In the literature of Round-Robin scheduling scheme, each job is processed,
one after the another after giving a fix quantum. In case of First-come
first-served, each process is executed, if the previously arrived processed is
completed. Both these scheduling schemes are used in this paper as its special
cases. A Markov chain model is used to compare several scheduling schemes of
the class. An index measure is defined to compare the model based efficiency of
different scheduling schemes.