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From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.dcom.lans
Subject: Re: NFS future enhancements?
Message-ID: <1297@hoptoad.uucp>
Date: Sat, 15-Nov-86 17:06:09 EST
Article-I.D.: hoptoad.1297
Posted: Sat Nov 15 17:06:09 1986
Date-Received: Sun, 16-Nov-86 01:41:20 EST
References: <8955@sun.uucp> <12400001@gorgo.UUCP> <42068@beno.seismo.CSS.GOV>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Centram Systems, Berkeley
Lines: 39

I feel a bit strange defending a competitor, but what the hell.  I assure
Rick that there are a lot of mixed-OS networks out there, probably more than
UNIX-only nets.  This means Sun would have to be insane not to try to reach
these customers.  I'm sorry that this doesn't satisfy the needs of one
particular laboratory, but then that lab is free to develop its own
distributed file service products if it wishes.  (In fact, if all you have
is UNIX, you could probably do a perfectly good disk server in a short
time.) Supporting PCs is not some useless crap that just sounds good in ads,
it is a commercial necessity to reflect true market conditions.

As for the alleged non-transparency in NFS because every oddball feature of
UNIX is not supported, again I am on Sun's side.  It is certainly
theoreticaly possible to put the weirdnesses of each operating system into
the file access protocol as optional features, but there are two major
reasons why this can't be done.  First, there's a little thing known as the
N-squared problem.  Second, this really does not preserve absolute
transparency.  After all, UNIX software could be running using files on some
other operating system; if it expects strict UNIX semantics there, then it
will be disappointed.  This gains little if anything.

I think portability constraints alone should prevent people from using local
OS dependencies if there is a portable way to do things.  Why make a temp
file by deleting an open file when you can create a uniquely named temp file
in an almost completely OS-independent way?  Similar considerations apply to
all other operating systems.  You shouldn't ever use the Macintosh ability
to change file dates, for instance.  At some point, one of two things could
happen.  You could decide to port the software to UNIX, which disallows date
changes except by the user from Krypton, or you could be running from a UNIX
file server.

To sum up, there is no absolute transparency in inter-operating-system file
service networks.  It is not possible because of OS differences.  This does
not mean that Sun is lying when they call NFS transparent, or that we at
Centram are lying when we call TOPS transparent.  My living room window has
a few small opaque spots on it, but that doesn't block my view of the bay...
-- 
Tim Maroney, Electronic Village Idiot
{ihnp4,sun,well,ptsfa,lll-crg,frog}!hoptoad!tim (uucp)
hoptoad!tim@lll-crg (arpa)