AROS, previously known as AMIGA Research Operating System is a lightweight, efficient and flexible open source desktop operating system, designed primarily for PC.
Native port for ARM is not yet finished but currently, it is possible to run AROS as an ARM linux application. There is also mini debian 8 based distro with AROS as a desktop for Orange Pi (build for Orange Pi PC). Both archives are available for download from this page.
When in 2010 AROS was ported to ARM architecture, Michał Schulz, AROS developer wrote about performance: " Hello again. I though I own you few words of explanation, why is AROS on ARM so interesting... AROS is a lightweight OS. It's core system started up occupies around 5MB of RAM only. It schedules fast (since AROS tasks and processes are either as heavy or even lighter than linux threads) and starts quickly. Memory footprint is very low. Functions in AROS libraries are not resolved by name, but rather by their position in function pointer table. Core AROS applications start within a fraction of second, including their load time and loading of all libraries. Even on linux hosted AROS applications behave and response faster, than native linux software. If you were using AmigaOS, AROS or MorphOS before, you will find the same speed here, on ARM. If you haven't used any Amiga-like operating system before, you have to test it and feel it yourself."
