If 500 lines is not enough you will find EMC here: http://www.linuxcnc.org/ It is free and open source.

You do not need a "Unix machine" to run it. It can be downloaded and burned onto a cd to make a "live disk". It comes complete with the Ubuntu operating system (a flavour of Linux) and can be installed to dual boot alongside Windows on a normal PC. One caveat; it doesn't like NVIDEA graphics cards.:sad:

Russell.