In some email I received from matthew green, sie wrote:
   [...]
   > sometimes the kernel image isn't available to the NetBSD userland
   > at all.  eg, a shark netbooted kernel doens't have to exist in
   > the machine's / at all.  i might have loaded my kernel over the
   > ethernet and then used a local root filesystem...  so while you can
   > add to the times when this _is_ available, you can never make it
   > always possible.
   
   Netbooting always seems to be the "forgotten child".
   
   The problem here is that it _may_ be the same or it _may not_, with no
   rule of thumb either way.  The safest thing might be to err on the side
   of caution and just have netbooting pass the kernel a null kernel name
   rather than what it's loaded


it's not just netbooting.  see macs, for instance.  the point i was
making is that you can never in all cases know.  i guess the null
kernel will be OK in these cases...but isn't all this moot with a
/dev/ksyms?