Abstract: Different types of multiple disks are accommodated in a disk package (P) which is loaded into a disk device. Identification means (20) is provided on a bottom plate (1f) of the case (1) of the disk package (P). This identification means is made up of a jumper card (21) embedded in the case and four bits of identification holes (22a, 22b, 22c, 22d); therefore it can offer 4.times.2 sorts of information depending on whether each of the identification holes is opened or closed. The disk device detects that information and obtains information about the types of the disks in the package.