Can't get video to play past a few seconds but I have a general idea of what goes on. The reader head goes BRRRRRR. Actually incredible how high tech hard drives are when you think about it. The precision needed for them to work and to always line up at the exact right spot each time and fact that they are available to consumers at a reasonable price and the fact that despite being moving parts last for as long as they do.
I still have a lot of them in service as that's all I go with for mass storage. Recently retired some that were pushing 10 years of continuous operation though but they still work, just wanted to upgrade to bigger ones.