"General-purpose free operating systems like Fedora, Debian,
Ubuntu, Gentoo, FreeBSD, and OpenBSD are extremely customizable.
You can slim them down or fatten them up as needed. However,
they're much harder to slim down than they used to be, and far
easier to fatten.
"For most part, you'll need at least 500 MB of disk space just
for the operating system, a Pentium II or equivalent CPU, and 32 MB
of RAM if you don't run X Windows. 64 MB of RAM is a bare minimum
if you run a lightweight window manager like TWM or IceWM; don't
even try to run KDE or Gnome on less than 256 MB..."