we are learning how a disk rotates in order to preserve memory on the physical computer hardware. in order for this disk to preserve memory, it has to rotate by following laws of physics as a circular sphere with sine and cosine waves on the coordinate system. these sine and cosine waves that vibrate independently and periodically, which means that the disk rotates 10,000 orbits per second. a drill rotates 2000 orbits per second. 10,000 orbits per second is fast enough to cut your hand off in less than 1 millisecond. we are learning that this disk has to rotate so fast in order to preserve the memory which was stored by the database system with sql.

on a subject called sql databases.