Likely it means that with the same input arguments the end result is bit-by-bit identical. (As I understand the problems were hard to control output elements. S

Likely it means that with the same input arguments the end result is bit-by-bit identical. (As I understand the problems were hard to control output elements. So it was not enough to se the same args, set the same time, and use the same path and filesystem, because there were things that happened at different speeds, so they ended up happening at relative different elapsed times, so the outputs contained different timestamps, etc.)