Editing ARPANET (section)

=== Initial four hosts ===
[[File:First-arpanet-imp-log.jpg|thumb|upright=1.35|First ARPANET IMP log: the first message ever sent via the ARPANET, 10:30&nbsp;pm PST on 29 October 1969 (6:30 UTC on 30 October 1969). This IMP Log excerpt, kept at UCLA, describes setting up a message transmission from the UCLA SDS Sigma 7 Host computer to the SRI SDS 940 Host computer]]

The initial ARPANET configuration linked [[UCLA]], [[Augmentation Research Center|ARC]], [[UCSB]], and the [[University of Utah School of Computing]]. The first node was created at UCLA, where [[Leonard Kleinrock]] could evaluate network performance and examine his theories on [[message delay]].<ref>{{cite thesis |author=Kleinrock, Leonard |date=December 1962 |title=Message Delay in Communication Nets with Storage |url=http://dspace.mit.edu/bitstream/handle/1721.1/11562/33840535.pdf |location=Cambridge |publisher=Massachusetts Institute of Technology |type=Thesis}}</ref><ref name=":8">{{Cite thesis |last=Clarke |first=Peter |title=Packet and circuit-switched data networks |date=1982 |degree=PhD |publisher=Department of Electrical Engineering, Imperial College of Science and Technology, University of London |url=https://spiral.imperial.ac.uk/bitstream/10044/1/35864/2/Clarke-PN-1982-PhD-Thesis.pdf |archive-date=3 August 2022 |access-date=12 June 2024 |archive-url=https://web.archive.org/web/20220803035935/https://spiral.imperial.ac.uk/bitstream/10044/1/35864/2/Clarke-PN-1982-PhD-Thesis.pdf |url-status=dead }} "Many of the theoretical studies of the performance and design of the ARPA Network were developments of earlier work by Kleinrock ... Although these works concerned message switching networks, they were the basis for a lot of the ARPA network investigations ... The intention of the work of Kleinrock [in 1961] was to analyse the performance of store and forward networks, using as the primary performance measure the average message delay. ... Kleinrock [in 1970] extended the theoretical approaches of [his 1961 work] to the early ARPA network."</ref><ref>{{Cite journal |last=Lukasik |first=Stephen |date=March 2011 |title=Why the Arpanet Was Built |url=https://ieeexplore.ieee.org/document/5432117 |journal=IEEE Annals of the History of Computing |volume=33 |issue=3 |pages=4–21 |doi=10.1109/MAHC.2010.11 |issn=1058-6180|url-access=subscription }}</ref> The locations were selected not only to reduce leased line costs but also because each had specific expertise beneficial for this initial implementation phase:<ref name="LIARPANETTheFirstInternet"/>

* University of California, Los Angeles (UCLA), where Kleinrock had established a Network Measurement Center (NMC), with an [[Scientific Data Systems|SDS]] [[SDS Sigma series|Sigma 7]] being the first computer attached to it;
* The Augmentation Research Center at Stanford Research Institute (now [[SRI International]]), where [[Douglas Engelbart]] had created the new [[NLS (computer system)|NLS]] system, an early [[hypertext]] system, and would run the [[Network Information Center]] (NIC), with the [[SDS 940]] that ran NLS, named "Genie", being the first host attached;
* [[University of California, Santa Barbara]] (UCSB), with the [[Glen Culler|Culler]]-Fried Interactive Mathematics Center's [[IBM]] [[System 360|360/75]], running [[OS/MVT]] being the machine attached;
* [[File:A sketch of the ARPANET in December 1969.png|thumb|A sketch of the ARPANET in December 1969. The nodes at UCLA and the Stanford Research Institute (SRI) are among those depicted.]]The [[University of Utah School of Computing]], where [[Ivan Sutherland]] had moved, running a [[Digital Equipment Corporation|DEC]] [[PDP-10]] operating on [[TENEX (operating system)|TENEX]].

The first successful host-to-host connection on the ARPANET was made between Stanford Research Institute (SRI) and UCLA, by SRI programmer Bill Duvall and UCLA student programmer Charley Kline, at 10:30&nbsp;pm PST on 29 October 1969 (6:30 UTC on 30 October 1969).<ref>{{cite news |title=Browsing history: A heritage site has been set up in Boelter Hall 3420, the room the first Internet message originated in |url=https://dailybruin.com/2011/04/01/browsing_history/|first=Jessica |last=Savio |newspaper=Daily Bruin |publisher=UCLA |date=1 April 2011 |access-date=6 June 2020}}</ref> Kline connected from UCLA's [[SDS Sigma 7]] Host computer (in Boelter Hall room 3420) to the Stanford Research Institute's [[SDS 940]] Host computer. Kline typed the command "login," but initially the SDS 940 crashed after he typed two characters. About an hour later, after Duvall adjusted parameters on the machine, Kline tried again and successfully logged in. Hence, the first two characters successfully transmitted over the ARPANET were "lo".<ref>{{Cite web|last=McMillan|first=Carolyn|date=2019-10-29|title=Lo and behold: The internet|url=https://www.universityofcalifornia.edu/news/lo-and-behold-internet|access-date=2021-03-02|website=University of California|language=en}}</ref><ref>{{cite web |title=Internet Began 35 Years Ago at UCLA with First Message Ever Sent Between Two Computers |url=http://www.engineer.ucla.edu/stories/2004/Internet35.htm |first=Chris |last=Sutton |publisher=UCLA |date=2 September 2004 |archive-url=https://web.archive.org/web/20080308120314/http://www.engineer.ucla.edu/stories/2004/Internet35.htm |archive-date=8 March 2008 |url-status=dead}}</ref><ref>{{cite web|url=https://computerhistory.org/blog/history-of-the-future-october-29-1969-fifty-years-of-a-connected-world/|title=The First 50 Years Of Living Online: ARPANET and Internet|first=Marc|last=Weber|date=October 25, 2019|work=[[Computer History Museum]] blog}}</ref> The first permanent ARPANET link was established on 21 November 1969, between the IMP at UCLA and the IMP at the Stanford Research Institute. By 5 December 1969, the initial four-node network was established.

[[Elizabeth Feinler]] created the first Resource Handbook for ARPANET in 1969 which led to the development of the ARPANET directory.<ref>{{harvnb|Evans|2018|p=112}}</ref> The directory, built by Feinler and a team made it possible to navigate the ARPANET.<ref>{{harvnb|Evans|2018|p=113}}</ref><ref>{{harvnb|Evans|2018|p=116}}</ref>