On a coop term I wrote some kind of data collection program for Dept of Fisheries and Oceans in Fortran77, and people in the field would upload their data via the acoustic coupler.
If I recall correctly my application worked at 110 bytes/sec
You read that correctly.
I don't think BSD was even a twinkle in anyone's eye in about .. 1981... we would have been using a minicomputer like VAX? Maybe Prime? Possibly HP... I'm guessing Prime, with their own proprietary OS. I doubt very much anyone had considered "security".
What a time to be alive :-)
Actually, that was 110 bits per second, or 10 characters per second. A character transmission consisted of one start bit, eight data bits, and two stop bits. This allowed for an arbitrary time between characters, which was necessary because a character was transmitted when the operator pressed a key.
The next step up from acoustic coupling was the 300 bits per second modem.
I can't speak for HP or Prime, but those of us who worked on the DEC VAX were very concerned about security. We split the usual user mode versus supervisor mode into four parts so that RMS, for example, could be isolated from the user's application but the kernel remained isolated from both.