One month ago, I saw someone's hobby OS and thought: "I want to build one too."
One month later, nefuOS runs a browser, a compiler, a package manager, and a local LLM.
What it is
nefuOS is a full OS stack written from scratch:
- Ncore — custom kernel, boots via both BIOS (El Torito) and UEFI (GRUB multiboot2)
- Nbrower — custom browser with HTML/CSS/JS/WebGL2, own TLS 1.3 stack
- nefucpp — C++ → .nefud compiler
-
NPKG — package manager over HTTPS, installs
.deb-style packages - Nshell — 60+ Unix-like commands
- Ngame — 34 built-in games
- NAI — a fine-tuned Qwen2.5-1.5B that actually calls tools (writes files, runs commands)
- Chinese IME, TTF rendering, 107 built-in apps
Screenshots
The workflow: one dev + AI
This was the interesting part. I hand-wrote the first ~120k lines (kernel, VFS, IPC, the core architecture). Then I let AI fill in the implementation details — about 80% of the rest.
Architecture, decisions, and debugging are mine. AI just made the typing faster.
- Self-developed: ~215k lines (C/C++ ~192k, Python ~24k)
- With third-party: ~1.04M lines
- One month
The hard parts
- BIOS + UEFI dual boot — same kernel, two boot paths, one codebase
- TLS 1.3 from scratch — for the browser to talk to real sites
-
QuickJS 2021 bugs — the old build crashes on a second
JS_Eval; had to work around it - SWGL — 9000 lines of software GL, needed to run WebGL2 without a GPU driver
What's next
- bloxd.io WebGL rendering (canvas pipeline is almost there)
- Better CSS support (flexbox, descendant selectors)
- DeepSeek login fully wired into the browser
GitHub: https://github.com/Nefu-Dev/nefuOS
Happy to answer questions about the architecture, the AI-assisted workflow, or the dual-backend design.
Top comments (1)
Author here. A few things I couldn't fit in the post:
JS_Evalin the same runtime throws a message-less exception. Had to work around it.Happy to answer anything about the architecture or the AI-assisted workflow.