nefuOS: A from-scratch OS with a browser, WebGL, and a local LLM — built in one month

Developer Nefu-Dev released nefuOS, a from-scratch operating system built in one month that includes a custom kernel (Ncore) booting via both BIOS El Torito and UEFI GRUB multiboot2, a custom browser with HTML/CSS/JS/WebGL2 and its own TLS 1.3 stack, a C++-to-.nefud compiler, the NPKG package manager, and NAI, a fine-tuned Qwen2.5-1.5B model that calls tools to write files and run commands. The project totals roughly 215,000 self-developed lines (C/C++ about 192,000, Python about 24,000) and about 1.04 million lines including third-party code, with the author hand-writing the first ~120,000 lines and AI filling in roughly 80% of the remaining implementation. The code is published at github.com/Nefu-Dev/nefuOS.

nefuOS: A from-scratch OS with a browser, WebGL, and a local LLM — built in one month 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. nefuOS is a full OS stack written from scratch: Ncore — custom kernel, boots via both BIOS El Torito and UEFI GRUB multiboot2 Nb 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. 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 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 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 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. Key Takeaways - •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. nefuOS is a full OS stack written from scratch: Ncore — custom kernel, boots via both BIOS El Torito and UEFI GRUB multiboot2 Nb - •This story was reported by Dev.to , covering developments in the dev space. - •AI advancements continue to reshape industries — read the full article on Dev.to for complete coverage. 📖 Continue reading the full article: Read Full Article on Dev.to → https://dev.to/nefu-dev/nefuos-a-from-scratch-os-with-a-browser-webgl-and-a-local-llm-built-in-one-month-l1b