| 摘要 |
PURPOSE:To make it possible to correct data even if a controller has not any large buffer memory, by detecting a read error and then by finding and atoring the error position and error pattern by error correction code ECC. CONSTITUTION:When data which can be corrected are detected by data part R1D of record 1, the position relative to an error byte and the error pattern are computed by the content of ECC of R1D, and the position relative to the error byte is founed on reference to the content of ECC generator 19 and stored in error byte counter 7. The error pattern, on the other hand, is stored in error-pattern shift register 13. Next, the controller positions the read head to R1D and sets the data length of R1D to data-length counter 6, thereby transferring data of R1D. At every byte time, counter 6 has its content subtracted by the output of counter 5 until a value equal to that of counter 7, and then, FF 11 is set to drive register 13, thereby correcting the error byte. |
