The US Navy's warfare systems command just paid millions to stay on Windows XP

USS Yorktown dead in water after divide by zero

http://catless.ncl.ac.uk/Risks/19.88.html#subj1.1

"The Navy's Smart Ship technology is being considered a success, because it has resulted in reduced manpower, workloads, maintenance and costs for sailors aboard the Aegis missile cruiser USS Yorktown. However, in September 1997, the Yorktown suffered a systems failure during maneuvers off the coast of Cape Charles, VA., apparently as a result of the failure to prevent a divide by zero in a Windows NT application. The zero seems to have been an erroneous data item that was manually entered. Atlantic Fleet officials said the ship was dead in the water for about 2 hours and 45 minutes. A previous loss of propulsion occurred on 2 May 1997, also due to software. Other system collapses are also indicated."

I expect this came from Congress' requirement that the military use "Common Off the Shelf Computers" rather than designing new computers for every application.

While I support the use of common computers, it is just plain stupid to use a the kind of computing product that is sold to consumers.

This is exactly what happens when one buys software system without its source code.