catflap.org Online Dictionary Query

  go flatline
       
          [{Cyberpunk SF, refers to flattening of EEG traces upon
          brain-death] also "flatlined". 1. To die, terminate, or
          fail, especially irreversibly.  In hacker parlance, this is
          used of machines only, human death being considered somewhat
          too serious a matter to employ jargon-jokes about.
       
          2. To go completely quiescent; said of machines undergoing
          controlled shutdown.  "You can suffer file damage if you shut
          down Unix but power off before the system has gone flatline."
       
          3. Of a video tube, to fail by losing vertical scan, so all
          one sees is a bright horizontal line bisecting the screen.
       
          [{Jargon File]
       
       

  go flatline v. [from cyberpunk SF, refers to flattening of EEG traces
     upon brain-death] (also adjectival `flatlined'). 1. To die, terminate,
     or fail, esp. irreversibly. In hacker parlance, this is used of machines
     only, human death being considered somewhat too serious a matter to
     employ jargon-jokes about. 2. To go completely quiescent; said of
     machines undergoing controlled shutdown. "You can suffer file damage if
     you shut down Unix but power off before the system has gone flatline."
     3. Of a video tube, to fail by losing vertical scan, so all one sees is
     a bright horizontal line bisecting the screen.