UUCP (UNIX-to-UNIX CoPy) was a queued dialup technology to reliably transfer files between UNIX systems, and optionally execute (uux) a command with the resulting file, first in V7 UNIX in 1978.

UUCP was mainly used to send e-mail.

An address ucbvax!mark (or ucbvax^mark) sent a message to UUCP host ucbvax (U.C. Berkeley’s VAX,) user mark.

If ucbvax wasn’t directly connected to the sending host, the sender could manually route the message, e.g. duke!research!ucbvax!mark sent the message to Duke University, then to Bell Labs Research in New Jersey, then to ucbvax.

Since all mail had to be routed, your e-mail address depended on where the sender was.  End users had to know how to route e-mail.

E-mail addresses like research!greg@Berkeley were ambiguous, which presented a special challenge to users and mail software.  Should the message be sent first to Berkeley and then to research, or first to research and then to Berkeley?  Depending upon the context, either interpretation might be the one that would work.

With no registrar, duplicate names were common.

Several Netizens proposed to create a map of UUCP, asking everyone to send their UUCP connectivity. Each was buried under a huge pile of data and gave up.

The UUCP email message below was sent by Tim Thompson (stargate!starcube!tgt) to Mark Horton, Kurt Shoens (author of the “mailx” command, originally “Mail”) and Tom Truscott (a Usenet founder.)   The mailx “reply” command had to untangle the email addresses in the To and Cc lines, and the multiple “From” lines at the top, to get the reply to all the right people.

From uucp Sat Apr 16 22:40 EST 1981

>From tgt  Sat Apr 16 22:40:30 1981 remote from starcube

To: stargate!mark

Cc: stargate!ucbvax!kurt, stargate!research!duke!trt

Subject: Systems entries for stargate

Date: 16 Apr 81 23:38:06 EDT (Sat)

From: starcube!tgt (Admin)

Mark,

   The following two entries seem to work the best for connecting to stargate

at both 2400 and 1200. I've tested both of them, and they work fine.

   I have yet to play with the Telebit. I'll probably do so either Sunday

afternoon or during the week.

                                       Tim

Continue to Usenet, 1979