Driving circuit for driving reading operation of optical drive and method for reading information from optical data storage medium

Abstract

The invention is directed to a method for reading information from an optical data storage medium, operating by: obtaining at least one coding/decoding unit of the optical data storage medium wherein the coding/decoding unit comprises a plurality of codewords; checking if the coding/decoding unit is reliable; and when the coding/decoding unit is not reliable; selecting at least one spec-defined codeword from the plurality of codewords. The spec-defined codeword includes a plurality of spec-defined fields defined by the specification of the coding/decoding unit; checking whether the spec-defined codeword is reliable; and when the spec-defined codeword is reliable, retrieving information from the spec-defined codeword.

1 . A method for reading information from an optical data storage medium, comprising:
 obtaining at least one coding/decoding unit of the optical data storage medium wherein the coding/decoding unit comprises a plurality of codewords;   checking if the coding/decoding unit is reliable; and   when the coding/decoding unit is not reliable;   selecting at least one spec-defined codeword from the plurality of codewords, wherein the spec-defined codeword comprises a plurality of spec-defined fields defined by the specification of the coding/decoding unit;   checking whether the spec-defined codeword is reliable; and   when the spec-defined codeword is reliable, retrieving information from the spec-defined codeword.   
     
     
         2 . The method as claimed in  claim 1 , wherein the step of checking whether the spec-defined codeword is reliable comprises:
 checking whether an error correction result of the spec-defined codeword is successful;   checking whether data stored in the spec-defined fields of the spec-defined codeword conforms to the specification of the coding/decoding unit; and   deciding that the spec-defined codeword is reliable when the error correction result of the spec-defined codeword is successful and the data stored in the spec-defined fields of the spec-defined codeword conforms to the specification.   
     
     
         3 . The method as claimed in  claim 1 , wherein the coding/decoding unit is a disc fundamental information sector reduplicated with copies in several area of the optical disc and the information comprises updating counter, and the method further comprising:
 comparing the updating counter of the disc fundamental information sector with updating counters of other reduplicated disc fundamental information sectors in the optical data storage medium;   when the updating counter of the disc fundamental information sector is less than or equal to any of the updating counters of other reduplicated disc fundamental information sectors, accessing the optical data storage medium according to at least one of the reduplicated disc fundamental information sectors; and   when the updating counter of the disc fundamental information sector is larger than the updating counters of other reduplicated disc fundamental information sectors, accessing the optical data storage medium according to the disc fundamental information sector.   
     
     
         4 . The method as claimed in  claim 3 , wherein the information is DDS, DFL or PAC of BD physical specification or DVD-RAM physical specification. 
     
     
         5 . A method for reading information from an optical data storage medium, comprising:
 obtaining a plurality of coding/decoding units of the optical data storage medium wherein each of the coding/decoding unit comprises a plurality of codewords;   checking if the coding/decoding units are reliable; and   when the coding/decoding units are not reliable;   collecting desired codewords at least from codewords having successful error correction of the coding/decoding units;   combining the desired codewords to form a new coding/decoding unit; and   obtaining information according to the new coding/decoding unit.   
     
     
         6 . The method as claimed in  claim 5 , wherein the step of obtaining information according to the new coding/decoding unit comprises:
 determining whether the new coding/decoding unit is reliable by comparing calculated EDC value and recorded EDC value; and   when the new coding/decoding unit is determined to be reliable, obtaining the information by retrieving data from the new coding/decoding unit.   
     
     
         7 . The method as claimed in  claim 5 , wherein the method further comprises:
 generating at least one new codeword which comprises spec-defined data according to the specification of the coding/decoding unit, wherein the value of the spec-defined data is defined by the specification of the coding/decoding unit;   
       and the combination to form the new coding/decoding unit comprises:
 combining collected desired codewords with the new codeword to form the new coding/decoding unit. 
 
     
     
         8 . The method as claimed in  claim 5 , wherein the plurality of coding/decoding units have same format of data and are recorded in different areas of the optical disc according to the specification or according to behaviors of an optical drive. 
     
     
         9 . A method for reading information from an optical data storage medium comprising a plurality of codewords, comprising:
 selecting at least one spec-defined codeword from the plurality of codewords, wherein the spec-defined codeword comprises a plurality of spec-defined fields defined by the specification of a coding/decoding unit;   determining whether the spec-defined codeword is reliable; and   when the spec-defined codeword is not reliable, modifying data stored in the spec-defined fields of the spec-defined codeword according to the specification of the coding/decoding unit to generate a modified codeword, and retrieving information from the modified codeword if an error correction result of the modified codeword is successful.