Unsung innovators: Ray Tomlinson, who put the @ sign in every e-mail address

In the early 1970s, Ray Tomlinson worked out one of the earliest e-mail systems. That's cool, but here's something more intriguing. He is actually the guy responsible for the "At" sign (@) in every e-mail address today.

Tomlinson, a shy sort, says he is just fine with his name not being a household name. "In fact, I'm pretty happy being unsung."

Tomlinson today is a principal engineer at the Cambridge, Mass.-based BBN Technologies. But he was just starting out at the company when he came up with the e-mail system and address notation. Just 29 years old and a junior employee then, Tomlinson says he was supposed to be doing something else and at the time wasn't sure whether he should share what he came up with.

In retrospect, he's glad he did.

"You see, I wanted to build the first e-mail system to allow messages to be sent from one person" on one computer over a network to someone who was using an entirely different computer, Tomlinson says. He points out that, at the time, e-mail was possible only between people using terminals connected to the same computer.

"I was trying to denote on which computer a user had his mailbox because his username would already be unique on that computer," he explains. In other words, he needed a username structure that had to be unique across all computers.

Ray Tomlinson

Ray TomlinsonTomlinson downplays his offering to the history of IT. "The thought process was not very complicated," he says. "I [needed] a character on the keyboard that did not normally appear in the log-in names of users or in the host name of computers." This ruled out letters, numerals and many punctuation characters, including commas, periods, colons, semicolons, square brackets, angle brackets and parentheses.

But it did leave "several" punctuation marks, he says.

So how did the "At" symbol win its place in e-mail history? "Of all the available punctuation marks, only the "At" sign had a sense of place," he says. "I could have used the "On" sign or the "Of" sign, but there are no such characters. So the at-sign had to be it."

Tomlinson, a native of New York state, is in his 40th year working @ BBN.

Copyright © 2007 IDG Communications, Inc.

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