One year of developing my own operating system

Writing an operating system from scratch is something I always wanted to do, and last year, I started working on MONOLITH, an operating system meant to make my dream true.

This operating system is meant as a fun learning experience to know more about operating systems, and to improve my programming skills in general.

1st month: GDT, IDT, Memory Management and the console#

• 29/03/2025: The first step when developing an operating system is usually getting it to boot, here I used multiboot2 protocol boot protocol.

• 30/03/2025: I initialized both the GDT and the IDT.

• 31/03/2025: Implemented some functions for logging to serial.

• 03/04/2025: Implemented a physical memory manager.

• 05/04/2025: Implemented a heap allocator.

• 11/04/2025: Added support for i386 architecture.

• 15/04/2025: Implemented a VGA console.

• 28/04/2025: Implemented a VESA video driver for i386.

2nd month#

No interesting developments happened during that month, mostly due to college distractions and lack of motivation.

3rd month#

• 02/06/2025: Switch from multiboot2 to Limine boot protocol.

• 03/06/2025: Drop i386 and Text VGA mode support.

• 08/06/2025: Add support for virtual memory management.

• 10/06/2025: Add support for PIT timer.

• 18/06/2025: Implement a VFS and a tmpfs.

4th month#

• 23/07/2025: Add support for an initrd.

• 30/07/2025: Implement an ELF loader.

5th month#

• 12/08/2025: Initial ring-3 and syscalls support.

• 18/08/2025: Ported microui's demo.

• 19/08/2025: Added support for keyboard input in userspace.

6th month#

• 13/09/2025: Added some disk I/O syscalls.

7th month#

• 20/10/2025: Initial (and half-baked) support for task switching.

8th month#

• 26/11/2025: Moved from GitHub to Codeberg.

• 29/11/2025: Implemented a userspace libc.

• 30/11/2025: Crash handling for userspace processes.

9th month#

• 05/12/2025: Prototyped a desktop environment using Claude Opus 4.5.

• 05/12/2025: Implemented address space separation between processes.

• 06/12/2025: Removed the kernel text console.

• 08/12/2025: Implemented userspace malloc, realloc and free.

• 22/12/2025: Refactored mouse/keyboard input syscalls to use event polling instead of callbacks.

• 28/12/2025: Implemented scheduling.

10th month#

• 05/01/2026: Implemented libgfx.

• 15/01/2026: Rewritten the desktop.

• 19/01/2026: Initial IPC implementation.

• 30/01/2026: Add support for drawing the wallpaper.

• 31/01/2026: Implement proper framerate locking.

11th month#

• 15/02/2026: IPC refactoring and optimization.

• 21/02/2026: Added support for shared memory.

12th month#

• 03/03/2026: Initial work on the libdesktop window protocol.

• 04/03/2026: Desktop performance optimization.

• 06/03/2026: Added support for mouse/keyboard events to libdesktop.

• 06/03/2026: Ported Doom.

• 12/03/2026: More performance optimization for the desktop.

What's next?#

This was the result of twelve months of work on this project. Despite being busy with many other things, I achieved a decent amount of progress and had a lot of fun doing so!

There's a still a lot of work to be done on this operating system in the next year, including (but not limited to):

• A UI framework.
• A software packaging format.
• Disk drivers.
• File systems.
• Permissions/Capabilities.
• More improvements on the desktop.
• More desktop apps.
• SMP.
• PCI drivers.