Optical Storage Mediums The most common way of storing data in a computer is magnetic. We have hard drives and floppy disks (soon making way to the CD-ROM), both of which can store some amount of data. In a disk drive, a read/write head (usually a coil of wire) passes over a spinning disk, generating an electrical current, which defines a bit as either a 1 or a 0. There are limitations to this though, and that is that we can only make the head so small, and the tracks and sectors so close, before the drive starts to suffer from interference from nearby tracks and sectors. What other option do we have to store massive amount of data? We can use light.