Nightmare File System
Pejorative hackerism for Sun's Network File System (NFS). In any nontrivial
network of Suns where there is a lot of NFS cross-mounting, when one Sun goes
down, the others often freeze up. Some machine tries to access the down one, and
(getting no response) repeats indefinitely. This causes it to appear dead to
some messages (what is actually happening is that it is locked up in what should
have been a brief excursion to a higher spl level). Then another machine tries
to reach either the down machine or the pseudo-down machine, and itself becomes
pseudo-down. The first machine to discover the down one is now trying both to
access the down one and to respond to the pseudo-down one, so it is even harder
to reach. This situation snowballs very quickly, and soon the entire network of
machines is frozen - worst of all, the user can't even abort the file access
that started the problem!
Many of NFS's problems are excused by partisans as being an inevitable result of
its statelessness, which is held to be a great feature (critics, of course, call
it a great misfeature). ITS partisans are apt to cite this as proof of Unix's
alleged bogosity; ITS had a working NFS-like shared file system with none of
these problems in the early 1970s. See also broadcast storm.
[Jargon File]
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