Harddisk constantly active

The Harddisk is contantly active. I hear the noise and feel the movement, also when there is no activity on my PC or tablet. Is that normal? carolus47

Same with mine. I have a constant vibration from the disks spinning, but no fan noise.

I have same problem, why? Any solution?

Same here. Disks are active even if units connected to it are closed.
I would like to know why ?