What is soft and hard computing?
In software developement, where it is used?

Hard computing, i.e., conventional computing, requires a precisely stated analytical model and often a lot of computation time. Soft computing is tolerant of imprecision, uncertainty, partial truth, and approximation. In effect, the role model for soft computing is the human mind.

Mostly crescendo is correct. To me, these terms are only relevant to the definitions of "hard" vs. "soft" computing that are in use by the propagator of the question. IE, you mean apple, and I mean orange when referring to fruit...