A set of short answers to your questions:

 * Difference of SUP and CVS: SUP lets you as an end-user get the latest
   versions of a collection of files (e.g., system source files) from a
   central distribution point.  CVS can do this too, but also can be used
   by developers to coordinate updates to the files.  (A little more
   briefly: SUP is a distribution tool.  CVS is a version control system.)

 * If you can't track current versions by relying solely on SUP, then I'd
   like to know why not.  (I use SUP whenever I want to update pkgsrc.)

   Of course, there may be server (or network) load issues involved in
   the suggestion that was made to use CVS for everything after the
   initial SUP.  Perhaps someone will explain this in more detail?


As for your other two questions, I'm not sure offhand.  (Though I would
be leery of trimming even ``extraneous'' or ``port-specific'' files from a
source tree unless I (personally) had inspected the code closely enough to
be sure that the files weren't needed for my uses.  Also, deleted files
will presumably be regenerated when you next update with CVS or SUP---so
if you're planning on tracking -release or -current, trimming your
directory tree may prove to be an exercise in futility.)


  "I probably don't know what I'm talking about." --rauch@eecs.ukans.edu