LO: The First ARPANET Host-to-Host Message
On October 29, 1969, a team at UCLA attempted to log in to a computer at the Stanford Research Institute through ARPANET.
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A Connection Between Computers
On October 29, 1969, a team at UCLA attempted to log in to a computer at the Stanford Research Institute through ARPANET.
The Intended Word
The planned transmission was LOGIN. The connection failed after the first two letters, leaving LO as the memorable first fragment.
A Logbook Survives
Leonard Kleinrock’s account reproduces the IMP log documenting the event at 10:30 p.m. A working record provides a rare tangible trace of a foundational networking experiment.
Not the World Wide Web
ARPANET preceded the Web by decades. A browser window, website or modern Wi-Fi symbol would misrepresent the system being tested.
A Beginning With a Failure
The interrupted message illustrates experimental development rather than a flawless launch. The milestone was communication between networked hosts, not the completion of the modern internet in one night.
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