built from scratch, here is what Tsukasa can do.
Window Manager
True Z-ordering, focus management, drag-and-drop, and window closing. Sleek, semi-transparent dark glass UI with drop shadows, rounded corners, and macOS-style traffic light buttons. Global accent colors configurable at runtime.
Desktop Shell
A functional desktop environment with an active taskbar showing window pills, a start menu, and clickable desktop shortcut icons — all rendered directly to the framebuffer.
Virtual File System
A dual-layer VFS mounts a FAT12 ramdisk loaded via GRUB at / for read access, and a MemFS in-memory layer at /tmp/ for temporary writable session storage.
Built-in Applications
Five desktop applications shipped with the OS: Settings for accent and wallpaper control, File Manager with icon grid browsing, Notepad with FAT12 read and /tmp/ save, Calculator, and Terminal.
Wallpaper Engine
Parses 24-bit and 32-bit uncompressed BMP bitmap files natively. Uses nearest-neighbor scaling to fit any resolution directly into the framebuffer VRAM — no external library.
Low-level Architecture
Boots at the 1 MiB mark with paging enabled, identity-mapping 16 MiB of RAM. Event-driven window redraws via a global event queue routing IRQ12 mouse and keyboard packets.
Built from scratch.
No standard library. No OS layer underneath. Every subsystem,from the bootloader to the window compositor,is written directly against the hardware. This is bare-metal systems programming in the most literal sense.
$ gcc -m32 -ffreestanding -nostdlib -nostdinc kernel.c -o tsukasa.bin
No operating system. No runtime. Just the hardware, your code, and intent.
Where it stands
Tsukasa is early in development. The foundations are real, the desktop identity is established, the work is ongoing.
This is a living project. The list above reflects the reality at time of writing.
Official Sticker Pack
A collectible set of stickers, no printing yet. .
// printing coming soon
Keep Tsukasa growing
Tsukasa is a passion project built in spare time, any support means a great deal and helps keep the late nights going.
Every contribution goes directly toward more development time, design experiments, and future features.
// additional methods coming soon