Having a robot juggling the hard drives would not make that much sense. The reason why we have optical disc and tape robots is that the tape and discs need a separate device that reads/writes them. With hardware there's not such need.
With hard drives it would make more sense to do some development on the electronics side and build a system where lots of drives can be simultaneously connected to a small controller computer. All of the HD's don't need to be powered on or accessible all the time, the controller could turn on only few of them at a time. And of course also part of the controllers could be normally powered off, once all the harddrives connected to them are filled.
With hard drives it would make more sense to do some development on the electronics side and build a system where lots of drives can be simultaneously connected to a small controller computer. All of the HD's don't need to be powered on or accessible all the time, the controller could turn on only few of them at a time. And of course also part of the controllers could be normally powered off, once all the harddrives connected to them are filled.