General diskless problems.

After seen some mail about initdiskless, I recall that have some 
problems with diskless/pxe last time.

Maybe of general interest.

- can't mount a NFS root from a tftp operate loader
- can't mount a NFS root froma a BOOTP configured kernel.

This seems related to a bug in the loader/kernel kenv.  Loader pass a 
nfsiohandle via kenv without check.  If the loader doesn't do any NFS 
operation, it's a pretty invalid all zeroes nfsiohandle that messed 
kernel nfsroot mount.

- PXE i/o problems.

intel PXE i/o is NON_BLOCKING.  It is supposed blocking on all the UDP 
code.

Also seems recall a bios I/O buffer configured as a packet buffer.

Sorry.  I missed to report this (think).

--
  josemi