| 摘要 |
PURPOSE:To execute a chaining check by use of a comparing circuit consisting of a simple structure, by checking whether a readout address register and a write address register are in coincidence or not, at a coincidence time point. CONSTITUTION:A byte counter value (n) of a channel control word CCW1 is set to a terminal register END, and a read input/output operation is executed. When the register END coincides with a register MSA, a request for instructing a data transfer and chain data is sent out to a CPU. As a result, the next channel control word CCW2 is fetched, and when data of quantity designated by the control word CCW2 is stored in a main memory, a comparing circuit COMP1 outputs a coincidence signal. At this time point, if a comparing circuit COMP2 shows dissidence, a chaining check signal of ''1'' is generated. |
