samba - Apr 1998 - Browsing across subnets - some more problems (PR#6450)

>> - Why does nmbd appear to be running twice on some machines?
> 
> nmbd, like smbd is a "fork and exec" daemon.  When a new request
comes
> it, it forks.  This new image deals with the request, while the parent
> process waits for new requests.
nope, not at all.

nmbd is a "one process handles all requests" daemon. You see two
daemons
because at startup nmbd forks so that it can have a separate "asynch
DNS" server. This is to overcome the problem that gethostbyname() is a 
blocking call. If you run netscape on a unix system then you will see
that it too has two processes for exactly the same reason. In general
this is the only reasonable way to do asynchronous DNS lookups on unix
systems.

nmbd uses some quite smart internal queueing mechanisms to overcome
the fact that it is a single process handling lots of simultaneous
requests. It can't use this for gethostbyname() though.

smbd on the other hand is a "fork for each connection" daemon 
(no exec involved, just a fork) so you see a new smbd for each client 
connected to your system.

Cheers, Andrew
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Andrew Tridgell                            Dept. of Computer Science
email: samba-bugs@samba.anu.edu.au         Australian National University 
Phone: +61 6 254 8209                      Fax:  61 6 249 0010
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