an optical disk driver using a top - loading mechanism is coupled to an operational processor , such as a personal computer . the term “ a top - loading mechanism ” means a mechanism for inserting and / or ejecting an optical disk via a top surface of the optical disk driver . additionally , a display unit used for the operational processor can be located on an operational processing apparatus comprising such an optical disk driver and an operational processor . the optical disk driver includes a first case , accommodated in a housing having the operational processor therein , a second case ; movable from a first position to a second position , the second case projecting from the first case so that an optical disk can be inserted and / or ejected via a top surface of the second case when the second case being located at the first position , the second case being accommodated in the first case to be operatively connected to the operational processor when the second case being located at the second position .