Provided is an operating method of a system including a first data processing module, a second data processing module, and one or more data connection modules that transfer data between the first data processing module and the second data processing module. In an operational state where the first data processing module and the second data processing module can process data input thereto, the first data processing module inputs trigger data to any of the one or more data connection modules, and in response to the second data processing module receiving the trigger data via the one or more data connection modules, the second data processing module changes a reading rule for reading data from the one or more data connection modules. Also provided are a system and a computer program product.