From mboxrd@z Thu Jan  1 00:00:00 1970
From: lyndon@orthanc.ca (Lyndon Nerenberg)
Date: Mon, 5 Feb 2018 15:18:09 -0800 (PST)
Subject: [TUHS] Windows roots and Unix influence (was Re: Happy birthday,
 Ken Thompson!)
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> Save design would have the plane controls on a completely air-gapped 
> network from the entertainment stuff.  I was told that they don?t, 
> because the captain needs to be able to stop the entertainment system 
> during an announcement.  I could build them a very simple gateway that 
> transmits UDP packets in one direction only, that would meet this, and 
> related needs.

This doesn't need a network, just a pair of GPIO pins -- an output 
pin on the avionics system, and an input pin on the entertainment system.