Performance is an important aspect of software composition (see section 3.2.12): two separately fast components, when combined, can be very slow—a bit like two motors working against each other when coupled. The exact effect of composed components on overall performance is hard to predict accurately for complex software systems.
Another common terminology is calling both groups hackers but distinguishing between "white-hat" and "black-hat" hackers. Black-hat hacker is synonymous with cracker as used here.
The literature refers to these as S-type and E-type programs (following the classification of music into serious and entertainment classes), but we substitute these more descriptive names here.