Answer Geek: Where It's @ in E-Mail

<br> -- Q U E S T I O N: Who picked the @ sign to separate e-mail names from domain names and why?

— Sam B.

A N S W E R: Thanks for the question Sam. It’s always nice to take a moment to remember Ray Tomlinson, one of the real unsung heroes of our time. Tomlinson is the computer engineer who not only brought you that ubiquitous symbol of the modern era, the @ sign, but who is also generally considered to be the e-mail inventor.

How does one get to be the inventor of e-mail, you might ask? Let’s go back in time to find out. The year: 1971. The location: Cambridge, Mass., home to Bolt Beranek and Newman, better known as BBN, the company that was hired by the United States Defense Department to build APRANET, the precursor to the Internet.

Computer Time Shares

On that fateful day, Tomlinson was messing around with a little application he had written called SNDMSG which allowed programmers and researchers working on the same machine to leave electronic messages for each other. Remember, this was 1971, before the days of the PC and a computer on every desk, so sharing a computer was pretty much the order of the day.

SNDMSG was a pretty crude piece of work compared to the massive e-mail programs of today. All it did was allow a user to create a text file and drop it in a “mailbox” for someone else on a local machine. The reason it could be labeled a messaging program at all was the fact that users could add material at the end of the file, but they couldn’t read or overwrite the material that was already there.

At the time, one of Tomlinson’s projects was an experimental file transfer protocol called CYPNET, which let researchers transfer files between the 15 computers that made up the ARPENET system. CYPNET worked well enough for that job, but no one had thought to make it possible to append new material to an existing file. That was Tomlinson’s flash of genius. He realized that a few changes to the CYPNET protocol would make it work much like SNDMSG, but with a very useful twist: it would then be possible to send messages to researchers working on computers at other locations on ARPENET.