Answer
The point to remember here is that the slowness of mechanical motion compared with the speed of the internal functioning of the computer dictates that we minimize the number of times we must move the read/ write heads. If we fill a complete surface before starting the next, we must move the read/write head each time we finish with a track. The number of moves, therefore, is approximately the same as the total number of tracks on the two surfaces. If, however, we alternate between surfaces by electronically switching between the read/write heads, we must move the read/ write heads only after each cylinder has been filled.
Work Step by Step
The point to remember here is that the slowness of mechanical motion compared with the speed of the internal functioning of the computer dictates that we minimize the number of times we must move the read/ write heads. If we fill a complete surface before starting the next, we must move the read/write head each time we finish with a track. The number of moves, therefore, is approximately the same as the total number of tracks on the two surfaces. If, however, we alternate between surfaces by electronically switching between the read/write heads, we must move the read/ write heads only after each cylinder has been filled.
