Taking a Operating Systems Security class.

Taking a Operating Systems Security class. Need some help with the following questions.

1) Explain different executable file formats and explain how does loader find out how much memory is required by a new program to load.

2) What is process image?

3) • Explain how does C programming API library function exit(0) is used and what is the effect of the execution of such an API function? • What does API call exit(1) mean