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Vint Cerf Remembers Ray Tomlinson

Ray Tomlinson

By Hatti Hamlin

While Marconi Vice-chair Cerf worked in California on the early implementation of TCP, Ray Tomlinson did related worked at BBN in Massachusetts, Tomlinson, who died at 74, wrote one of the first implementations of TCP. He’s best known for developing the “@” sign for the first electronic mail over the Internet. Cerf notes billions have benefited from Tomlinsos seminal work on networked electronic mail,

The “@” separated people’s system name from the Arpanet system they were working at. That allowed simple email addressing and solved the problem of people on different systems with the same identifier. The Museum of Modern Art has included the sign in its Design Collection,

Vint just wrote this memorial:

I knew and worked with Ray Tomlinson during the development of the ARPANET and its host protocols and benefited, as have billions, from his seminal work on networked electronic email. More important, from my personal perspective, was his work with Bill Plummer on the first PDP-10 TENEX implementation of TCP (and later TCP/IP). In 1975, he discovered that the TCP as specified in December 1974 had flaws that led it to fail to detect duplicate packets and, together with Yogen Dalal, developed the three-way handshake and initial sequence number selection method to solve this problem. As Craig Partridge summarizes, Ray was a long-time and creative contributor to the Internet, operating systems, and many other highly practical applications in the computer science and communications domains. He was a self-effacing and humble man and extraordinary performer in our online world. I will miss his thoughtful, low-key and always helpful counsel.

Craig Partridge worked with Tomlinson at BBN, He writes:

Ray Tomlinson had been at BBN since 1967. He’s best known for inventing the concept of sending email over a computer network and choosing the @ sign as the way to split the mailbox name from the host name. But that’s a fraction of his amazing contributions to our field. Ray was one of a four person team that created TENEX, the first operating system to support virtual memory using paging. He wrote one of the first implementations of TCP and, when he found data being duplicated in the received stream, devised methods to ensure that sequence numbers were not duplicated that remain fundamental to TCP/IP implementations today. He worked on the first object-oriented distributed system and early multimedia email systems. And I’m sure I’m forgetting at least half a dozen other ways Ray made our world better.

These messages were forwarded to Dave Farber’s Interesting People list by Jari Arkko of the IETF.