because processor time is
shared among multiple users. In a time-sharing system, multiple users simultaneously
access the system through terminals, with the OS interleaving the execution of each
user program in a short burst or quantum of computation. Thus, if there are n users
actively requesting service at one time, each user will only see on the average 1/ n
of the effective computer capacity, not counting OS overhead. However, given the
relatively slow human reaction time, the response time on a properly designed system
should be similar to that on a dedicated computer.