Tomlinson, who had earlier implemented Transmission-Control Protocol (TCP) on TENEX, a PDP-10 operating system, decided to create an e-mail system. The idea of sending messages to someone on the same computer dates back to the 1960s. Tomlinson decided that there must be an easy way to send messages between users on different computers.
He built the first e-mail system using his earlier invention, CPYNET, an early file transfer protocol program. He called that first e-mail program: SNDMSG.
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