The formula for calculating disk service time Ts is: Ts = T +L+X Where: T = average seek time L = rotational latency = 0.5/(Disk RPM/60) = 30000/(Disk RPM) X = internal transfer time = (Data block size/internal data transfer rate) Ts = Seek time + 0.5/(Disk RPM/60) + (Data block size)/(Data transfer rate) The formula for calculating IOPS serviced by a disk is: IOPS = 1/TS For performance critical applications disk utilization should be below 70% in this case the value for IOPS is calculated using the following formula: IOPS = 0.7 x 1/Ts Calculate rotational latency for a magnetic disk with a rotational speed of 5400 rpm. Answer: Calculate the disk service time (Ts) for a disk with the following specifications: Rotational speed in RPM: 5400 Average seek time in msec: 6 Data Block Size: 512 Data Transfer Rate MBs: 1189 Answer: Calculate the IOPS for a disk with the following specifications: Rotational speed in RPM: 5400 Average seek time in msec: 6 Data Block Size: 512 Data Transfer Rate MBs: 1189 Answer: