A computer program product for performing input/output (I/O) processing is provided. The computer program product is configured to perform: obtaining information relating to an I/O operation at a channel subsystem; generating and storing in local channel memory at least one address control word (ACW) specifying one or more host memory locations for data transfer and including a data check word generation field and/or a data check word save field; responsive to receiving an input data transfer request including at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted; and responsive to receiving an output data transfer, generating at least one data check word based on the data check word generation field and appending the at least one data check word to the data.