When a ``new model'' for Athena is proposed, it should be described in
terms of the three components described in this document: system packs,
installation software and locker software.  It should be pointed out
where the new model is different.  When there are differences in the
system packs, Figure 1 should be used to illustrate which subsets are
different.  This will demystify the developer's perspective of the new
model.

Of course, the new model should also be described from the user's
perspective, i.e. what the workstation looks like when you login.  A
straightforward change from the developer's perspective may result in a
radically different model from the user's perspective, and vice versa.