MG1 S,OS, expected value and variance, respectivel of the lst service time in a busy period 230S expected value and variance, respectively, of the 2nd all succeeding service times in a busy period p=l-P= fraction of time server is busyM/G/1 S1 of the 1st service time in a busy period S2 of the 2nd λ ρ ,σ S1 2 = expected value and variance,respectively, ,σ S22 = expected value and variance,respectively, & all succeeding service times in a busy period S2 < 1 =1 − P0 = fraction of time server is busy