File open options

[Bernard S. Greenberg <BSG at SCRC-TENEX>]

The Laser Manual speaks of the :IF-EXISTS options :RENAME,
:RENAME-AND-DELETE as though they do their renaming and deleting at open
time.  It goes out of its way to say that :SUPERSEDE "destroys" the
existing file at successful close time.  The former being unreasonable,
I decided that the Lisp Machine local file system would continue to
implement all of these concepts at successful close time.  It keeps the
real file open under a funny name until then.  The only place it could
possibly screw up is a direct access, interlocked, multi-process, shared
file of a kind that we currently don't have.
I guess I'm just thinking out loud, or asking for an adjudication
on the legality of such a decision.

While we are on the subject, should anything be said about open 
':direction ':output ':if-exists ':overwrite closing in abort mode?
Should the file go away?