Re: 20th century
>It is very difficult AND expensive to corectly test everything..
Never use the phrase test everything as its impossible to test all inputs as you would need to go to infinity. Say thorough test coverage or some such en vogue nonsense. Sorry to be pedantic but people seem to think truly complete regression is very possible and all security bugs are due to sloppiness testing when that is often but not always the case. Seems to be pretty clear in this case though Microsoft screwed the pooch.