There are, in fact, several Ubuntu derivatives that might be useful even with hardware that is limited by modern standards. But unfortunately, these distros are not always as easy to use as Ubuntu is and not necessarily as lightweight as some other distributions. I have not myself tested any Ubuntu derivatives but I decided to collect here some information I have encountered on my neverending web searches.
Here are the possibilities I have found:
- U-lite was previously known as Ubuntulite. The web site is not especially uptodate, but earlier versions have according to the information on the site been installed and used with P266 with 192 Mb RAM. At the moment, a processor of Pentium class II, 96 Mb RAM and at least 4 Gb hard drive space are required. More memory would certainly not hurt the system.
- Eebuntu is a remix tailored for EeePC. It comes in three flavours: base, netbook and standard.
- Ubuntu Mini remix is a 133 Mb remix livecd containing only the minimal set of software to make the system work.
- Crunchbang is another lightweight Ubuntu derivative. It is not meant especially for old computers but according to posts in Ubuntu forum many users have been quite satisfied with it even when installed on an old computers.
- Ubuntu Minimal CD Image is one more way to install a lightweight Ubuntu system. See Psychocats for more information about how to build a lightweight desktop around this CD. And don't forget K. Mandla's documentation Set up Ubuntu for Speed.
- More adventurous users might like to try K. Mandla's GTK1.2 remix.
- Fluxbuntu might be active at the moment, at least the web site shows screenshots from the experimental 9.04. The last stable release was based on 7.10 and I was unfortunately not able to install it on my box.
Fortunately, you are free to choose among many free alternatives.