The main characteristic of real - time systems is the correctness of the computation . this correctness does not only to errorless computation , but also on the time in which the result is presented [ sr89 ] 實時系統(tǒng)的主要特征是計算的正確性,這種正確性不僅指計算結(jié)果,而且應(yīng)在時間約束之內(nèi)完成計算[ sr89 ] 。