Knowing What you Have

In the year that has passed since the I-30 bridge collapse in Minneapolis, inspectors have struggled to doublecheck every bridge that had the same steel deck truss design.
The Federal government had a National Bridge database using data compiled from the states which showed 756 bridges of that structure. MSNBC reports that as inspectors began their process they found that 280 of those bridges weren’t of that design at all.
Some of the bridges had been torn down years ago. Others were misclassified and were actually privately owned (not subject to inspection) A pedestrian bridge made the list as did 13 bridges using wood timbers.
With the data so faulty, how many bridges of this design were miscategorized and thus not given the emergency re-inspection?
Obviously the same holds true in the world of computers. The old adage “you can’t patch what you don’t know you have” is still true. You can’t even watch out for vulnerabilities in things you don’t know you have.