Abstract: A semiconductor memory card is provided that includes: a data storing part; a control part writing and reading data into and from the data storing part; an interface circuit; and a plurality of input and output terminals, wherein data input and output terminal pairs are each allotted to a different terminal pair so that no terminal pair acts as both the data input terminal pair and the data output terminal pair, and a clock input terminal and a clock output terminal are included. The interface circuit receives an input clock from the clock input terminal, receives a complementary input data pair synchronized with the input clock from the data input terminal pair, outputs a complementary output data pair from the data output terminal pair, and outputs an output clock synchronized with the complementary output data pair from the clock output terminal.

Abstract: The optical-disk recording and reproducing apparatus is provided with an optical head, a reproduction circuit, a detector circuit, a servo circuit, a recording circuit, and a controller. The controller among them performs such control that information is recorded and reproduced on only either lands or grooves in a region where file management information is recorded and reproduced, while information is recorded and reproduced on both lands and grooves for a plurality of tracks or for every zone in a data region, in the case of a land and groove recording optical disk. In the case of a land or groove recording optical disk, the controller performs such control that information is recorded and reproduced at alternate tracks in a region where file management information is recorded and reproduced, while information is continuously recorded and reproduced in the data region.