Since the tape libraries have very poor random access performance, it is critical to study random I/O scheduling strategies and algorithms in order to improve the performance of tape library. In this paper, the existing scheduling algorithms are summarized first, and then the analytical results of the effectiveness of static scheduling, dynamic scheduling and replication-based scheduling are presented through simulations. In particular, a benefit-cost-based scheduling algorithm is given, which aims to improve the effectiveness of exosting scheduling algorithms under heavy workloads by tuning the weight ratio of cost and benefit of scheduling policies according to workloads.This algorithm is significantly effective under heavy workloads.The research of this paper forms the basis of the design of adaptive scheduling algorithms that can be used in massiv storage systems.