In this blog, it gives a Recommended serial kernel parameters, PCs with video card.
console=tty0 console=ttyS0,9600n8
It says Kernel messages will appear on both the first virtual terminal and the serial port. Messages from the init system and the system logger will appear only on the first serial port.
As it says before When multiple consoles are listed output is sent to all consoles and input is taken from the last listed console
, Isn't this contradictory? What is the difference between "Kernel messages" and "Messages from the init system and the system logger" ?
I want to know:
- Why is this ? Update: Why do not get the same output between multiple terminals ?
- Where
Messages from the init system and the system logger
go ? - What kind of devices are virtual consoles such as ttyx redirected to, and why I can only see them in the graphical interface of qemu, like
Debian GNU/Linux 10 mindebian tty1
?
Update: In normal we will get message from kernel and rootfs, message from kernel start with a timestamp kernel message, message from init/rootfs start with a OK rootfs message. When I use this boot arguments in the blog, exactly as it described: I will only get kernel message from qemu graphic window.