KolibriOS is described as 'Tiny yet incredibly powerful and fast operating system. This power requires only a few megabyte disk space and 8MB of RAM to run. Kolibri features a rich set of applications that include word processor, image viewer, graphical editor, web browser and well over 30' and is a operating system in the file management category. There are more than 50 alternatives to KolibriOS for a variety of platforms, including Linux, Windows, Self-Hosted, Mac and BSD apps. The best KolibriOS alternative is Linux Mint, which is both free and Open Source. Other great apps like KolibriOS are Ubuntu, Debian, Fedora and Arch Linux.
Slitaz is incredibly fast, even on hardware from 2004. It also has a decent software library, so you can set it up for casual internet browsing and document editing without a hassle.