Blimey, all I wanted to know and more! Thanks.
I still get the feeling that we are becoming slaves to technology though.
I was held up at Dover for over two hours recently because the P&O booking computer crashed. They couldn't get anyone onto the ferries. The traffic was queuing up the hill out of Dover and because of that traffic people sailing with other companies couldn't leave either.
I was near the front of the traffic and on talking with various port employees it turned out P&O don't really have a Plan B for when their computer goes TU.
In the future, if we become over-reliant on GPS and it is suddenly turned off, how would the airline industry cope? Easily? With difficulty?
Not panicking, just wondering.