Abstract: A memory controller includes a data discard controller, calculates a physical address of discard object data designated by a logical address by a host device, and registers the calculated physical address as discard object data information. With respect to a predetermined command from the host device, the data discard controller outputs current discard object data information to the host device. When no command is received from the host device, the data discard controller physically erases the discard object data on the basis of the discard object data information.

Abstract: An information recording medium such as a semiconductor memory card includes a first semiconductor memory having a first recording area accessed by a relatively small access unit and storing file system management information, a second semiconductor memory having a second recording area accessed by a relatively large access unit and storing file data (file entity data), and a controller for controlling the first and second semiconductor memories. The information recording medium selects either one of recording areas of the first and second semiconductor memories depending on the data type, and writes data into the selected recording area.

Abstract: Data is written in data areas (202) and information for correcting an error of the data and status information indicating that the data has been written are written in redundant areas (203) sequentially from the first page of a physical block (201). In the step of creating information to be written in the physical block (201), the redundant areas (203) of the pages are subjected to a binary search to temporarily identify a last valid page. Further, the contents of every area (the data areas and the redundant areas) of the temporarily identified last valid page and a page adjacent to the temporarily identified last valid page are checked to finally identify the last valid page and make a judgment as to whether or not an error page resulting from power-down exists.

Abstract: Data is written in data areas (202) and information for correcting an error of the data and status information indicating that the data has been written are written in redundant areas (203) sequentially from the first page of a physical block (201). In the step of creating information to be written in the physical block (201), the redundant areas (203) of the pages are subjected to a binary search to temporarily identify a last valid page. Further, the contents of every area (the data areas and the redundant areas) of the temporarily identified last valid page and a page adjacent to the temporarily identified last valid page are checked to finally identify the last valid page and make a judgment as to whether or not an error page resulting from power-down exists.

Abstract: An information recording medium such as a semiconductor memory card includes a first semiconductor memory having a first recording area accessed by a relatively small access unit and storing file system management information, a second semiconductor memory having a second recording area accessed by a relatively large access unit and storing file data (file entity data), and a controller for controlling the first and second semiconductor memories. The information recording medium selects either one of recording areas of the first and second semiconductor memories depending on the data type, and writes data into the selected recording area.

Abstract: Areas in an information medium 507 having a plurality of information storing areas 506 which are managed by different file systems are switched by means of a display control part 502 and a medium control part 503, and information for clearly notifying the utilized information storing area 506 from the information medium 507 is displayed on a display part 501. In addition, a switched areas notifying part 508 is provided in order to notify to a user that the area has switched using a mode of display, sound, light or the like.