I wasn't thinking about these markets, but their mere existence proves perfect software can be written - it's possible.<p>What I was thinking was the bold statement that doing something right (or perfectly right) is impossible and its widespread use as an excuse for not even trying. A software developer must aim for perfect software, even if shipping it is not always economically viable. The fact end-users have been beaten into submission and now tolerate having to restart their computers after software crashes or to redo calculations because the results were absurd the first time is not relevant to this discussion. If they tolerate less than correctness, we shouldn't. The current security problems we have are entirely fault of people who regard immediate profit as more important than long-term quality.<p>And I take exception with anyone who suggests this is how things should be.