Hi,

on the web page

  http://www.netbsd.org/Documentation/network/netboot/files.html

the steps to set up the client file systems for booting over the net
say:

  6. Set up swap:
  # mkdir /export/client/root/swap
  # dd if=/dev/zero of=/export/client/swap bs=4k count=4k
  
and further down:

  #/etc/fstab
  nfsserver:/export/client/swap   none  swap  sw,nfsmntpt=/swap
  ...

After a bit of searching I found the explanation for 'nfsmntpt' in
swaptcl(8). However I still do not see the need for this option. What
benefit do I get from having the swap file available on the client as
'/swap'?

Diskless(8) seems to be more clear by suggesting to create the swap file
inside the client root file system and just mount it as

  /swap none swap sw

but I can see, this might have been a problem in times when a 16MB swap
file in the root partition took away valuable space.

ciao
     Klaus