PURPOSE: To precisely and efficiently detect the long invalid holding of a memory buffer, by connecting a chain for using information between memory buffers and periodically monitoring the memory buffer holding time of the leading part of the chain.
CONSTITUTION: When a memory buffer ME newly starting to be used is generated, MD-ME linkage is connected to the end of the last memory buffer MD and the address ME of the memory buffer ME is registered in a tail register 20 to form a using memory buffer linkage for memory buffers MA, MB, MC, MD, ME. When the memory buffer MB is to be released, the linkage between the memory buffers MA and MC is formed. When not released within TIMA, the memory buffer MA linked with a head register 10 is added by a trouble detection processing started at a shorter period than the required TIMA in every starting of the TIMA in a timer register 30, and when the added value is reduced down to ≤0 prescribed value, it is discriminated that the holding time of the memory buffer MA is abnormal.
MARUYAMA MINORU
UEDA TOORU
MATSUDA JIYUN
NIPPON TELEGRAPH & TELEPHONE