By default, your Linux system probably supports six "virtual consoles" that you get to with alt-f1 through alt-f6 (from an X session, you may need to add ctrl to the mix, or the SysRq key on Solaris). If you don't run X, however, you may find that six terminals is not enough. You probably have 12 function keys, after all -- why not increase the number of consoles to 12?

To do so, edit the /etc/inittab file. Look for a collection of lines that looks something like this:

1:2345:respawn:/sbin/getty 38400 tty1
2:23:respawn:/sbin/getty 38400 tty2
3:23:respawn:/sbin/getty 38400 tty3
4:23:respawn:/sbin/getty 38400 tty4
5:23:respawn:/sbin/getty 38400 tty5
6:23:respawn:/sbin/getty 38400 tty6

Now simply add 6 more lines to launch the new consoles:

7:23:respawn:/sbin/getty 38400 tty7
8:23:respawn:/sbin/getty 38400 tty8
9:23:respawn:/sbin/getty 38400 tty9
10:23:respawn:/sbin/getty 38400 tty10
11:23:respawn:/sbin/getty 38400 tty11
12:23:respawn:/sbin/getty 38400 tty12

With some distributions you may also need to add the new terminals to /etc/securetty so that you will be able to log in as root on them.