dorn@fabscal.UUCP (Alan Dorn Hetzel) (10/15/88)
The optical disk in the NeXT system is actually a "magneto-optical" disk. A laser is used to lower the magnetic coercivity of a very small area of the disk, which can then be written by a very weak (and therefore small) magnetic field. The change in magnetic alignment affects the optical properties of the surface, which allows the stored data to be read using a lower power laser. That's the gist of it anyway. Since it spins at RPM's similar to a real hard disk, and since it uses reasonable head transport technology, it can be about the same speed as one (though writing is a little slower, reading should be just as fast) Dorn gatech.edu!fabscal!dorn