topic Re: Serial Console for I386 Linux in Operating System - Linux

Serial Console for I386 Linux

Volker Borowski — Mon, 05 Nov 2001 14:26:51 GMT

This might be supprising, but ....

I like to have a real serial console for a linux station. Has anyone tried to achive this. I did not even start, and my approach would be to change /dev/console later from /dev/tty1 to /dev/ttyS1 or similar.
(I do not need colors and pc-keyboard, but console access from a console-server).

Does this seem to be a valid approach ?
Something else to think of ? I.E. create special CDs/floppys to boot into single User-Mode with a serial console from CD (i.E. to fix /etc/passwd).

Any comments welcome
Volker

Re: Serial Console for I386 Linux

harry d brown jr — Mon, 05 Nov 2001 16:12:36 GMT

Volker,

http://www.linuxdoc.org/HOWTO/Remote-Serial-Console-HOWTO/

live free or die
harry

Re: Serial Console for I386 Linux

harry d brown jr — Mon, 05 Nov 2001 16:14:44 GMT

Also:

http://www.linuxhq.com/kernel/v2.2/doc/serial-console.txt.html

live free or die
harry

Re: Serial Console for I386 Linux

Volker Borowski — Wed, 07 Nov 2001 16:17:53 GMT

Ok, the HOWTO was a big help.

I have Basics working now, means I get boot messages on a serial console now, but from the point where Linux configures the network it slows down a lot. Just get sporadic messages then allthough complete at the end.
Means: The system is up an fully functional, but it takes almost 10 minutes until the last startup message is completely printed.

I suspect a handshake problem, but did not find anything on how to configure the handshake for the console output. Only speed,parity an stopbits can be set in lilo.conf.

Ideas ?
Volker

Re: Serial Console for I386 Linux

Paulo A G Fessel — Wed, 07 Nov 2001 21:30:43 GMT

Hello, Volker.

To correctly set the options of the serial port on the console, first take a look at /etc/gettydefs. There should be an entry like this:

# 9600 baud Dumb Terminal entry
DT9600# B9600 CS8 CLOCAL # B9600 SANE -ISTRIP CLOCAL #@S login: #DT9600

Next, vi /etc/inittab and add the following line (I'm assuming you're using ttyS1):

S1:2345:respawn:/sbin/getty ttyS1 DT9600 vt100

That is, you'll be running getty listening on ttyS1, with the DT9600 speed (a dumb terminal at 9600) using the vt100 line protocol.

Please try doing this and let me know whether it works.

Paulo Fessel

Re: Serial Console for I386 Linux

Volker Borowski — Thu, 08 Nov 2001 09:50:25 GMT

Hi,

one step further:
- seems like kudzu and gpm send various stuff at the serial port while the bott messages are to be written.
- diabled kudzu and gpm and now all runs through as expected

Now I am trying to reactivate kudzu without probing the serial ports and gpm with just probing the serial port I do not use for the serial console.

I'll let you know how it turned out.

Paulo, acutally fireing up the getty was not the problem I had, although the information that after the serial parameters (DT9600) I can pass the expected terminal is valuable. Thanks on that.

Volker