Computer system and data transmission / receiving start process

A computer system and monitoring method for efficiently monitoring a plurality of computers interconnected within a network. In this computer network system, each computer has a self-monitoring unit for monitoring its own computer and acquiring a monitor message, and a transmitting unit for transmitting the monitor message to a monitoring computer. Monitor messages transmitted from a plurality of computers are received by the monitoring computer. The monitoring computer has a receiving unit for receiving monitor messages, and a displaying unit for outputting monitor messages to a display. The receiving unit, displaying unit, and display windows on the display are provided for each of a plurality of computers to be monitored.