MEMORY DEVICE AND STORING MEDIUM

PURPOSE:To automatically identify the difference of a screen and to drive a memory device by storing front / rear identifying signal data in the specified position of a data storage echanism at least on one side surface of a storing medium in advance. CONSTITUTION:At the time of preparation, a front / rear identification code 3 is recorded in a specified place on one side surface of a disk 1. When the disk 1 is set to an input / output device 20, the disk 1 is rotated and drive by a motor 7 and the front / rear identification code 3 is read by a reading sensor 4 provided by facing to one surface of the disk 1. When the reading sensor 4 does not read the front / rear identification code 3, it is regarded that the disk 1 is set forward. After that, normal input / output is executed. When the reading sensor 4 reads the code 3, it is judged that the disk 1 is set backward. Then, the rotation of the motor 7 is inverted and the connection of one side sensor and the other side sensor to a data input / output part is inverted. Thus, the difference of both sides is automatically identified and the data can be correctly inputted / outputted.