| 摘要 |
PURPOSE:To detect abnormality of an input/output control device at an early stage, and improve reliability of a data processing system, by utilizing an idle state in the course of an on-line operation, and executing a diagnosis. CONSTITUTION:In a diagnosis executing circuit 14 of an I/O control device, when a diagnosis executing instruction is given from a program, an FF19 becomes a set state, and when ''an idle signal'' is informed from an FF18, an AND gate 25 is opened, and an FF20 is set. As a result, an AND gate 22 is closed, start from a channel device is obstructed, also an AND gate 23 is opened, an FF16 is set, and a busy state is informed to the channel device. On the other hand, the program reads whether the FF20 is on or off, after giving the diagnosis executing instruction, and when it is on information showing the diagnostic contents is set to a diagnostic register 21, the designated operation is executed, basing on the diagnostic contents. |
