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Ray Tomlinson

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Ray Tomlinson was an American computer programmer who changed how the world communicates. He is best known for inventing the first email program on the ARPANET system in 1971. ARPANET was the early precursor to the modern Internet. Before Tomlinson's work, digital mail was very limited. People could only send messages to others using the exact same computer. Tomlinson's invention allowed users to send messages between different hosts on a network. This breakthrough turned a simple messaging tool into a global communication system.

To create this system, Tomlinson had to solve a specific technical problem. He needed a way to tell the computer which person to message and which machine to send it to. He decided to adapt an existing program called SNDMSG. This program previously only worked for users on a single time-sharing computer. Tomlinson incorporated source code from another program called CPYNET. CPYNET was a file transfer program designed for the ARPANET. By combining these tools, he enabled messages to travel across the network to different computers.

A vital part of this process was the creation of the email address format. Tomlinson needed a symbol to separate the username from the name of the machine. He chose the @ symbol for this task. He selected it because it was not used in usernames or in TENEX programming. The symbol also intuitively conveyed the intended meaning of the recipient's location. This created the user@host format. This specific scheme has remained the standard for email addresses for over fifty years. The @ sign is now considered a defining symbol of the computer age.

Tomlinson's journey into computing began during his time as a student. He earned a bachelor's degree in electrical engineering from Rensselaer Polytechnic Institute in 1963. He later attended the Massachusetts Institute of Technology (MIT) for graduate studies. At MIT, he focused on speech synthesis, which is the process of making computers produce human-like speech. He became fascinated by computers after seeing students play a video game called Spacewar!. This interest led him to develop an analog–digital hybrid speech synthesizer for his master's thesis. He received his master's degree in 1965.

In 1967, Tomlinson joined the technology company Bolt, Beranek and Newman, also known as BBN. He worked there for the rest of his career as a principal scientist. While at BBN, he helped develop the TENEX operating system. He also worked on the ARPANET Network Control Program and several other important programs. One of his notable technical contributions was the invention of the TCP three-way handshake. This is a process used by the Transmission Control Protocol (TCP). TCP underlies HTTP and many other essential Internet protocols used today.

Tomlinson's first successful email was actually a simple test. He sent the message between two computers that were placed right next to each other. He did not preserve the content of the message. He later described the text as insignificant and forgettable. It was likely just a random string of characters, such as "QWERTYUIOP." Although the message itself was not important, the successful transmission proved the system worked. This small test led to a revolution in how humans share information.

Many honors have been given to Tomlinson for his scientific achievements. He was inducted into the Internet Hall of Fame in 2012. In 1992, an asteroid named 10108 Tomlinson was discovered in his honor. Every year on April 23, people celebrate Email Day. This date was chosen because it is Tomlinson's birthday. He received many other awards, including the IEEE Internet Award and the Prince of Asturias Award. Even though he was a pioneer of digital life, he was a self-professed Luddite. He lived a quiet life in Lincoln, Massachusetts, until he died of a heart attack in 2016 at age 74.

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