[ih] Unix vs. Multics (was - Re: what is and isn't the web, was Rise and Fall of the Gopher Protocol)

John Levine johnl at iecc.com
Mon Aug 22 18:14:24 PDT 2016

>The Multics file system supported multiple names per node, with
>primitives for adding and deleting names, asking about all of the
>names at a particular node, etc.  Those names were true synonyms:
>anything that could be done with one could be done with any of the
>others.   Unix, of course, does not -- the only way to simulate a
>synonym is with links.

Unix systems have hard links, which are fully synonymous names for the
same file, and soft links which are like CNAMEs.  You can add and
delete links easily enough and ask how many names a file has, but
there is no way to find all the links for a file short of enumerating
all the names in the file system.

Early Unix only had hard links.  Soft links were I think a Berkeleyism
added with the motivation being that all the hard links to a file had
to be on the same file system, and in those days file systems were
pretty small.

> However, we ended up with the
>same "one name per node" in the DNS.  I have no information whether
>that was following the Unix model or independent discovery of the
>simplicity-related reasons.

It wasn't the Unix model, but there were certainly plenty of operating
systems that worked that way.  I'd guess TENEX was the likely culprit.


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