Disk subsystems of soft real-time systems are designed to meet the deadlines of the real-time disk I/O commands as many as possible. This paper examines the methods to get the best out of active hardware components in a disk drive and evaluates the real-time performances of the methods. Some of active hardware components in a disk drive are idle for some time while a disk I/O command is being serviced by some active hardware components in the disk drive. If the idle time would be used for the next pending disk I/O command, the disk I/O command could be serviced much earlier. We develop the three models of overlapped disk access which service two adjacent disk I/O commands concurrently by overlapping. The new disk model embedding the overlapped disk access methods is also proposed in this paper. It is evaluated via simulations, and its real-time performance is compared with traditional disk drives. The results of the performance evaluation show that the proposed disk model gets much better real-time performance than the traditional disk drives in real-time computing environments.