The MO disk achieves the rewriting large data on disks like a Floppy disk and a Hard drive by using the combination of a laser beam and a magnetic field.
The MO disk consists of the recording layer and the reflective layer between the dielectric layer and the protective layer over polycarbonate substrate. The dielectric layer enhances the data reading ability and the data is recorded on the recording layer. 5.25 inch MO disk consists of two substrate put together for both sides use.

Spiral Loop
The shape of the track on MO disk is spiral loop which is different from a concentric circle on a Floppy disk or a Hard drive. One groove like a phonograph record is cut at 0.85microm interval.

Non-Contact Recording
MO drive uses magnetic head and optical head for recording.
For magnetic disk drive, magnetic head is directly contacting the disk.
For MO drive, magnetic head and optical head are not contacting the disk.
And there is no concern of a crash of the disk.

Digital Recording
On the magnetic disk, data is recorded in horizontal direction, but on the MO disk, data is recorded in vertical direction.
The data '0' and '1' on the MO disk are identified by the direction of the magnetic field.