In computing, a process refers to a program or a set of instructions that is currently being executed by a computer's central processing unit (CPU). In an operating system (OS), a process is a fundamental unit of work that can be managed and scheduled independently by the OS.
A process typically consists of four components: an executable program code, data associated with the program, a set of resources required to execute the program, and a process control block (PCB) that contains information about the process's current state, including its memory allocation, execution status, and other vital statistics.
When a program is executed, the OS creates a new process and allocates memory and resources required for the program to run. The OS also assigns a unique process ID (PID) to the process and stores information about it in the PCB. The OS can then manage and schedule the execution of the process based on its priority and other factors.
Multiple processes can run simultaneously in a computer system, and the OS can switch between them quickly, giving the illusion of parallel execution. The ability to manage processes is a critical feature of modern operating systems, as it allows multiple programs to run simultaneously and ensures that each program receives the resources it needs to function correctly.
Types of Process in OS
In an operating system, there are several types of processes that can be classified based on their characteristics and behavior. Some common types of processes are:
System processes: These are processes that are created by the operating system and run in the background to provide services to other processes. Examples include device drivers, system daemons, and system utilities.
User processes: These are processes that are created by users to perform specific tasks. Examples include word processors, web browsers, and email clients.
Interactive processes: These are user processes that require interaction with the user, such as a command-line shell or a graphical user interface.
Batch processes: These are non-interactive processes that are scheduled to run at a specific time or when certain conditions are met. Examples include backups, database maintenance tasks, and batch file processing.
Real-time processes: These are processes that require immediate and predictable response times, such as control systems for machinery or medical equipment.
Foreground processes: These are processes that are currently executing and have the user's attention. They typically have a higher priority than background processes.
Background processes: These are processes that are running but do not have the user's attention. They typically have a lower priority than foreground processes and are often used for tasks that can be done in the background, such as printing or file transfers.
The classification of processes can vary depending on the operating system and the specific context in which they are used.
Process Life Cycle in Operating System
The process life cycle in OS that describes the various stages that a process goes through from its creation to its termination. The following are the typical stages of the process life cycle in an operating system:
Creation: This is the first stage of the process life cycle, where a new process is created by the operating system in response to a user request or a system event.
Ready: In this stage, the process is ready to run but is waiting for the CPU to be assigned to it. The process remains in the ready state until the CPU becomes available.
Running: The process is in this stage when it is executing on the CPU.
Blocked: The process may be blocked and waiting for an event to occur before it can continue. Examples of events that may cause a process to become blocked include waiting for user input, waiting for data to be read from a file, or waiting for a network connection.
Terminated: When a process has completed its task or has been terminated by the user or the operating system, it moves into the terminated state. In this state, the process is no longer running, and its resources are released by the operating system.
The process life cycle is a continuous cycle, and processes move between the various states depending on their current status and the events that occur. The operating system is responsible for managing the process life cycle and ensuring that processes are properly scheduled and terminated.
