KernelUNO v1.0A drops a lightweight, RAM‑based shell onto the humble Arduino UNO. The project offers a virtual filesystem, GPIO handling, and real‑time command execution, all within the 32‑bit ATmega328P’s limits. Users interact through a serial console, issuing familiar Unix‑style commands like ls and mkdir while the firmware stays under 38 % of the 32 KB flash.

Originating from the Arc1011 GitHub repo, the shell fills a niche for developers needing a quick, in‑board terminal without external storage. By simulating a filesystem in RAM, it eliminates EEPROM wear and allows instant file manipulation, while GPIO commands give direct access to the board’s 14 I/O pins—useful for prototyping or teaching embedded concepts.

KernelUNO’s firmware fits within 38 % of the 32 KB flash, consuming roughly 85 % of the 2 KB SRAM, while supporting a maximum of ten files or directories, each capped at 32 bytes of content. A 32‑byte input buffer and safe path concatenation guard against overflows, and a 6‑message dmesg log timestamps kernel events in real time.

The project is released under the BSD 3‑Clause License, encouraging community contributions. Developers can clone the repo, flash the sketch via the Arduino IDE or arduino‑cli, and experiment with built‑in commands like gpio vixa 10 for a quick LED disco test. Future plans include EEPROM persistence and SD‑card support, expanding its utility beyond a simple shell.