| 摘要 |
PURPOSE:To read the contents of a memory freely in a system in which interruption of program execution is not allowed by providing second memory having the same address with a system memory and writable from a common bus and a device that reads out the second memory. CONSTITUTION:A memory 4 has the same address with a memory 3. It monitors the system and only writing is possible from a common bus. A system monitoring device 5 reads the memory 4 and analyses and displays the contents. In ordinary operation of the system data are exchanged between a CPU1 and the memory 3 through the common bus. As the memory 4 is the same address with the memory 3, the same data with the memory 3 are written. Accordingly, the contents of the memory 3 and memory 4 are always the same, and therefore, the contents of the memory 3 can be known by looking the contents of the memory 4. Accordingly, by reading the contents of the memory 4 by the monitoring device 5 when writing is not made in the memory 4, the memory can be monitored without stopping the system. |
