Rumsfeld & the closed of the shelf software

Long after Donald Rumsfeld has died, he will be known (sic) for one of the worst quotes ever:

There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don’t know. But there are also unknown unknowns. There are things we don’t know we don’t know.    --Donald Rumsfeld