Optical disc

Abstract

To surely write data readably into a region of a designated address even if an unwritten region exists ahead of the designated address. A step of registering beforehand an address map attached to an unwritten region of the data writing area; a step of judging whether an address located ahead of the designated address for writing data is an unwritten region or a written region; and a step of writing data into the data writing area of the optical disc based on the judgment result, are included. In the writing step, if the address located ahead of the designated address is judged as a written region, data writing is performed starting from a region of the designated address, and if the address located ahead of the designated address is judged as an unwritten region, the data writing is performed to unwritten regions including the aforementioned unwritten region.

1 . An optical disc, wherein a data writing area includes: an unwritten region, a written region into which dummy data is written, and a written region into which data provided from a host device is written following the dummy data, and
 the dummy data is trigger data for reading out the data provided from the host device.   
   
   
       2 . The optical disc, as claimed in  claim 1 , wherein a data length of the dummy data is shorter than a length of one block into which the data provided from the host device is written. 
   
   
       3 . An optical disc, wherein a data writing area includes: an unwritten region, a written region in which data including at least one of a synchronizing signal or address information is written in a region of an address located ahead of a designated address, and a written region in which data provided from a host device is written into the region of the designated address, and
 the data including at least one of the synchronizing signal or the address information is trigger data for reading out the data provided from the host device.   
   
   
       4 . The optical disc, as claimed in  claim 3 , wherein a data length of the data including at least one of the synchronizing signal or the address information is shorter than a length of one block into which the data provided from the host device is written. 
   
   
       5 . An optical disc reading method for reading out data which is provided from a host device and is written on the optical disc according to  claim 1 , wherein if the data provided from the host device is written following the dummy data written in the region of the address located ahead of the designated address, the data is read out starting from the dummy data, whereby a timing lag which is caused when the data is demodulated on a rotating optical disc is corrected based on a difference between a reference position of the optical disc and a head position of the data provided from the host device. 
   
   
       6 . An optical disc reading method for reading out data which is provided from a host device and is written on the optical disc according to  claim 3 , wherein the data is read out starting from the data including at least one of the synchronizing signal or the address information written in the region of the address located ahead of the designated address, whereby a timing lag which is caused when the data is demodulated on a rotating optical disc is corrected based on a difference between a reference position of the optical disc and a head position of the data provided from the host device.