[TriLUG] Stupid question time - Serial terminal and Linux

[Timothy A. Chagnon]

Actually, I know it's possible with a little kernel futzing and lilo. 
Check out your /usr/src/linux-2.?/Documentation/serial-console.txt file
from the kernel source.

Specifically it says you can use the kernel boot line option
console=ttyS0,9600 to get /dev/console to the serial port.  That's just
kernel info though.

It also mentions something about lilo being able to take serial input. 
Then setting the right things for getty to use the serial port for a
login.  

Also in theory, if the box your installing on supports PXE booting, you
could set it to try to boot PXE before hard disk then run pxelinux on
your server, specifying kernel options to do serial through that.

For that matter, if it'll pxe boot, you don't need serial.  Just use a
kickstart file and nfs install source and you've got a auto install. 
Once it's installed you can ssh.  I've recently done this with a lab at
Wake Tech so I know the way to set it up right.  If you go this route
and need help, email me.

The people who would really know lots about this are the guys that built
the Space Simulator cluster at LANL.  All their nodes have no removable
media drives, no keyboards/mice/monitor, just NIC.  They use pxelinux to
do reinstalls so they should know something about it.  The first pdf
paper on their site documents well their exploits about the cluster, and
is a good read, but probably won't have the exact info on doing serial
stuff.  You could try emailing them to get some of their more specific
methods.
http://space-simulator.lanl.gov/

On Tue, 2004-02-24 at 11:04, Mike M wrote:
> On Tue, Feb 24, 2004 at 10:22:53AM -0500, Magnus Hedemark wrote:
> > On Tue, 24 Feb 2004, Mike M wrote:
> > 
> > > Was it a sparc or something that has a reasonable serial interface? If
> > > so then life will be much easier.  It's the x86 archs that are
> > > non-trivial for serial consoles.
> > 
> > The terminal, in my case, is a PC.  The other end is usually, in my case, 
> > a sparc.  You have pretty full access to everything with a serial console 
> > on a sparc (or most other non-PC platforms for that matter).  On a PC, 
> > unless you have special hardware, you can't get into it from the serial 
> > port until the OS is up and even then it has to be specially configured to 
> > give you a serial console.  The non-x86 hardware gives you serial console 
> > at a much lower level, such that you can send a BREAK to the OS and have a 
> > boot PROM prompt.
> 
> I thought that with super-human powers you can load Linux on a x86 over
> COMx.  Googling around doesn't support this possibility though.  i
> 
> Maybe if you had Busybox or a microdistro Linux running in a partition. 
> This basic system can be modified to support serial console.  Then you 
> could use it to install a bigdistro Linux into another partition set, and mod LILO
> to default boot bigdistro the  partition.  I saw that LILO and GRUB will
> communicate over a serial port. It's like having a rescue disk partition always 
> on the HDD.
> -- 
> Mike
> 
> Two hundred years ago, we note mischievously, the average American or 
> European had a standard of living not very much superior to that of the
> average man in India or China. -- dailyreckoning.com
-- 
Timothy A. Chagnon <tchagnon at nc.rr.com>