by summers » Wed Oct 17, 2018 9:46 am
Probably much of the reason you get messages after the login prompt, is that arch uses systemd to start up the system. This means it starts up init processing in parallel, but taking care of dependencies between different processes.
E.g. a login process only makes sense when the home file system is mounted.
Now when all dependencies for the the login are met, systemd will start the login process (actaully start up getty), and you can log in. However not everything will be up by then. e.g. the ethernet may not have yet come up, however this doesn't stop you logging in. but when the ethernet comes up the console will get a message.
Now this brings in the console, that is where all info is sent. Now on SBC this is typically a UART coming straight off the cpu, so at whatever voltages it can do, usually 3.3V. Having raw messages on the console is good, it means when the machine isn't working, or booting, or whatever - you can always attach to the uart to check the error. The same is true on desk tops, where the console is usually one of the virtual terminals behind the graphical log in.
So this brings up another question, why do usual logins on the console? I usually just use the console for debugging. There are some machines I have where i have never attached a connection to the uart - havn't got round to soldering on a header ...
So guess this is a question in your direction - guess you are doing standard logins on the console? Why is this? Have you set up the console pointing to the wrong place? Or is there a reason for only doing low level input? As theSaint says, if you log in on the ethernet, you probably wouldn't see all these messages ...