[TUHS] core

[Doug McIlroy]

> As best I now recall, the concept was that instead of the namespace having a
root at the top, from which you had to allocate downward (and then recurse),
it built _upward_ - if two previously un-connected chunks of graph wanted to
unite in a single system, they allocated a new naming layer on top, in which
each existing system appeared as a constituent.

The Newcastle Connection (aka Unix United) implemented this idea.
Name spaces could be pasted together simply by making .. at the
roots point "up" to a new superdirectory. I do not remember whether
UIDS had to agree across the union (as in NFS) or were mapped (as
in RFS).

Doug