November 1, 2025

Plan 9 walked so CharlotteOS could run?

CharlotteOS – An Experimental Modern Operating System

Rust-built rebel OS sparks cheers and eye-rolls: “not Linux” vs “what’s modern”

TLDR: CharlotteOS introduces a Rust-built kernel with web-style addresses for system resources and strict, capability-based security. Comments split: fans cheer a non-Linux path, skeptics mock the “modern” tag with Plan 9 jokes, and pragmatists share a [better intro](https://github.com/charlotte-os/.github/blob/main/profile/README.md).

Meet CharlotteOS and its Rust-made core, “catten,” a bold indie kernel that promises a fresh take on how your computer manages stuff. The devs talk about using web-style addresses (URIs) to reach system resources—even across the network—locked down by capability-based security and mandatory rules. There’s a better intro floating around, and the vibe is: not another Linux clone, please. Early days, x86 PCs only, contributors welcome on Discord and Matrix.

The comments quickly split into camps. The cheer squad loves the non-POSIX direction and wants alternatives to the big brands. One fan basically says they’re tired of Linux’s multi-user, file-everything ways and want new ideas. The skeptics roll in with: what’s “modern” about referencing Plan 9, a system old enough to rent a car? Cue memes like “Plan 9 is older than my router” and “modern like your dad’s mixtape.” Meanwhile, security nerds are thrilled that capabilities + mandatory access control is becoming standard—“the new normal,” they say, polishing their threat models. Some snark lands on the strict language policy (Rust yes, C maybe, others nope) as “Hogwarts forbidden spells,” and a few side-eye the PC-only requirements. Verdict: an ambitious OS with big ideas and bigger comment drama—bring popcorn.

Key Points

  • Catten is a monolithic kernel for the CharlotteOS project, influenced by exokernel ideas and systems like Plan 9 and Fuchsia.
  • It features a typesafe URI-based system namespace enabling local and remote resource access without mounting, secured by capabilities and persistent mandatory access control.
  • The kernel is written in Rust and x86_64 assembly (Intel syntax via rustc and llvm-mc); vetted C dependencies are allowed, with a preference for Rust equivalents.
  • Target requirements include x86_64 with x2APIC LAPIC, UEFI and ACPI, ≥128 MiB RAM (1 GiB recommended), and ≥4 GiB storage (64 GiB recommended).
  • Supported I/O includes NVMe, USB Mass Storage, UEFI GOP display, NS16550/USB CDC ACM serial, PS/2/USB HID input, and USB CDC NCM networking; the project is GPLv3 licensed and open to contributors.

Hottest takes

“kudos for trailing other paths, and not being yet another POSIX clone” — pjmlp
“So, what’s modern about it? ‘novel systems like Plan 9’ is quite funny because Plan 9 is 30 years old.” — ofrzeta
“It’s comforting to see that capabilities with mandatory access control have become the new normal.” — kragen
Made with <3 by @siedrix and @shesho from CDMX. Powered by Forge&Hive.