DescriptionTimesharing and Development KA-10s at BBN, circa 1970.jpg
English: Timesharing and Development KA-10s at BBN, circa 1970. According to Ray Tomlinson: "The first email was sent between the two machines shown in this photograph. They were (obviously) side-by-side, but the only connection between them was through the ARPANET. In the foreground is BBN-TENEXA (BBNA for short). Host names in 1971 had no .com or dot anything; DNS came along later. BBNA was the machine on which the first email was received. In the background is BBN-TENEXB (BBNB) from which the first email was sent. On the left, foreground, is the Teletype KSR-33 terminal on which the first email was printed. Immediately behind and largely obscured is another KSR-33 on which the first email was typed. BBNA was a Digital Equipment Corporation KA10 (PDP-10) with 64K (36-bit) words of (real magnetic) core memory. In modern measure, that's 288 KBytes. BBNB was smaller with only 48K words. Both machines ran the TENEX time-sharing monitor."
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.