In some research I’m doing for a new course, I ran into Nancy Leveson’s list of myths regarding software safety.  She presented this list in her 1995 book Safeware: System Safety and Computers.  The list of myths are as follows:

1. The cost of computers is lower than that of analog or electromechanical devices.
2. Software is easy to change.
3. Computers provide greater reliability than the devices they replace.
4. Increasing software reliability will increase safety.
5. Testing software and formal verification of software can remove all the errors.
6. Reusing software increases safety.
7. Computer reduce risk over mechanical systems.

We will do well to remember this list as we design complex software based systems.