Oss-it recommends the following free software:
Suitable for most modern workstations, with more than a gigabyte of RAM.
A lightweight version of Ubuntu for older hardware with more than 128 megabytes of memory.
This is a modern lightweight version of Linux for old hardware at the level of 486 processors, to work 48 megabytes of memory is required.
Альт Линукс Лёгкий
The package of free software developed in Russian Federation is popular in educational and state institutions.
We recommend to use on servers (even old outdated workable hardware can be used for a number of server functions: print server, scanning server, local web or file servers, instant messaging server, etc.):
Debian. A popular and fastest growing free software package distribution. Perfect for all server needs.