| 摘要 |
PURPOSE:To decrease the past state value to be stored in a process by circulating the token ownership among plural processes that proceed their processings with mutual exchange of message and rolling back the ownership to a stage preceding by a single token cycle by detecting a fault in a single token cycle. CONSTITUTION:Each process receives a token T via a control block 100 and decides via a control block 101 whether its own process is equal or not to a process having the next token ownership. If so (YES), it is decided that the abnormality exists. In such a case, a token owner process turns the value of a time stamp into the value older by a single token cycle via a control block 107. Simultaneously, a system state variable is also set its past state to set a roll-back processing request for the request of a retrial. |
