PURPOSE: To efficiently provide an integrated and high-grade operation support function in a data processing system which is connected to plural computers via a network.

CONSTITUTION: An optional numbers of operation support server 1 including a rule file 2 which stores the roles to control execution of an operation support function according to the purpose of a user and a dictionary file 3 which stores various information necessary for execution of the rules are provided on an optional computer in a network. Thus, each server 1 has communication with its corresponding program with transfer of a message based on an inferring function using those rules and the dictionary data. In such a constitution, the operation support functions of programs working in a data processing system are integratedly carried out.