VMS vs. UNIX file system

David Goodenough dg at lakart.UUCP
Wed Sep 21 08:09:36 AEST 1988


>From article <3506 at ihlpe.ATT.COM>, by daryl at ihlpe.ATT.COM (Daryl Monge):
> 
> What I would like in the UNIX file system the VMS system has is the ability
> to break links when a file is written.  I have an application where we wish
> to share information between two directories, but I want the link broken if
> the file is written when accessed from any directory it is listed in.  This
> happens with VMS links because of versions of files in the file system.

You have it. Consider the following:

	% mkdir foo bar
	% cat /etc/passwd >foo/file
	% ln foo/file bar

I now have one file in foo and bar - same data, cause it's a link

	% mv foo/file foo/file.old

Make a new version (o.k. so version numbers don't work so hot, but with a 10
line procedure it can be implemented)

	% update <foo/file.old >foo/file

You now have your new version, PLUS the old original, which is still a link.
In both instances we've done about the same amount of work: in either
instance update is going to have to cause the system to write the new file
completely, but that's life.

Just like you wanted.
-- 
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