It was 40 years ago today ... "Lo!"

by Detlef Borchers

The internet has many fathers and numerous birthdays to celebrate, as the many "children" together constitute the internet in its present form. Today is one of these birthdays: The first message between two remote host computers was exchanged 40 years ago.

Leonard Kleinrock in front of an IMP
Source: Wikimedia Commons On the 29th of October 1969, the first message was sent across the ARPANET, a network that preceded the internet. Leonard Kleinrock and his programmer Charlie Kline tried to log into a computer at the Stanford Research Institute (SRI) from their computer at the University of California (UCLA). The most important component involved was what they called the IMP, the Interface Message Processor, a data communications computer that controlled the exchange of data within the packet-switched ARPANET.

In January 1969 the ARPA military research agency contracted a company called Bolt Beranek and Newman (BBN) to build 16 IMPs. The idea was to structure a packet-based digital communications network in a way that allowed "blocks of information" to be redirected as required in case of a network disruption. This idea was developed and conceptualised for ARPA by Paul Baran in a study comprising eleven volumes in 1964.

However, the proof of any theoretical pudding is in practical testing. Leonard Kleinrock described the proceedings in his memoirs. On the 2nd of September, BBN delivered the first IMP built by Honeywell according to BBN's specifications. At UCLA, Steve Crocker and John Postel successfully connected it to a computer made by Scientific Data Systems. The second IMP followed in October and was installed at Stanford. On the 29th of October, the researchers started the connection experiment, which Kleinrock remembered in 2006 as follows:

The procedure was to type "log" and the system at SRI was set up to be clever enough to fill out the rest of the command, namely to add "in", thus creating the word "login". A telephone headset was available to the programmers at both ends so they could communicate by voice as the message was transmitted. At the UCLA end, we typed in the "l" and Charlie asked SRI if they received it; "got the l" came the voice reply. UCLA typed in the "o", asked if they got it; back came the reply "got the o". UCLA then typed in the "g" and the darned system CRASHED! It was not the IMPs that crashed, it was not the long-haul line that crashed, it was not our UCLA Host that crashed; it was the SRI Host. Quite a beginning. And so the very first message ever sent over the Internet was "Lo!" as in "Lo and behold!" Quite a prophetic message indeed.

What may seem like a false start turned out to be a phenomenally successful test run in 1969: On that same first day, a stable connection was established that, according to test report number 1928, was up for a total of 27 hours and produced a single faulty packet during the transmission of 20,000 sent and received data packets. At a calculated maximum rate of 50 Kbits/s using 19 simultaneous telephone lines, the IMP-controlled network was also the fastest network of its time – it successfully handled the data throughput of 700,000 bits per second that had been stipulated by ARPA.

It was a small step for computer networking, but a giant step towards the digital lifestyle that has become a reality today. Even if the technological pioneers have kept to old traditions and are still arguing about who is the real father of the internet and who first had the packet idea, we have a genuine reason to celebrate today. If you don't want to toast to a machine, you could celebrate the memory of Jon Postel, who was among those who refused the title "father of the internet".

(djwm)