code: def _uptime_plan9():
      
      # Apparently Plan 9 only has Python 2.2, which I'm not prepared to
      # support. Maybe some Linuxes implement /dev/time, though, someone was
      # talking about it somewhere.
      try:
          # The time file holds one 32-bit number representing the sec-
          # onds since start of epoch and three 64-bit numbers, repre-
          # senting nanoseconds since start of epoch, clock ticks, and
          # clock frequency.
          #  -- cons(3)
          f = open('/dev/time', 'r')
          s, ns, ct, cf = f.read().split()
          f.close()
          return float(ct) / float(cf)
      except (IOError, ValueError):
          return None
docs: Returns uptime in seconds or None, on Plan 9.