ABSTRACT
The important feature of modern operating systems is that they support real-time multitasking, that is, running multiple programs simultaneously. The running programs are called processes. In the viewpoint of the designers of the UNIX system, the core of the operating system is the process, the so-called OS is actually a number of running processes. According to this principle, the creation of process can only be borne by process, that is, the parent-child process creation mechanism. In any case, there is at least one process in the OS, that is, process 0. Also, a special process is responsible for users interacting with the computer, that is, the shell process. In short, everything is the process.
