The paper investigates in detail a single server single queue time-sharing system with homogeneous Poisson arrivals and exponentially distributed service times. The important variables affecting the design and operation of the system were investigated, and the results are given in terms of steady-state expectations and distribution transforms. An attempt is made to demonstrate the influence of various systems's parameters on the overall performance. Special attention is given to optimisation with respect to quantum size. It is hoped that some of the results may serve as guidelines in the design and operation of time-sharing systems.