topic Re: Regarding serial console in Operating System - Linux

Regarding serial console

Minoru Asano — Thu, 31 May 2007 04:59:45 GMT

Hello,

[ENVIRONMENT]
HP ProLiant BL20p G3
RHEL 3

[SITUATION]
The customer used serial console.
When he reboot the host, he could use the serial console.
But the serial console has not response while he is using.
After that, he killed tcsh which is TTY is ttyS0 by using "kill -9" command.
So the following message has appeared:

- /var/log/messages -
May 28 14:25:12 host-A init: Id "S0" respawning too fast: disabled for 5 minutes
May 28 14:30:13 host-A init: Id "S0" respawning too fast: disabled for 5 minutes

Now he can not use serial console.
This trouble might solve to restart the host, but he would like to solve this trouble without reboot.

[QUESTION]
- What shall he does to be able to use serial console again ?

Thank you for advice.
Best Regards.
/Minoru.

Re: Regarding serial console

Steven E. Protter — Thu, 31 May 2007 11:13:38 GMT

Shalom,

To properly use a serial console, it will be necessary to take a look at /etc/inittab

The console was set up on /etc/inittab but probably not correctly.

You may wish to post the file to help us figure out the issue.

http://www.vanemery.com/Linux/Serial/serial-console.html

SEP

Re: Regarding serial console

Minoru Asano — Fri, 01 Jun 2007 06:52:02 GMT

Hello,
Thank you for reply.

I got the several information.

- /etc/inittab
S0:12345:respawn:/sbin/mingetty ttyS0

- /etc/grub.conf
serial --unit=0 --port=0x03F8 --speed=115200 --word=8 --parity=no --stop=1 terminal --timeout=10 serial console

- ls -l /dev/ttyS0
crw------- 1 root root 4, 64 May 29 15:16 /dev/ttyS0

- There was not "/sbin/mingetty ttyS0" process.

If you get any information, please let me konw.

Is there any method to be able to use serial console again without rebooting system ?

According to the customer, he has tried to execute "init q" command. But he still can not use serial console.

Thank you for advice.
Best Regards.
/Minoru.

Re: Regarding serial console

Hemmetter — Fri, 01 Jun 2007 07:06:50 GMT

Hi Minoru

from mingetty(8)
DESCRIPTION
mingetty is a minimal getty for use on virtual consoles. Unlike agetty(8), mingetty is not suitable for serial lines.

i think you schould try agetty(8) or mgetty(8)

inittab-entry:

S0:12345:respawn:/sbin/agetty -L 115200 ttyS0

rgds
HGH