topic Re: using serial console in Operating System - Linux

using serial console

K.C. Chan — Wed, 21 Jan 2004 13:18:34 GMT

All,
this is a follow on this link:
"http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=305330"

Here's my grub conf file:

default=0
timeout=10
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal --timeout=15 serial console
title Red Hat Linux (2.4.18-27.7.x)
root (hd0,0)
kernel /vmlinuz-2.4.18-27.7.x ro root=/dev/hda5 console=tty0 console=ttyS0 linux
initrd /initrd-2.4.18-27.7.x.img

Everything works on ttyS0, but when I am at the console, the boot up stop displaying the boot status when it is starting up services in (right after it loaded the kernel) "/etc/rc.d/init.d/" until it gets into a log in prompt. How do I get it all boot messages on tty0 (the acutal physical console which is attached to the server)? Thanks.

Re: using serial console

Tom Ward_1 — Wed, 21 Jan 2004 15:41:43 GMT

Hello K.C.,

You may need to add the key word "text" to the kernel line.

Mine looks like:
title Red Hat Linux SMP (2.4.20-28.9smp)
root (hd0,0)
kernel /vmlinuz-2.4.20-28.9smp ro root=LABEL=/ hdc=ide-scsi text console=ttyS0,57600,vt102
initrd /initrd-2.4.20-28.9smp.img

And I get all the boot status to the serial console.

Regards,
Tom

Re: using serial console

K.C. Chan — Wed, 21 Jan 2004 16:50:30 GMT

I have NO problem gettting boot messages to appear on serial console, it's the actual console which I am having problem with. It stops displaying boot up status after the kernel load. I want to be able to have the "boot up messages" to appear on the serial console as well as the actual physcial console; It doesn't have to appear on both screen at the same time, it could be either or, dedpending which keyboard was hit first during the boot up. Any idea? Thanks.

Re: using serial console

Tom Ward_1 — Wed, 21 Jan 2004 23:48:07 GMT

Hello K.C.,

So you want boot messages to either console: Serial or Local?

The only idea I can come up with is to have two entries in your grub.conf -- one for serial console and one for local console.

title Serial Console Linux (2.4.18-27.7.x)
root (hd0,0)
kernel /vmlinuz-2.4.18-27.7.x ro root=/dev/hda5 console=tty0 console=ttyS0 linux
initrd /initrd-2.4.18-27.7.x.img

title Local Console Linux (2.4.18-27.7.x)
root (hd0,0)
kernel /vmlinuz-2.4.18-27.7.x ro root=/dev/hda5
initrd /initrd-2.4.18-27.7.x.img

You then have to select the correct entry for whichever terminal you're using to boot from.

I hope I understand what you're looking for correctly this time.

Regards,
Tom

Re: using serial console

Stephen P. Schaefer — Thu, 22 Jan 2004 16:18:30 GMT

I believe you want the output from the startup scripts run by /etc/rc.d/rc to go to the serial line. You could change that script to force stdin/stdout/stderr to /dev/ttyS0 with the line

exec /dev/ttyS0 2>/dev/ttyS0

but I would have thought there was some way to inform the kernel itself that /dev/console should go to the serial line (it appears that /dev/console is what init is initially attached to). Have you tried removing /etc/ioctl.save?

Re: using serial console

K.C. Chan — Thu, 22 Jan 2004 16:45:03 GMT

I have not removed /etc/ioctl.save. I want to be able to to Serial line as well as Physical console. The Serial line have no problem getting the ouput of startup scripts. But some reasone the physical console is not getting the output from the startup script? Any idea? Thanks.