Multi Device Channel Operation
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2005-Feb-10
This article describes an efficient means to copy data from one I/O device to another. Current channel programs in the IBM System/370 provide for data transfer between main storage (MS) and one I/O device as designated in the Start Input/Output (SIO) instruction. In order to copy data from one I/O device to another I/O device, two channel programs are required (the first to read the data from one I/O to MS and the second to write the data from MS to another I/O device), and some technique to synchronize the two channel programs. The consequence is that a large amount of processor time is consumed handling two SIO instructions for the two channel programs and their ending interrupt processing.