The partial installation requires less that half an hour and fewer than 2 megabytes of disk space.  The resource economy comes from the fact that the ZPL compiler itself is not included in the partial installation.  Run-time libraries and configuration files are included, but in order to actually compile a ZPL program, you use a client stub to connect to the ZPL Net-Compiler server, which compiles the program for you.  If you are not sure you want to invest the effort, check out the <a href="http://www.cs.washington.edu/research/projects/zpl/web-compiler">Web-Compiler</a> first.  </p>
