April 6, 2026
Tiny OS, big drama
Show HN: Anos – a hand-written ~100KiB microkernel for x86-64 and RISC-V
Tiny hand‑made OS drops, devs cheer — then roast the name
TLDR: A 100KB hand-crafted microkernel called Anos now multitasks on real hardware and supports user-space drivers. Comments oscillated between applause for learning-focused hobby OS projects, digs at the name’s Spanish mishap, and a mini culture war over whether AI makes this work obsolete—spoiler: many say no.
A new hand‑written, ~100KB “toy” operating system kernel called Anos just hit the scene, and the internet did what it does best: clap, clown, and clash. The project claims a tiny core (a “microkernel,” basically the minimum brain of an OS) that already juggles multiple tasks across up to 16 CPUs, runs drivers in user space for safety, and even boots on real machines. It targets modern PCs and RISC‑V boards, and it’s proudly non‑POSIX (translation: it doesn’t copy the usual Unix rules). Ambitious, nerdy, and shockingly small — and yes, free under GPLv2.
But the comments stole the show. Naming drama erupted immediately: “impressive. how do you pronounce it?” asked one user, while Spanish speakers face‑palmed at the “unfortunate name,” and another guessed the author “is not a Spanish speaker :p.” Meanwhile, a bigger debate broke out: Are hobby OS projects still useful in the age of AI? One voice pushed back hard, calling today “an age of AI overinvestment” and defending projects like this as priceless for learning. Others nodded to the author’s pedigree (“Roscopeco… behind rosco‑m68k”), signaling this isn’t a weekend fling. Between giggles about the name and praise for the clean, capability‑based design (think: tightly controlled permissions), the thread reads like peak HN energy — equal parts applause, side‑eye, and wordplay. The TL;DR mood? Tiny OS, big reactions, and an even bigger reminder that builder energy is very much alive.
Key Points
- •Anos is a GPLv2-licensed, non-POSIX hobby OS for x86_64 and RISC-V with a STAGE3 microkernel and SYSTEM user-mode supervisor.
- •It supports user-mode preemptive multitasking on up to 16 CPUs, userspace drivers, and runs on real hardware.
- •Kernel features include timers (HPET, TSC, SBI), interrupts (LAPIC, MSI/MSI-X), 48-bit memory management, scheduling, and zero-copy synchronous IPC.
- •Syscalls use a small interface with a fast path (SYSCALL/SYSRET on x86_64, ecall on RISC-V) and a deprecated slow path (int 0x69), governed by capability delegation.
- •Userspace services include VFS, PCI/AHCI drivers via capability-based MMIO, terminal/logging, networking, GUI, and WIP USB (xHCI); minimum x86_64 baseline is Haswell.