p_l parent
UUCP was Unix only, and was only getting started around that time with more copies of Unix showing up outside of Bell Labs
Thank you. I wonder: is FTP that old? I kind of thought UUCP predated FTP. My parent mentioned email possibly being a special mode of FTP.
_some poking around in Wikipedia_
Indeed, FTP is from 1971 and UUCP is from 1979. And the SMTP page describes that it all started as a mode in FTP.
SMTP evolved as replacement for older approaches which, at one point, involved using FTP to mangle mailboxes remotely. Not so much a special mode for FTP as essentially an "use of" FTP. Similar to how non-trivial amounts of Electronic Data Interchange in business happens over FTP(S) to this day.
UUCP was definitely not "Unix only", several operating systems supported it back in the day, Lisp Machines and ITS could access UUCP over Chaosnet. Mark Plotnick wrote the service (aka deamon) for Chaosnet for Unix in 1984.
For anyone who might not know, UUCP literally stands for "UNIX-to-UNIX copy".
Of course, especially given its relative simplicity, at some point non-UNIX systems started to implement it (I think I maybe used some DOS package at some point).