[dan-k]

It seems to me like basing patentability on time constraints actually imposes a distinction between hardware and software, regardless of how you feel about their logical interchangeability. For example, an algorithm for real time graphics processing would be just as impractical to run on ENIAC as it would be to do with pencil and paper, but there's no reason you couldn't port the software. So if the validity of the patent is based on its usefulness in a real-time application, it would have to be something like "running algorithm x using computer system y to achieve the desired result in z length of time." Including both the software and hardware used would be the only way to ensure that the time constraint was actually met. I think it's obvious that very few (if any) software patents could meet that criterion.