processes that get stuck

[Gilligan]

  While we're all discussing defunct and exiting processes, how about
that SunOS 4.x that sometimes puts processes in permanent disk wait?
Processes show up with a D in the STAT field of a ps -gux.  These
processes are unkillable and can only been removed with a halt and a
reboot.  They tend to collect other processes as well.  If you ever
put an emacs into this totally-hosed-state it is quite likely that any
others you start up after it will follow it into D-space.
  I have on occasion been using X windows and watched the xload
skyrocket to 15 as all my shells and compilations go to hell.  The
L1-a is the only solution.
  It hasn't happened as much since we got 8 megs of ram for all of our
computers.

  Comments? explanations?
--
( My name's not really Gilligan, It's Robert Forsman, without an `e' )