Patent ID: 6587415
Filing Date: 2003-07-01
Classification: G11B

Abstract:
A drive unit comprising:head means for reading information from a recording medium, decoding means for performing decoding and error correction on information read by said head means, identifying means for identifying whether the information is information from a written area or a blank area on the recording medium when processing is performed by said decoding means on information read by said head means, and control means for verifying the identification result of said identifying means when an error occurs in processing by said decoding means, and performing retries according to said identification result, wherein said identifying means comprises: means for detecting the envelope of an RF signal read by said head means, means for setting an envelope comparison reference voltage, envelope comparison means for comparing an envelope signal, which is output by said detecting means, and the envelope comparison reference voltage, means for multiplying a reproduction clock signal, counting means for counting a comparison signal output by said comparison means by using said multiplied reproduction clock signal, means for setting a blank/written identification reference value, and blank/written count comparison means for comparing the output of said counting means with said set blank/written identification reference value.