Comment It's at least as much about understanding (Score 1) 1086
When I'm working with someone who's designed a horrible database system and they can't grasp the concept of exponential increases in difficulty (and therefore search time), it's a problem.
I myself have implemented PID controller loops in systems I've developed. I may not have needed 3 years worth of calculus to do it, but I at least had to understand what I was doing and the significance of errors rather than blindly guessing why I didn't have it "right". Most common example of a PID controller people have seen is cruise control in a car. It's not as simple as "if speed preset, press gas harder, else ease off".
Now, that said...where I went, you didn't need any truly hardcore math to get a CS degree...a basic calc class and discrete were about it.