| 摘要 |
PURPOSE:To facilitate checking of read after write data by comparing check data prepared from data transferred from a host device with check data prepared from data transferred from a low order device. CONSTITUTION:Data W of 9-bit width from a channel device 20, a host device, are inputted to a magnetic tape controlling device 10, made to data W of 18-bit width adding check character and transferred to a magnetic tape device 30, a low order device. These data are written in the device 30 and read out immediately, and this read after write data R are transferred to the device 10. Check character prepared from data transferred from the device 20 and check data prepared from the read after write data are compared and it is decided whether the read after write data are correct or not. Thus, by increasing the data width transferred from the host device to the low order device by plural times, checking of the read after write data can be made easily. |
