General :: Real Time Processes ?

I've got the following problem:

1. I start two bash windows

2. In one of them I start a script test1:

Code:

This script puts a natural number 5 times a second.

3. Then in the second bash window I type (as root):

Code:

The script test2 looks as follows:

Code:

While true; do
true;
done

During the following 15 seconds test2 is the process with the highest real-time priority. As far as I know the script doesn't perform any system calls so it shouldn't be suspended even for a minimal timeslice. My question is: why the process test1 manages to put a few numbers on the screen before test2 stops. I thought that test2 would exclusivly own the processor for 15 seconds.