Actually, the second category should be differentiated further: 2.1) Solving information problems. What you describe. 2.2) Solving physical/mathematical probl

Actually, the second category should be differentiated further: 2.1) Solving information problems. What you describe. 2.2) Solving physical/mathematical problems. Think signal processing. Think physical simulation. The bulk of the code is based on some mathematical theorem or linear algebra that is just too complex to be calculated by hand. The UI is just the surface. The 2.2 group seems a bit more selective. Applications like audio workstations, simulation grids or wheather forecast centers need this. Universities use this for research. While these two groups aren't completely exclusive, I'd say many CS graduates lack the engineering/mathematics/physics prowess needed for the problem spaces encountered in 2.2.