Define seek time and rotational latency

Sure, let's define these two terms related to hard disk drives:

1. Seek Time: Seek time is the amount of time it takes for the hard drive's read/write head to position itself over the track where data will be read from or written to. It's essentially the time taken to move the disk arm to the desired disk track. The seek time can vary depending on the distance the head needs to move and the speed at which it can move. Lower seek times are better as they mean data can be accessed more quickly.

2. Rotational Latency: Rotational latency, also known as rotational delay, is the delay waiting for the rotation of the disk to bring the required disk sector under the read-write head. It is the time taken for the desired sector of a disk to rotate into position under the read/write head after the head has been positioned at the correct track. The average rotational latency is typically calculated as half the time it takes for a full rotation of the disk. Like seek time, lower rotational latency is better as it means data can be accessed more quickly.