The first UCLA–SRI message passed on October 29, 1969. The log and early maps survive, along with equipment photographed decades later. Each caption separates the date of the object or document from the date of its photograph.
Topic: ARPANET and early computer networking
01 / 06
The machine between the hosts
The front panel of UCLA’s original Interface Message Processor, photographed at the restored Boelter Hall laboratory in 2011. Built by BBN, the IMP handled the network connection between a local host computer and other sites. This photograph records preserved equipment, not the October 1969 experiment as it happened.
Andrew “FastLizard4” Adams / Wikimedia Commons; CC BY-SA 3.0.
02 / 06
UCLA’s side of the connection
Part of the preserved SDS Sigma 7 installation at UCLA, including a tape unit. The Sigma 7 was the host from which Charley Kline attempted the remote login to SRI. The hardware survives in the restored laboratory; the camera date is October 2011.
Photo details
Date
October 29, 2011; equipment from the original laboratory
Andrew “FastLizard4” Adams / Wikimedia Commons; CC BY-SA 2.0.
03 / 06
The entry at 22:30
The IMP log records a host-to-host exchange with SRI at 22:30 on October 29, 1969. Charley Kline’s initials appear beside the entry. This 2011 photograph shows the original record; accounts of the interrupted LOGIN sequence come from the people involved.
Photo details
Date
Log entry: October 29, 1969; photograph: October 29, 2011
Andrew “FastLizard4” Adams / Wikimedia Commons; CC BY-SA 2.0.
04 / 06
Four sites by December
The handwritten December 1969 sketch joins UCLA, SRI, UC Santa Barbara and the University of Utah. The boxes beside the nodes identify host computers. It records a small network of research institutions, two months after the first UCLA–SRI exchange.
Photo details
Date
December 1969
Location
United States
Photographer
DARPA
Archive / collection
Wikimedia Commons / documented source collection
Rights / license
Public domain in the United States; U.S. federal government work.
This early logical map shows a network larger than the original four sites. The map itself is labeled April 1971; the Commons catalog also carries a June 7, 1971 date. Its lines represent network connections, not the physical routes of every cable.
Photo details
Date
Network map: April 1971; catalog date: June 7, 1971
An Interface Message Processor preserved at the Computer History Museum. The large cabinet makes an easily forgotten point: connecting computers originally required substantial dedicated hardware. This is a later museum photograph, rather than an image of the first transmission.
Photo details
Date
Modern museum photograph; catalog lists 2007, embedded image date 2010
