Optical card reading and writing method with redundant directory storage to improve reliability

摘要

In a method of recording and/or reproducing information consisting of directory data and actual data on an optical card having first and second directory data record regions and first and second actual data record regions, the same actual data are recorded in the first and second actual data record regions, the same directory data including position data denoting tracks in the first and second actual data record regions on which the actual data have been recorded are recorded in the first and second directory data record regions. Upon reproduction, at first the directory data recorded in the first directory data record region are read out and if this directory data can be read out correctly, the actual data recorded in the first actual data record region are read out under the control of the position data included in the read-out directory data. If the actual data can not be read out correctly, then the actual data in the second actual data record region are read out in accordance with the position data in the read-out directory data. When the directory data can not be correctly read out of the first directory data record region, the directory data are read out of the second directory data record region, and the actual data recorded in the first or second actual data record region is read out under the control of the position data included in the directory data read out of the second directory data record region.