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Friday, March 22, 2019

The symbol used in every email


©Mark Ollig

He invented the “@” sign we use to connect an email name with the computer host destination address.

Sending emails is such an everyday part of our lives; we don’t think much about it.

Every year, 74 trillion business and consumer emails are sent.

The name of the person we need to thank for today’s email is Raymond S. Tomlinson.

In 1971, Tomlinson was working with the DEC (Digital Equipment Corporation) KA10 PDP-10 computer program called TENEX, a time-sharing software program system operating on Digital PDP-10 computers.

Researching today’s column topic, I looked up the definition for “electronic mail” and was referenced back to the 1840s and inventor Samuel Morse’s use of his Morse Code – which technically was how mail messages were first sent or “keyed” by electronically coded means.

During the 1930s, messages were typed and received on teleprinter terminal machines electronically linked with each other over a shared network.

These machines were used mostly by governments, corporations, newspapers and the military.

The terminal’s message output was printed on paper. The early teleprinter looked a lot like a typewriter.

Telephone companies provided access to the Telex network (mostly via copper cable pairs) for the inter-connection of teleprinter machines. When I started in the telephone industry, we called the teleprinter connection a TWX (Teletype Wide-area eXchange) line.

I recall installing and maintaining TWX (pronounced “Twix”) lines for teletype terminals connected at the local police station, and the larger industries and businesses within the local telephone company serving area.

In the late 1960s, the US Defense Department began working on its own computer network called Advanced Research Projects Agency Network or ARPANET, which evolved into the internet.

Getting back to 1971, 30-year-old Ray S. Tomlinson began working on improving mail messages using a software program called SNDMSG, which his company used within their local network.

At this time, a user’s network mailbox was a simple message text file. User message files could only be sent and accessed over a shared mainframe/host computer network using a teletype machine.

Tomlinson considered the software program called CPYNET, which he realized could be used along with the SNDMSG program to transmit a user’s email or “message-files to other users on different computer networks.

Working with CPYNET software code protocols which transferred files through ARPANET, Mr. Tomlinson was able to incorporate it with the SNDMSG program code used for local inter-user mail.

He programmed these codes so the mail-file messages could determine the local computer host email from email destined to a remote computer host network.

Two host computers operating over separate networks were located in the room Tomlinson was working. The computers sat side-by-side on the same floor.

One computer was a DEC KA10 PDP-10, and the other was a smaller memory capacity model DEC.

Ray Tomlinson decided to use the “@” symbol to identify the terminating email address was “at” a different/remote computer host network; the email addressee was not on the same local computer network as the person originating the email.

By using the @ symbol, Tomlinson was able to use his programming code to connect the user name with the destination address and thus directed an email message to be sent out to a totally separate computer system over the ARPANET and reach its intended email address on the remote host computer.

The first email message was sent in late 1971 from the host computer over the ARPANET and to another computer located on another network.

Tomlinson says the first email message he sent likely contained the test word “QUERTYIOP” or similar. He said in later interviews that he hadn’t kept the original email.

Admittedly, that first e-mail message was historic. We do know the first email was typed on a Teletype KSR-33 terminal connected to one host computer which was successfully sent and received by another host computer’s Teletype KSR-33 on a different network.

"The invention of email came out of a personal desire for a more convenient and functional way to communicate,” Tomlinson said during his induction into the Internet Hall of Fame in 2012.  

“Basically, I was looking for a method that did not require the person to be there when the message was sent and enabled the receiver to read and answer communications at their convenience,” he added.

A photograph of where the first email message using the @ symbol sent between two different host computers over two different networks using Teletype KSR-33 terminals can be seen at https://bit.ly/1QXOhZU.

Tomlinson created the email addressing scheme user@host, which became the standard for email addresses and still is today.

He was a long-time employee of BBN (Bolt, Beranek, and Newman), which, at the end of 1968, won the 1968 US government contract to build the ARPANET, the forerunner of the internet.

Ray Samuel Tomlinson was born in Amsterdam, NY in 1941, and died March 5, 2016, in Lincoln, MA.
Photo created by me! :)