I m tring to figure out the option where i can increase/Decrease the count for local virtual consoles(vtys).
I can able to take upto 6 vtys using (left alt+(F1-F6))
But is there any way i can increase the count ?
One more query
even though i can only take tty upto tty6 why there are tty entries in /etc/securetty file ranging from 1-11(Noob about tty)
This is a Linux thing, not a UNIX one, by the way.
Try ctrl-alt-f8. Do you get a blank screen? It wouldn't switch you to a terminal that doesn't exist, so a blank screen means you have an 8th terminal. It's just not used by anything.
I think there's a hardcoded 12 terminals, one for each function key, handled by the 'vga console' device driver inside the kernel itself. It's somewhat arbitrary and not likely to change. I think even the switching behavior is mostly hardcoded.
But beyond that, they're just devices. What things talk to what devices depends on your system. On my server:
#
# /etc/inittab: This file describes how the INIT process should set up
# the system in a certain run-level.
#
# Author: Miquel van Smoorenburg, <miquels@cistron.nl>
# Modified by: Patrick J. Volkerding, <volkerdi@ftp.cdrom.com>
# Modified by: Daniel Robbins, <drobbins@gentoo.org>
# Modified by: Martin Schlemmer, <azarah@gentoo.org>
#
# $Header: /var/cvsroot/gentoo-x86/sys-apps/sysvinit/files/inittab,v 1.5 2005/12/22 02:03:23 vapier Exp $
# Default runlevel.
id:3:initdefault:
# System initialization, mount local filesystems, etc.
si::sysinit:/sbin/rc sysinit
# Further system initialization, brings up the boot runlevel.
rc::bootwait:/sbin/rc boot
l0:0:wait:/sbin/rc shutdown
l1:S1:wait:/sbin/rc single
l2:2:wait:/sbin/rc nonetwork
l3:3:wait:/sbin/rc default
l4:4:wait:/sbin/rc default
l5:5:wait:/sbin/rc default
l6:6:wait:/sbin/rc reboot
#z6:6:respawn:/sbin/sulogin
# TERMINALS
c1:12345:respawn:/sbin/agetty 38400 tty1 linux
c2:2345:respawn:/sbin/agetty 38400 tty2 linux
c3:2345:respawn:/sbin/agetty 38400 tty3 linux
c4:2345:respawn:/sbin/agetty 38400 tty4 linux
c5:2345:respawn:/sbin/agetty 38400 tty5 linux
c6:2345:respawn:/sbin/agetty 38400 tty6 linux
# What to do at the "Three Finger Salute".
ca:12345:ctrlaltdel:/sbin/shutdown -r now
# Used by /etc/init.d/xdm to control DM startup.
# Read the comments in /etc/init.d/xdm for more
# info. Do NOT remove, as this will start nothing
# extra at boot if /etc/init.d/xdm is not added
# to the "default" runlevel.
x:a:once:/etc/X11/startDM.sh
See the part in red? Terminals 1 through 6 have logins because, in runlevels 2 through 5, init runs agetty for them. (In runlevel 1, you only get ctrl-alt-f1, looks like.) If you copy those lines to make entries for tty8-12, they ought to work. Delete the line for tty6 and you won't get a login prompt on ctrl-alt-f6 next reboot.
Traditionally you get 1-6 as terminal logins, the 7th is saved for your X server(you can switch in and out of GUI just by switching consoles), and the rest are left for custom uses.
So what's your system?
As Corona said, this REEEEALLY depends what flavor of linux + version you're running. For example, if you're running a recent version of Fedora, you won't see anything like that in /etc/inittab. (However, if your inittab does look like that, I can confirm that there's nothing wrong with adding additional respawn lines for higher numbered ttys.)
In other news: chvt is the command you want to switch consoles, especially if you start processes on ones higher than tty12. 