re: virtual dumbness

[Nicolas Pitre <nico@cam.org>]

On Mon, 25 Mar 2002, Dave Mielke wrote:

> You can, somewhat simplistically, think of each virtual console as being the
> root of an entirely different process tree. You're starting a shell in virtual
> console 1 (by starting it from rc.local), and sending all of the output from
> that sehll (and its descendant processes) to the VB2+.

If I'm not mistaken, the VB2+ sits on a serial port.  That serial port is 
totally separae from virtual consoles.  The serial port can be a "console" 
of its own.  However, Linux presents a console abstraction for the 
computer's video output and keyboard input.  The fact that they are called 
virtual consoles is because the kernel fakles multiple console terminals but 
all multiplexed on the same screen and keyboard.

Therefore, if a process (or better yet a getty) is started on a serial port, 
then it is considered as yet another console separate from the others.  To 
multiplex multiple "consoles" over a serial port, then the only solution is 
to use the 'screen' program.

More on that shell started from rc.local: this is really not the best way to 
handle this.  Instead, the following line should be added to /etc/inittab:

S0:12345:respawn:/sbin/getty ttyS0 9600 vt100

or, if agetty is installed on your system instead of getty:

S0:12345:respawn:/sbin/agetty 9600 ttyS0 vt100

One of those lines, along with the already existing ones for the virtual
consoles, will add another console device to the existing ones, i.e. through
the serial port.  All console signals (CTRL-Z & al) will work without any
trouble, etc.


Nicolas