A small error, which, if I remember correctly, although it's not mentioned in this account, was in a tiny change that was not tested as fully as it should have

A small error, which, if I remember correctly, although it's not mentioned in this account, was in a tiny change that was not tested as fully as it should have been, took down AT&T's long distance network in 1990, back when it probably still carried most of the nation's long distance calls: http://users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collapse.html http://users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collaps...