"freeze" terminal output (/dev/tty1) - linux

Question

I'm writing an application (in java) that directly operates on the framebuffer (/dev/fb0).
When I start my app, the cursor of the currently active console still blinks and if i use keyboard-keys like up/down the console will display the recently used commands and overwrite the framebuffer's content.
I was only able to stop the cursor from blinking:
setterm -cursor off > /dev/tty1
Is there a way to totally freeze (and later unfreeze) the console?
It seems like an X-Server does the same thing. If the boot-process runs on GraphicsCard-1 and the X-Server on GraphicsCard-2, the output on GraphicsCard-1 will stop (no blinking cursor) immediately when X starts. I guess mplayer does this, too if setting video-out to the framebuffer.
thanks for any ideas :)

Answer 1

Strictly speaking, the behaviour that you've observed is more of a bug than a feature. It's down to the fact that Linux isn't properly multi-head. What you're seeing is an effect of the X server switching its own, allocated, virtual terminal onto the console. This of course — because only one virtual terminal can be active at a time system-wide — switches out the virtual terminal that was being displayed, even though it was being displayed on another display adapter entirely.
You have to do some of what the X server is doing, and switch your own virtual terminal onto the console.

Answer 2

openvt(1) allows you to open a program in a new virtual terminal, and chvt(1) allows you to switch to another virtual terminal.

Answer 3

it was a little bit more tricky to get what i exactly wanted:
I have to execute (from shell) 2 commands to get the terminal quiet:
chvt 9
setterm -cursor > /dev/tty9
later one can switch back to terminal 1:
setterm cursor > /dev/tty9
chvt 1
I choose terminal number 9 but any number above 7 should be fine. These calls also work if they are executed from within the java application (as JdeBP said, only one virtual terminal system-wide). Only the setterm command requires some additional steps to pipe the output to /dev/tty9:
Runtime.getRuntime().exec("chvt 9");
pipe("setterm -cursor off", "/dev/tty9");
private static void pipe(String cmd, String file) {
FileOutputStream fos = new FileOutputStream(file);
Process p = Runtime.getRuntime().exec(cmd);
InputStream is = p.getInputStream();
int i;
while ( (i = is.read()) != -1 ) {fos.write(i);}
p.waitFor();
fos.close();
is.close();
}
maybe the pipe() method is not optimal, but it worked for me the way it is.