System and method that prevent messages transferred among networked data processing systems from becoming out of sequence

A data processing system connected to a network, comprising:

• a receiving section receiving messages and other information from other data processing systems in the network, the messages including processing messages about programs to be executed by the data processing system;
• a sending section sending messages to other data processing systems in the network, the messages including processing messages about programs to be executed by the other data processing systems;
• an operation mode setting section setting a mode of the data processing system to “an operation mode” for providing a sequencer message for each of the messages to be transferred on the network, or to “a standby mode” for not providing the sequencer message, one of the data processing systems in the network being allowed to be in the operation mode and others of the data processing systems being in the standby mode;
• an operation declaration section sending to other data processing systems a declaration message saying that the data processing system is ready to be in the operation mode when the receiving section fails to receive the sequencer message for the received messages, when the receiving section receives a declaration message from another one of the data processing systems, the data processing system being in the standby mode;
• a count section counting the number of times that said operation mode declaration section declares, in a specified timing, that the data processing system is ready to be in the operation mode, the data processing system entering the operation mode as a new sequencer when the number of declarations reaches a specified count;
• a message management section managing the processing messages received from the other data processing systems;
• a sequencer selection section for selecting sequencer messages sent from a sequencer in a group to which the data processing system belongs out of sequencer messages sent from sequencers not in the group;
• and
• a declaration invalidation section for informing another data processing system that sent out a declaration message that the declaration message is invalid, if the data processing system was already first to enter the operation mode as the new sequencer.