My desktop system is:$ uname -aLinux xmachine 3.0.0-13-generic #22-Ubuntu SMP Wed Nov 2 13:25:36 UTC 2011 i686 i686 i386 GNU/LinuxBy running ps a | grep getty, I get this output:  900 tty4     Ss+    0:00 /sbin/getty -8 38400 tty4  906 tty5     Ss+    0:00 /sbin/getty -8 38400 tty5  915 tty2     Ss+    0:00 /sbin/getty -8 38400 tty2  917 tty3     Ss+    0:00 /sbin/getty -8 38400 tty3  923 tty6     Ss+    0:00 /sbin/getty -8 38400 tty6  1280 tty1     Ss+    0:00 /sbin/getty -8 38400 tty1  5412 pts/1    S+     0:00 grep --color=auto gettyI think ttyX processes is for input/ouput devices but I am not quite sure. Based on this I am wondering that why there are 6 ttyX processes running? I have only one input devices(keyboard) actually.
why there are six getty processes running on my desktop?
linux;terminal;console
This shows because one getty process is running on each virtual console (VC) between tty1 and tty6. You can access them by changing your active virtual console using Alt-F1 through Alt-F6 (Ctrl-Alt-F1 and Ctrl-Alt-F6 respectively if you are currently within X).For more information on what a TTY is, see this question, and for information on virtual consoles, see this Wikipedia article.