When did ARAPNET go online?

Answer 1

The answer to this one is kind of hard. ARAPNET started as 2 computers one at UCLA and the other at Stanford, this was established in 1969. Then the commonly accepted 4 computer network that added UC Santa Barbara and University of Utah was established in December of 1969. December of 1971 spread the network accross 23 host computers. So those are your answers: 2 computers in 1969, 4 computers in December of 1969, or a 23 computer network in 1971. "The final requirement was to design a protocol to allow the computers to send and receive messages and data, known as an interface message processor (IMPs). Work on this was completed in 1968, and the time was ready to put the theory to the test. In October 1969, IMPs installed in computers at both UCLA and Stanford. UCLA students would 'login' to Stanford's computer, access its databases and try to send data. The experiment was successful and the fledgling network had come into being. By December 1969 APRANET comprised four host computers as with the addition of research centres in Santa Barbara and Utah. In the months that followed, scientists worked on refining the software that would expand the network's capabilities. At the same time, ever more computers were linked to the net. By December 1971 ARPANET linked 23 host computers to each other." Source: http://www.let.leidenuniv.nl/history/ivh/chap2.htm#The%20Creation%20of%20ARPANET