# Process Management Basics Process management is a key aspect of operating systems, dealing with the creation, scheduling, termination, and coordination of processes. ## Process Creation Processes can be created by other processes through system calls such as `fork()`. The child process inherits properties from its parent and executes concurrently with the parent. ```c #include <stdio.h> #include <sys/types.h> #include <unistd.h> int main() { fork(); printf("Hello World\n"); return 0; } ``` In this example, 'Hello World' is printed twice because the `fork()` call creates a new process that also executes the `printf()` statement. ## Process States A process can be in one of the following states: - **New:** The process is being created. - **Running:** Instructions are being executed. - **Waiting:** The process is waiting for some event to occur. - **Ready:** The process is waiting to be assigned to a processor. - **Terminated:** The process has finished execution. ## Process Control Block (PCB) Each process is represented in the operating system by a process control block (PCB), also known as a task control block. It contains important information about the specific process including: - **Process State:** The state of the process (as described above). - **Program Counter:** The address of the next instruction to be executed for this process. - **CPU Registers:** They include accumulators, index registers, stack pointers, and general-purpose registers, plus any condition-code information. ## Process Scheduling The operating system schedules processes based on a particular algorithm like First-Come-First-Serve (FCFS), Shortest Job Next (SJN), or Round Robin (RR). The choice of the scheduling algorithm impacts the process performance. ## Process Termination A process terminates when it finishes executing its final statement and asks the operating system to delete it with the `exit()` system call. Alternatively, a process can be killed by another using a `kill()` system call. ``` kill(pid, SIGKILL); ``` In this example, the `kill()` function sends the `SIGKILL` signal to the process with the process ID `pid`, causing that process to terminate immediately.