Difference Between Process, Parent Process, and Child Process

You may use this article to compare Process, Parent Process, and Child Process in great depth. Let's first define Process, Parent Process, and Child Process before comparing them.

What is a Process?

A process refers to an instance of a computer program that is being executed by the operating system. It is a running instance of a program that has its unique process ID (PID), address space, and system resources such as file descriptors, environment variables, and CPU time. Each process is isolated from other processes, and they can communicate with each other through inter-process communication (IPC) mechanisms.

Difference Between Process, Parent Process, and Child Process

In simple terms, a process is a running program that has been loaded into the computer's memory and is currently being executed. When a program is launched, it becomes a process, and it continues to run until it completes its task or is terminated by the operating system or a user. Processes are essential to the functioning of modern operating systems and enable multitasking, which allows several programs to run simultaneously on a computer.

What is a Parent Process?

A parent process is a process that creates another process, known as a child process. When a parent process creates a child process, it passes some data or instructions to the child process. The parent process can also monitor and control the child process's behaviour, including terminating it if necessary.

Parent processes are an important concept in operating systems, as they enable the creation of new processes and the coordination of multiple processes. The relationship between parent and child processes can be visualized as a tree structure, with the parent process at the top of the tree and the child processes branching out below it.

In some operating systems, such as Unix and Linux, the parent-child relationship between processes is established through a system call called "fork." When a parent process calls fork, it creates a copy of itself, which becomes the child process. The child process inherits some of the parent process's properties, such as its memory and file descriptors. The child process can then execute a different program using the "exec" system call.

Overall, parent processes play a crucial role in the creation and coordination of multiple processes in an operating system.

What is a Child Process?

A child process is a process that is created by another process, known as the parent process. When a parent process creates a child process, it passes some data or instructions to the child process. The child process is an independent entity that can execute a different program or perform a different task from the parent process.

The relationship between a parent process and a child process is hierarchical, with the parent process at the top of the tree and the child process branching out below it. The parent process can create multiple child processes, and each child process can also create its child processes. This hierarchical relationship between processes is fundamental to multitasking, which allows several programs to run simultaneously on a computer.

Child processes can inherit some of the parent process's properties, such as its memory and file descriptors, but they can also allocate their resources and control them independently. The child process can execute a different program using the "exec" system call. Once the child process has completed its task, it can terminate itself or be terminated by the parent process.

In operating systems like Unix and Linux, the creation of child processes is established through a system call called "fork." The fork system call creates a copy of the parent process, and the child process inherits some of the parent process's properties. The child process can then execute a different program using the "exec" system call.

Overall, child processes are essential to the functioning of modern operating systems and enable multitasking, which allows several programs to run simultaneously on a computer. They also play a crucial role in the creation and coordination of multiple processes in an operating system.

Difference between Process, Parent Process, and Child Process

Characteristic	Process	Parent Process	Child Process
Creation	A process can be created by the operating system or by another process.	A parent process creates a child process using system calls such as "fork".	A child process is created by a parent process.
Identification	Each process has a unique process ID (PID).	The parent process has a PID that is different from its child processes.	Each child process has a different PID from its parent process and other child processes.
Memory	Each process has its own address space and memory allocation.	Each process has its own address space and memory allocation.	Each child process has its own address space and memory allocation.
Execution	A process can execute a program or perform a task.	The parent process can also execute a program or perform a task, but it can also create child processes.	A child process can execute a program or perform a task independently from its parent process.
Relationship	A process can have no parent or child processes.	The parent process can have multiple child processes.	A child process can have no or one-parent process.
Termination	A process can be terminated by the operating system or by a user.	The parent process can terminate its child processes, and a child process can terminate itself.	A child process can be terminated by its parent process.
Resources	Each process has its own system resources, such as file descriptors and environment variables.	The parent process and its child processes can share system resources.	Each child process has its own system resources, separate from its parent process and other child processes.
Communication	Processes can communicate with each other through inter-process communication (IPC) mechanisms.	The parent process and its child processes can communicate with each other using IPC mechanisms.	Child processes can communicate with each other using IPC mechanisms.
Control	A process can't control other processes.	The parent process can control its child's processes, such as terminating them or changing their priorities.	A child process can't control other processes, including its parent process.
Inheritance	A process can't inherit properties from other processes.	Child processes inherit some properties from their parent processes, such as memory and file descriptors.	A child process can't inherit properties from other child processes.
Scheduling	Processes are scheduled by the operating system.	The parent process and its child processes are scheduled by the operating system.	Child processes are scheduled by the operating system.
Priorities	Processes have their priorities set by the operating system or a user.	The parent process can set the priorities of its child's processes.	Child processes have their priorities set by the operating system or a user.