Write a Linux user-mode program to generate a square wave on the parallel port. Start with a frequency of 1 Hz, and increase the frequency to 100 kHz.

1. Connect a logic analyzer or osilloscope to the parallel port, and determine the period and duty cycle of the output signal.
2. Determine how the period and duty cycle vary as you load the system with other processes. Do this for a number of frequencies, such as 1 Hz, 100 Hz, 1 kHz, 10 kHz, and 100 kHz.
3. Repeat using a RT Linux program.

Turn in the following:

1. Your C program
2. Data on the period and duty cycle of the square wave for different frequencies.