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Old 06-03-2009, 10:10 AM   #1
Dims
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System without video card but with serial cable console?


Is it possible to make Linux box which uses serial cable as it's only terminal?
 
Old 06-03-2009, 10:18 AM   #2
david1941
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see http://www.vanemery.com/Linux/Serial...l-console.html

Dave
 
Old 06-03-2009, 10:23 AM   #3
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My distro is Fedora 9.

Reading the following

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

I see, that not all things are applicable, since my inittab is said to configure only default runlevel.
 
Old 06-03-2009, 10:38 AM   #4
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Fedora 9 is an upstart system and you will find all the runlevel codes in /etc/rc.d and the rc.sysinit starts it up.
Running a /chkconfig --list/ should tell all what you have on in runlevel 3. Check google for an HOW-TO that may be more complete.

Dave.
 
Old 06-05-2009, 05:09 AM   #5
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I have success adding the following

console=tty0 console=ttyS0,115200n8

to the end of kernel parameters line in GRUB configuration.

But I have completely black and white text in result (no ANSI coloring). How to fix this?

I am using the same program (PUTTY) to see both COM1 line and SSH, so, the setup of this program may be irrelevant. Looks like linux itself sends text without escape sequences.

How to check this? If this is so, then how to make linux to use escape sequences?

Thanks.
 
Old 06-05-2009, 06:15 AM   #6
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Dims, I used a serial line console for a couple of years but used SSH to actually control the server. I couldn't get the machine to boot without a console and I used the console only to boot. I don't remember ever seeing color (or needing it) as I was just bringing up a server on our local net. I'm pleased you were able to sort it all out. Perhaps the termcap or terminfo docs will be of assistance for color. google is our friend.

Dave

PS Click on the thumbs up icon if a post helps you as it is all we ever get for answering these posts. Don't click if it is not helpful. :-)
 
Old 06-06-2009, 02:32 PM   #7
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So, I have successfully set up serial console on Fedora.

But the problem is that it does not boot if I remove graphics card. I have turned off X11, but may be something is still requires graphics card?

How to make kernel not to use graphics at all?
 
Old 06-06-2009, 03:23 PM   #8
foodown
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Does the machine even post when turned on with no video card?

Some BIOSes will not post without a video controller . . . some have an option to disable this check.

I don't believe that the kernel itself requires a video controller to be present when booting, as my old 486 DNS has not had a video card in it for like nine years.
 
Old 06-06-2009, 08:56 PM   #9
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Most machines will not survive the POST (power on self test) if certain facilities are not present. You will normally hear a beep code from the motherboard that will decode what is keeping it from starting. Unless you have a setting for bypassing the graphics test in the bios, the motherboard will stop. The easiest fix is to put in the cheapest old graphics card (doesn't matter what kind since you will not be using it) you can find and just go forward with the boot sequence.

Dave
 
Old 06-07-2009, 12:35 AM   #10
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Initially I was also thinking, that this was the POST problem -- i.e. system might not loading due to graphics card absence.

But this suggestion was discarded.

I have removed all familiar (for me) graphics options, including GRUB menu, and got boot messages via serial link. I see, that kernel is loading, hence BIOS is configured correctly and computer IS able to boot withoug graphics card.

But the loading process is still hangs now, although this happens later.

Last edited by Dims; 06-07-2009 at 12:37 AM.
 
Old 06-07-2009, 01:05 AM   #11
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What about font changing utility? When booting, I see the moment, when the font (in text mode) slightly changes. This means that font controlling utility loads.

What happen at this stage if graphics card absent?
 
Old 06-07-2009, 05:30 AM   #12
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Assuming it dies in the /etc/rc.sysinit stage, you could follow its progress through the process. Assuming your default runlevel is 3, run a / ls -al /etc/rc.d/rc3.d / to see just what is called and when. rc.sysinit calls them in order; first the Knn (Kills) and then the Snn (Starts) You can compare the point where it dies with this schedule and see when and what process made it die.

What are your kernel parameters in the GRUB configuration?

Dave
 
Old 06-07-2009, 06:02 AM   #13
david1941
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Dims, the reason I asked about the GRUB kernel parameters is that I don't know how your serial console intreprets the boot process. info grub, in Section 7, addresses the serial console and you may need the --dumb option to describe your terminal. I'm sorry -- its been quite a while since I used the serial console terminal and I just don't remember how I had it all set up. I did keep a graphics card installed as it wouldn't boot without it. But maybe it wasn't required. Getting old is hell on my memory but it does have some good effects also; I also forgot the disappointments we all experience in life.

Dave
 
Old 06-07-2009, 06:28 AM   #14
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Will have more details later.
 
Old 06-07-2009, 12:49 PM   #15
Dims
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My grub.conf is follows:

Code:
default=0
timeout=5
#splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console

title Fedora (2.6.27.24-78.2.53.fc9.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.27.24-78.2.53.fc9.x86_64 ro root=/dev/VolGroup00/LogVol00 console=tty0 console=ttyS0,115200n8
        initrd /initrd-2.6.27.24-78.2.53.fc9.x86_64.img
title Fedora (2.6.25-14.fc9.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.25-14.fc9.x86_64 ro root=UUID=5ae17ef1-5d77-46e0-9f34-8f9f935159c8
        initrd /initrd-2.6.25-14.fc9.x86_64.img
 
  


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