3.75MB of storage is the same as a couple of floppies. The video below shows the first hard disk based backing storage unit.

The drive is composed of 50 disks (100 writeable surfaces) each with 100 tracks.

[kml_flashembed movie="http://www.youtube.com/watch?feature=player_embedded" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

Just in case it wont embed, try here