| 摘要 |
PURPOSE:To make it possible to detect accurately an information block position where an error has occurred by performing processing by making comparisons between information block sequence numbers and intra-block logical code word lengths before and after information is written by a magnetic tape unit. CONSTITUTION:Block detecting circuit 1 detects block sequence number NA and block word length LA from an input information block and stores them in memory circuits 2 and 3. The information block, after being written on a magnetic tape by write control circuit 4, is read by reading circuit 5, whose output is input to block detecting circuit 7. Circuit 7 detects number NA and word length LA and stores them in memory circuits 8 and 10. Numbers NA in circuits 2 and 8 are compared with each other by coincidence circuit 13 and the count value of block sequence counter 9 is compared to the output value of circuit 8 by coincidence circuit 14. Word lengths LA in circuits 3 and 10 are also compared to each other by coincidence circuit 16 and the count value of block length counter 11 is further compared to the output value of ciruit 10 by coincidence circuit 17. When even one of four coincidence circuits generates a dissidence output, a decision on an error is made and that is reported to a host unit together with number NA. |
