On Tue, Jan 11, 2000 at 11:22:33AM -0700, Warner Losh wrote:

> Yes.  It is a *WELL* known problem that PC serial ports tend to put
> out a long BREAK sequence while power is coming down, which kicks the
> system into the debugger.

sysctl -w ddb.fromconsole = 0

before you power down your PC... and the decstation should ignore the
break.

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier@poofy.goof.com
  "Time Correct function allows automatically correcting slight variation
   of your key touching manner."  --  Roland MSQ-700 manual