Abstract: In the disclosed system, the operation of a target computer is monitored by a terminal controller connected to one or more of the computer's input/output ports. The controller can send data on one of the computer's ports and simultaneously record and monitor computer response at several of the computer's input/output ports. Two data queues are provided for each monitored port and received data is stored in a first queue, referred to as a spooler queue, and may be searched for a specified character string before it is transferred to the second queue called the demux queue. Received information, in addition to being searched for a specified character string, is also examined for message type and a message type designation is added to each data word or message transferred to the demux queue. From the demux queue the data is transferred to different storage files depending upon the message type designation.