The First Email Computer

The inaugural email was transmitted between the two machines depicted in this photograph, which were positioned side by side, with their only link being the ARPANET. In the foreground is BBN-TENEXA (commonly referred to as BBNA), the machine that received the first email. At that time, in 1971, host names did not include extensions like .com; the Domain Name System (DNS) was introduced later. In the background is BBN-TENEXB (known as BBNB), the machine from which the first email was sent. Visible in the left foreground is the Teletype KSR-33 terminal that printed the initial email. Just behind it, though largely obscured, is another KSR-33 where the first email was typed.

BBNA was a Digital Equipment Corporation KA10 (PDP-10) equipped with 64K (36-bit) words of real magnetic core memory, which is equivalent to 288 KBytes by today’s standards. In contrast, BBNB was smaller, featuring only 48K words of memory. Both machines operated using the TENEX time-sharing monitor.