Abstract: A data communication system includes in middleware a transmission task that transmits a message to a receiving host computer through a network, considering the transmission capability of the transmitting host computer and the receiving capability of the receiving host computer. This solves the problem in a conventional data communication system in which, if a host computer loses a token after acquiring it, operator stations and the like connected to a network are unable to send a message.

Abstract: An interactive graphic recognition and data processing system includes an image reader for reading a facility drawing in which facility symbols are drawn, a display device for displaying the facility drawing read by the image reader overlapped with a topographical drawing corresponding thereto, a mouse for designating the position of the facility symbol displayed on the display device, a recognition device for recognizing the facility symbol designated by the mouse by comparing the same with a plurality kinds of facility symbols previously stored and causing the facility symbols recognized thereby to be displayed in different color from the color of the facility symbols which have not yet been recognized, and a memory for storing therein positional data in the topographical drawing of the facility symbol recognized by the recognition device and attributive data about the facility symbol as data base.