[TriLUG] Re: console access through serial port?

[Ben Boulanger]

On Thu, 18 Apr 2002, Rodent of Unusual Size wrote:
> 1. Is there any way to get access to the console through the
>    serial port?  I have another system that does this for VMS
>    and T64U systems (anyone remember VCS?), but it's unclear
>    to me whether Linux supports it -- and, if so, how I can
>    set it up.  I basically want to be able to give an irresistable
>    three finger salute through the serial port if need be, to
>    *force* a crash/reboot.

To get kernel info output to the serial line (and lose it on the VGA 
line), in lilo.conf add:
serial=0,38400n8
	image=blah
        append="console=ttyS0,38400"

and to get a vty on your serial line, in inittab add something like:
	s0:12345:respawn:/sbin/mingetty ttyS0 DT38400 ansi

Then connect up the proper cable (Null modem for computer to computer) and 
run minicom or some other terminal program on it.  

> 2. Provided I can get in, is there any way I can *crash* the
>    system so I can take a look at a dump to figure out WIH was
>    going on to wedge it?

There's a few different things you can do (gdb?) to crash a system, you 
should be able to find that on google... but I wonder if that kernel 
config option "SysRq key" would help you here.  Check the kernel stuff on 
that one.


Ben
-- 

A gem cannot be polished without friction, nor a man perfected without
trials.