A process in an operating system goes through several different states during its lifecycle. These states represent the different stages that a process goes through from creation to termination. Understanding the states of a process is important in order to understand how operating systems manage processes and allocate system resources.
The states of a process in an operating system can be broadly classified into five categories: new, running, waiting, ready, and terminated.
New State :
The new state is the initial state of a process. In this state, the process is created but has not yet started executing. The operating system typically allocates memory and other resources for the process in this state.
For example, when a user starts a new application on their computer, the operating system creates a new process for that application and places it in the new state. The process remains in the new state until the operating system starts executing the process.
Running State :
The running state is the state where a process is currently executing. In this state, the process has been assigned a portion of the CPU time by the operating system and is actively executing its instructions. Only one process can be in the running state at any given time, as the CPU can only execute one process at a time.
For example, when a user starts a word processor application, the operating system assigns CPU time to the process for the word processor and places it in the running state. The process remains in the running state as long as it continues to execute.
Waiting State :
The waiting state is the state where a process is waiting for a resource to become available. A process can enter the waiting state for several reasons, such as waiting for user input, waiting for a file to be read from disk, or waiting for a network connection to be established.
For example, when a user opens a file in a text editor, the text editor process may enter the waiting state while it waits for the file to be read from disk. The process remains in the waiting state until the required resource becomes available.
Ready State :
The ready state is the state where a process is ready to execute but is waiting for the operating system to assign it CPU time. A process in the ready state is waiting for the CPU to become available so that it can start executing.
For example, when a user starts several applications at once, the operating system may place some of the processes in the ready state while it assigns CPU time to other processes. The processes in the ready state are waiting for their turn to execute.
Terminated State :
The terminated state is the state where a process has completed its execution and is no longer running. In this state, the operating system frees up any resources that were allocated to the process, such as memory and file handles.
For example, when a user closes a word processor application, the operating system marks the process for the word processor as terminated and frees up the resources that were allocated to the process. The process remains in the terminated state until it is completely cleaned up by the operating system.
The states of a process in an operating system can change dynamically as the process executes. For example, a process may start in the new state, transition to the running state, then to the waiting state, and then back to the running state as it waits for resources to become available. The operating system is responsible for managing the state transitions and allocating system resources to processes as they move through their lifecycle.
In conclusion, understanding the states of a process in an operating system is crucial in order to understand how operating systems manage processes and allocate system resources. The five main states of a process are new, running, waiting, ready, and terminated, and each state represents a different stage in the lifecycle of a process. The operating system is responsible for managing the state transitions of processes and allocating system resources such as memory and CPU time as they move through their lifecycle.
The operating system is also responsible for ensuring that processes are properly scheduled and that resources are shared fairly among all processes. For example, the operating system may use algorithms such as round-robin scheduling, priority scheduling, or multi-tasking to manage the execution of processes and ensure that each process gets the appropriate amount of CPU time.
In multi-tasking operating systems, multiple processes can be in the ready state at any given time, waiting for CPU time. The operating system uses scheduling algorithms to decide which process should be assigned CPU time next. For example, in priority scheduling, the operating system assigns CPU time to the process with the highest priority. In round-robin scheduling, the operating system assigns CPU time to each process in a cyclic order.
In addition to managing the execution of processes, the operating system is also responsible for handling communication between processes. For example, processes may use inter-process communication mechanisms such as pipes, sockets, or message queues to exchange information. The operating system provides the necessary resources and primitives to support inter-process communication and ensures that communication between processes is secure and reliable.
In summary, the states of a process in an operating system are a key aspect of process management. The operating system uses the states of processes to manage their execution and allocate system resources, and to ensure that processes are scheduled and executed efficiently. Understanding the states of a process and the role of the operating system in managing processes is essential for anyone interested in operating systems and computer systems in general.
