change notify timeout Performance issue

[Peter Samuelson]

[David Collier-Brown]
> I can't speak to the requirements, as I don't grok NT, but I'm
> suspicious about the degree to which NT is asking for notification...

Presumably so it can update the 'Doze Explorer display every now and
then.  Maybe not life-threatening, but not something where you just
want to go "aw, it won't matter".

> In particular I wonder if notify is meaningfull on a read-only share:

Well, if the host has it mounted read-only from a local drive (try
testing portably for *that*!) then yes, it's meaningless.  On the other
hand, if only the client has it read-only, others could be updating it.

I do agree that it would be nice for Unix to support, say, select() on
a directory, to give this sort of information.  (Look, Ma, no new
system call!)  I'm still not sure whether the API should specify that
the kernel reports changes from arbitrary levels deep or just one
level.

Peter