In CMSTPF, each programmer is provided with a private, simulated TPF system for testing his or her TPF application programs. This private TPF system assures that the data and programs for each tester are isolated from the data and programs of other testers.

This isolation means that one tester can't "step on" the testing environment of any other tester. Programmers who have had lengthy testing sessions ruined by another person's errant test know how crippling such an event can be to productivity.