The access time ofhard disks depends on various parameters, including the control of the access arm with the read/write heads. There are various algorithms for controlling the access arm that have a direct influence on the access time.
In addition to First Come First Served( FCFS), which supports free positioning according to the order of incoming jobs, there is also Shortest Seek First( SSF), a method that always uses the path with the smallest deflection of the access arm. This method significantly improves the access time compared to FCFS.
With Shortest Seek First (SSF), the job whose position is closest to the read/write head is always executed first. On the other hand, this means that data at the edges of the hard disk have relatively long access times, because the positions located in the vicinity are processed first.