The low level details of the Linux TTY driver is a surprisingly deep subject. This very old page taught me a lot about it and a recent HN discussion reminded me to dig up the old link. Hopefully others find it as enlightening as I have.
Frankly, the way the functionality needed to implement LF-to-CRLF conversion on output/CR-to-LF conversion on input/line editing/session and process management is split between the terminal itself, the kernel, and the application code is quite awkward.
And of course, the concerns of the serial line driver are thrown into the mix too, for the added entertainment.
This article caught my eye since I've been playing with kmscon. Learned quite a bit, thanks. Though feel I'm still a bit unclear on how systemd init starts the agettys and that area. Also newer distro versions appear to have moved graphics from vt7 to vt1. Not sure of the reasoning why.
What I'd like to do is keep the boot log at tty1 and not wipe it out when finished.
N_DEVELOPMENT is a line discipline number for testing, first supported in Linux v5.18-rc1 from 2022, so you don't have to overload an actual discipline like SLIP or PPP when hacking.
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[ 15.9 ms ] story [ 323 ms ] threadAnd of course, the concerns of the serial line driver are thrown into the mix too, for the added entertainment.
What I'd like to do is keep the boot log at tty1 and not wipe it out when finished.
This answer seems like it might help, going to try it. https://askubuntu.com/a/195926/116108