DATA TRANSFER METHOD

PURPOSE:To provide a data transfer method of high precision without changing a conventional error detection code by comparing the parity obtained from reception data, to which the parity is added, with a retransmitted parity by a transmission destination device to discriminate whether they coincide with each other or not. CONSTITUTION:At the time of transferring data between devices, data to which the parity is added is first transferred to the transmission destination device, and only the parity is next transferred to the transmission destination device again. The transmission destination device compares the parity, which is obtained from reception data to which the parity is added, with the retransmitted parity. If they coincide with each other, the transmission destination device judges that transfer data is correctly transferred; but otherwise, the device judges that transfer data or/and the retransmitted parity are erroneous. For example, in a computer system, a memory device 62 compares and collates the horizontal parity transferred from a CPU device 63 with the horizontal parity generated from reception data by comparing and collating circuit 67, and correct transfer is discriminated in the case of coincidence.