Regarding checking for devices, would it be possible to make the
device tree information available to sysctl?  if the structure's
chosen well, subvariables could later be added to indicate other
information (ie, disk geometry, vendor info, perf stats, whatever
other bloat anyone wants and can be bothered to add)

here's a straw-man example (possibly going overboard with the layers,
and excuse the i386-centricism, but i had to pick something):

  dev.isa0.aha0.id0.lun0.type = 0/fixed
  dev.isa0.aha0.id0.lun0.name = sd0
  dev.isa0.aha0.id0.lun0.vendor = QUANTUM
  ...
  dev.isa0.com0.type = 16550A
  dev.isa0.com0.fifo = 1  (16?)
  ...

there's also scope for something like:

  dev.isa0.aha0.irq = 11
  dev.isa0.aha0.iobase = 0x330

All of which is potentially useful information, especially at
install-time for asking the user just which disk I'm really allowed to
scribble.

one more thing that might be nice to take advantage of the mechanism
is (writable):
  
  dev.isa0.ed0.connector = bnc 

Instead of cryptic, inconsistent, and (sometimes) not-well-documented
link0/link0 flags

Clearly, unless it's really trivial and someone who knows how, and has
time to, does it, it won't make 1.1

What do folks think of this as a concept?  How hard would it be to
implement?

--
Dan.