Normally there's an Adafruit Feather M4 Express with some weather sensors connected to one of the machines. While I did write a simple serial terminal in Go for displaying the output, something had gone wrong and the program was no longer working the last time I tested it under Void Linux, so I switched to Picocom. There is also an issue where the Feather will stop updating and the terminal will freeze with some errors about the device not being a tty...
Switching to NetBSD on the RPi Zero W was annoying because the documentation is not very good for some topics, particularly external storage and serial device communication. It took a while to figure out which of the _many_ tty devices in /dev were actual devices and not just placeholders, but eventually I was able to connect the Feather to the Pi, though this required root privilages to read from /dev/ttyU0. It also had the same issue of freezing up with a similar message that the device is not a tty...
So when OpenBSD was installed on _all the machines_, it seemed logical to install Picocom and get some weather data from the Feather, except that there's already a serial terminal emulator on OpenBSD, called 'cu'. It's a rewrite of a "call unix" tool that first appeared in PWB/UNIX 1.0, according to the man page. It also happens that I _don't_ need root privilages to read from dialout devices, which is exactly what the Feather is. Either I missed this on NetBSD or the man pages on OpenBSD were more clear on this point. Either way, it was nice to _not_ install another tool.
First I run dmesg to find out which ucom device is associated with the Feather. It shows 'ucom1 at umodem1', so then I run 'cu -dr -l cuaU1 -s 115200'. Within seconds, the sensor data shows up on the terminal, and I didn't even have to use doas(1), su(1) or even sudo (which isn't installed). Awesome!
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