Interface Message Processors for the ARPA Computer Network
A 1974 technical report from the Defense Technical Information Center, written by Frank E. Heart and Bolt Beranek and Newman of Cambridge, Massachusetts, on interface message processors for the ARPA computer network, aimed at engineers and defence researchers. The single picture is a pair of schematic cabinet diagrams labelled ELECTRONICS and FANS, with thick arrows tracing airflow through the case, which a designer could use as a plain, diagrammatic figure for cooling or equipment layout.
