| 摘要 |
<p>PURPOSE:To quickly cope with fault for recovery and version updating by holding program data after revision and the program data before the revision, selecting either one by a simple switching operation and effectively utilizing a software. CONSTITUTION:A first read-only memory 11 for storing the program data after the revision, a second read-only memory 12 for storing the program data before the revision and a memory switching means 13 for selecting either the first read-only memory 11 or the second read-only memory 12 are provided on the same substrate 14. Thus, it is made possible to perform a calculation processing using the program data before the revision and the bug discovery of the newly developed software for control, etc. The troublesomeness of detaching a ROM/ RAM board from an information processor and attaching it again is also eliminated and a countermeasure is quickly taken.</p> |
