In the mid 1960s, the U.S. Department of Defense Advanced Research Projects Agency (ARPA) began work on the network that ultimately grew into the Internet as we know it today. The very first stage of the ARPAnet connected mainframes at just four locations over blazingly fast (for the time) 56 Kbps leased telephone lines. Larry Green was one of the engineers involved in this development at the University of California Santa Barbara (UCSB).

Larry Green is a technologist with a long track record of founding successful computing enterprises: Communication Machinery Corporation, Efficient Networks, Wavefront Technologies, Web Power Authority, and Protocol Engines. But Larry is also an Internet pioneer, designing and deploying the Internet Message Processor (IMP) on the first node of the Internet at UCSB. While listening to this interview, be sure to browse the pictures and diagrams that Larry references as he describes those heady days of inventiveness.

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Click on any of the images below for a larger image.

Larry explains the S/360 IMP interface	"So the IMP says 'There's your IMP bit'..."
Detailed documentation for the IMP survives	ARPA Report #1822: The IMP Manual
1200 pound IMP with convenient lift rings	IMP mainframe interface protocol diagram
A detail of the UCLA IMP log book, showing the successful connection to SRI.	4-node ARPANET diagram.
ARPANET Map, 1973.	ARPANET Map, 1975.