Storage device mounted in portable data storage media type cartridges

A data storage cartridge having an data storage device, such as an encased magnetic disk drive assembly, is, in one embodiment, of generally an exterior dimensional form factor of a tape cartridge having a leader block with a hole therethrough for engagement by a threading pin. To distinguish the cartridge from a tape cartridge, the cartridge shell comprises a blocking portion at the location of the leader block hole. A transfer station both identifies the cartridge and indicates the presence of the cartridge at an end of travel in a cartridge receiver, employing an optical source and an opposed sensor directed toward the leader block hole when a cartridge is at the end of travel. In another embodiment, an encased magnetic disk drive assembly is supported and mounted in a cartridge shell by a shock mount. A flex cable interconnects the rear of the encased magnetic disk drive assembly with an external data transfer interface at the opposite side of the cartridge for data transfer with respect to a transfer station and to provide mechanical isolation.