| 摘要 |
PCT No. PCT/FI96/00572 Sec. 371 Date Apr. 23, 1998 Sec. 102(e) Date Apr. 23, 1998 PCT Filed Oct. 29, 1996 PCT Pub. No. WO97/16786 PCT Pub. Date May 9, 1997In process controlling computers, such as switching exchanges, faults may prove to be very expensive. Particularly hard to solve are software defects. If problems occur, it is important that maintenance can be directed at the correct target as soon as possible. A threat is constituted by vandals and hackers. If the option for maintaining from elsewhere is incorporated in computers, the danger for misuse consequently increases. Prior art techniques for detecting memory problems do not necessarily reveal defects occurring at regular intervals caused by the method of calculation. Memory defects will occur at regular intervals e.g., if an address line of a memory circuit becomes faulty. A second drawback of the prior art is that the checksum has to be calculated anew if the contents of just one storage location change. The method of detecting memory problems according to the invention is "regularly irregular" so that it detects in a reliable manner an uncontrolled change in any storage area (MA). Furthermore, the checksum (CS) calculated according to the method may be updated upon changes of an element in a storage area (MA) so that the updating requires much less calculation than would calculating the checksum over the entire storage area (MA) being monitored. The method is applicable in detecting hardware and software defects and in expediting the restart of a computer. |
