new open keywords?

[Robert W. Kerns <RWK at MIT-MC>]

The problem is that the LISP Machine must interface to a large
number of various file systems with differing capabilities.  The ITS
file server always writes _LSPM_ OUTPUT and renames it on closing.
You can't even create a file with an underscore in its name on VMS,
but the VMS file server doesn't put the file into the directory until
close time.  I cannot imagine why you would want the file to appear
until it is closed and accessible, anyway.  An option to force an
incomplete file to appear under the final filename while it is still
being written would seem to me to be worse than useless.

:DONT-CLOBBER could be useful.  But realize that it cannot be
implemented with full reliability on ITS and perhaps other file
systems.  (It can be on VMS).  The check would have to be done at
CLOSE time (although additionally at OPEN time would be nice) since
you don't want to have an incomplete file there until you're done.