What do you mean by “moved a lot”? I assumed the HDD heads are moved to a parking position when the disk is turned off to not accidentally slam into the disks.

What do you mean by “moved a lot”? I assumed the HDD heads are moved to a parking position when the disk is turned off to not accidentally slam into the disks. Portable means the storage has a compact form factor and a case so you can carry it around (turned off). I have never seen anyone actually use a portable disk while moving. Everyone puts them on their desk next to the laptop. The only thing I can imagine is working on a train.