A peripheral digital storage device has an interface allowing a connection to a self-service machine for performing maintenance operation to the self-service machine. The device provides a storage area divided into a set of partitions which are interpretable by the self-service machine as independent storage areas for file operation when connected to the self-service machine. A control unit which is configured to control the access to the partitions by refusing or granting the self-service machine an access to the partition depending on identity information receivable from the self-service machine for providing access to individual partitions for each assigned self-service machine connectable to the interface.