Abstract: For effectively suppressing echo of an electromagnetic wave emitted from an electromagnetic device (24) disposed in a closed space (13) which is defined by a shielding wall (10), an electromagnetic anechoic chamber comprises an absorption member (28) disposed in the space. The wall has an inner surface which reflects the electromagnetic wave into the space as a reflected wave. The reflected wave is directed to a particular position in the space. The absorption member is located at the particular position. Preferably, the inner space is formed along a substantially ellipsoidal shape having a first and a second focus point (14, 16). The electromagnetic device and the absorption member are locsated at the first and the second focus points, respectively.

Abstract: An information storage apparatus (20) used in combination with an information processing device utilizes a plurality of magnetic disk units (22). The units are individually stocked in stocking locations of a stocking device (23). The stocking locations are assigned with different address numbers. On receiving an incoming signal from the information processing device, one of the units loaded into a disk driver (24) by a transporting device (49, 50) and a desired information data is recorded or reproduced on a flexible magnetic disk of the unit. The unit is thereafter returned to the initial location of the stocking device. Each of the units may have a recording medium. A recording and reproducing device (57) records or reproduces address information on the medium of the unit during transportation of the unit.