REDIRECT BIOS output to serial __ios

REDIRECT BIOS output to serial port

This article turns from: http://blog.chinaunix.net/uid-7210505-id-173764.html

1 redirect the BIOS output to the serial port

This feature requires major support, please refer to the motherboard user manual.

2 redirect Grub output to serial port

Edit Grub's configuration file/boot/grub/menu.lst and add the following line:

Serial--unit=0--speed=9600--word=8--parity=no--stop=1
Terminal--timeout=10 Serial Console

During the grub boot process, output is sent to both the terminal screen and the serial port. The grub boot process will prompt the press any key to continue on the terminal and the HyperTerminal connected to the serial port, every second prompts once, a total of 10 times, can modify Menu.lst file terminal line--timeout=10 change the number of prompts, During this time, the keyboard can be in the terminal, alternatively, connect to a serial HyperTerminal and press any key to enter the Grub menu. If you do not press any key on the terminal and the HyperTerminal connected serial port in 10 seconds, the Grub selection menu will appear on the HyperTerminal connected to the serial port, if you want to by default The Grub Selection menu appears on the terminal, you can modify menu.lst to modify the serial console to console serial.

3 output kernel output to the serial port

Modify the kernel line to increase the increase after the line

CONSOLE=TTYS0,9600N8 console=tty0

Then the kernel outputs the output information to the serial port and terminal. The records I have modified in my menu.list are as follows:

Title Debian Gnu/linux, kernel 2.6.8-2-386
Root (hd0,0)
kernel/vmlinuz-2.6.8-2-386 root=/dev/mapper/rootvg-root ro console=ttys0,9600n8 console=tty0
Initrd/initrd.img-2.6.8-2-386
Savedefault
Boot

In the example above, service startup information will be displayed on the terminal (TTY0), if entered Single-user mode, will only be prompted in the terminal (TTY0) to enter the root password, if you need the service to start the information also output to the serial port, you can modify the order of two console parameters, both revised to

Console=tty0 CONSOLE=TTYS0,9600N8

4 Allow access to Linux from the serial port

Modify the/etc/inittab file to add the following

T0:23:respawn:/sbin/getty-l ttyS0 9600 vt100

will be enabled to log on to Linux from the serial port when it is completed.