PURPOSE: To obtain the titled controller which contains a data processing system made of small-sized machine and is suited to the use of users, by distributing numbers of cassettes back and forth, left and right and upper and lower parts of the controller and at the same time adding a read/write head which can move in a 3-dimensional way.

CONSTITUTION: The (q×p) units of cassettes 16 are distributed back and forth and left and right of a controller and held above and under the (r) stage. A sector frame body 15 is guided by the guide rods 7, 12 and 2 to the upper and lower parts, left and right and back and forth respectively to a frame having a cassette non-existing space 17. Then a read/write head, a tape driving capstan and a mobile arm which are mounted on the body 15 are actuated when the body 15 is set opposite to a cassette 16 to be selected. Thus the read/write is carried out to a magnetic tape o the cassette 16. In such way, numbers of cassettes are arrayed close to each other and in a rectangular parallelepiped. Thus a data processing system for compartively small-sized machine is incorporated into a concentrated controller of magnetic tape which is suitably used by users.