Abstract: The process, apparatus, and system estimate the size of a data block in a data buffer to efficiently recover the data block to the memory of a computer. The data block resides in a data buffer prior to being written to a destination medium. If the data block cannot be written to the destination medium, the process, apparatus, and system create a data block size estimate. The data block size estimate may be based on the size of the largest data block in the data buffer. Alternately, the data block size estimate may be based on the size of a data block in the memory of the computer. The computer reserves a memory space proportional to the data block size estimate and recovers the data block to the memory space.

Abstract: A fast-acting method of regenerating track crossing signals for track searches across unrecorded areas on read/write optical discs is provided. This is accomplished by comparing the in-phase and quadrature-phase track crossing signals generated by the optical pickup head when a track search is being performed. A blank signal is generated when no quadrature-phase signal transition occurs between two successive in-phase signal transitions. Fake quadrature-phase signals are continuously generated. Upon occurrence of a blank indicating signal, the fake quadrature-phase signals are immediately supplied to the track crossing counter mechanism in place of the missing quadrature-phase signals. As a result, there is no loss of track count.