Mathematics. In C&M courses, the computer is only a tool.
I dreaded taking Calc II. I saw it as a bunch of formulas I needed to know to get through Calc III. C&M certainly made it interesting . . . I don't think I am lacking anything as far as comparing it to a standard calc class. I am able to do things on paper and able to read a calc book and understand, more so that a few engineers who got A's in (traditional) Calc II.
Techs support both the lab machines and the software used in this program.
In the event of a problem, send an e-mail to tech@cm.math.uiuc.edu.