RFS vs. NFS

[der Mouse]

In article <10219 at steinmetz.steinmetz.ge.com>, stpeters at dawn.steinmetz (Dick St.Peters) writes:
> In article <10186 at ulysses.homer.nj.att.com> ekrell at hector (Eduardo Krell) writes:
>> When I have a network of Suns, Vaxen and other boxes running UNIX, I
>> DEFINITELY WANT UNIX file system semantics on remote files.  [...]
>> This is what is meant by UNIX file system semantics: the behavior is
>> the same whether the file is local or not. It's called transparency.

> It seems to me that "UNIX file system semantics" is not well-defined
> in a network environment, particularly if transparency is the goal.

> Consider RTI's Freedomnet, which RTI advertises as supporting full
> UNIX file system semantics.  However, if program foo physically
> resides on a remote machine, typing foo causes foo to run on the
> remote machine.

This is `transparent' if, and only if, foo would also run on the remote
machine after copying it to some local filesystem.  Otherwise, well,
sorry, their marketing people got ahead of themselves.

> Even under RFS, exec'ing a VAX executeable on a Sun doesn't work very
> well, so it can matter whether the file is local or remote.  RFS thus
> does not support full UNIX file system semantics according to the
> definition ekrell gave.

It doesn't matter whether the file is local or remote; it matters
what's in it!  If you copy the VAX executable to the Sun's local disk,
it doesn't work any better (or worse).  Thus, it *doesn't* matter
whether the file is local or remote.

> It appears that "transparent" and "behaving the same whether remote
> or local" are not equivalent,

Then someone's playing word games.  That's what I always thought (and
continue to think) it means.  That's what I mean when I use it, and
that's what I understand the speaker/writer to mean when I hear/read it.

> and further, neither is adequate as a criterion for the meaning of
> "supports UNIX file system semantics".

Well no, behaving the same whether the file is remote or local doesn't
necessarily imply UNIX filesystem semantics.  UNIX filesystem semantics
are the things specified in the manual: the various calls must work as
they are supposed to.

					der Mouse

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