In this chapter, we discuss the powerful programming techniques in the C language for implementing high-performance computing-related applications. Specifically, we discuss the multiprocessing and multithreading programming techniques to implement parallel processing applications. First, we discuss how to create and manage multiple processes in a reliable manner using Linux system calls such as fork, exec, and wait. It helps you in implementing parallel processes, assigning specific jobs to each process, and handling performance and reliability-related issues of process management.