[vox-tech] complete serial console success! (was: Re: minicom help)

vox-tech@lists.lugod.org vox-tech@lists.lugod.org
4 Jan 2002 13:16:53 -0800


Hey, this could go on the lugod faqs page
-sp

On Fri, 04 January 2002, Henry House wrote:

> 
> keywords: grub, bootloader, serial ports, console, headless server
> 
> On Thu, Jan 03, 2002 at 05:15:34PM -0800, Henry House wrote:
> [...]
> > I still can't get grub to display anything to the serial port, using the
> > instructions from the info page, namely to add the following to the grub
> > installation script:
> > 
> > 	serial --unit=0 --speed=9600
> > 	terminal serial
> > 
> > I shall try fiddling with the grub setup.
> 
> Okay, I finally have it :-). Steps:
> 
> 1. Connect server (headless box) to client (with monitor and keyboard) via a
>    null-modem serial cable. If I can find the parts I plan to re-wire the
> 	link with cat5 cable instead, to make it easier to fit the cable into a
> 	raceway.
> 
> 1. Linux and grub both use 9600 baud, 8n1, with NO flow control. Configure
>    minicom on client appropriately.
> 
> 2. The grub info document is misleading. You do not need to reinstall grub to
> 	enable serial IO, unless your grub binaries have been compiled without
> 	serial support (Debian's is fine out of the box). Just add the following
> 	lines to /boot/grub/menu.lst:
> 
> 		serial --unit=0 --speed=9600
> 		terminal --timeout=0 serial
> 
> 	and your bootloader will be useable in the serial terminal the next time
> 	it runs.
> 
> 3. Compile a kernel with serial drivers and console on serial support enabled
> 	(not as modules). I also removed all the video drivers, mouse and
> 	keuyboard drivers, and the VGA virtual terminal driver, since I have no
> 	use for them. If you leave the video drivers in, you must append
> 	'console=ttyS0' to the kernel arguments. Otherwise the first serial port
> 	is used by default. This lets you see the kernel's messages as it loads.
> 
> 4. Add a line to /etc/inittab to run a getty process on the serial port
>    (otherwise after the kernel is up you will be unable to log in). Example:
> 
> 		T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
> 	
> 	Run 'telinit q' to test.
> 
> 5. Optional: add ttyS0 to /etc/securetty. This allows root to log in on this
>    terminal.  Otherwise you must log in as a regular user and use su.
> 
> 6. Reboot and pat yourself on the back if all went according to plan :-).
> 
> -- 
> Henry House
> The attached file is a digital signature. See <http://romana.hajhouse.org/pgp>
> for information.  My OpenPGP key: <http://romana.hajhouse.org/hajhouse.asc>.