The fatal air gap problem is defined as:
The fatal loss of connectivity, usually network connectivity, which arise due to the presence of an air-gap between the cable and the piece of equipment it is supposed to connect to.
Colloquially: “Its not plugged in”.
Also: “Well of course it isn't working, its not plugged in.
This is a well known phenomenon that I became aware of back in the early days of my computing career, when we were stringing coax cable through Jamz's house, and then spending most of the weekend trying to get it all working. We would be puzzled as to why we could't ping each other, and be checking 50 ohm resistance and so forth. We would restart windows 3.11 again and again, only to find that it wasn't plugged into the hub, or some such thing.
Fast forward to today, about 10 minutes ago.
After spending a few hours trying to get Veritas to see the disk arrays, it finally occurred to me to check the cabling, since we had just moved the machines around. Sure enough, there was a fatal air gap problem.
This one though was slightly different however, it was a case of the fatal power shortage problem, which I hereby propose to be a corollary of the fatal air-gap problem, defined thusly:
The fatal loss of connectivity, which arise due to the shortage of electrical power to the equipment.
Colloquially: “Its not turned on”.