Process , Process states , Process Control Block in Operating Systems
- 1. Process, Process States, Process Control Block. AR MS UF ZB
- 2. What Is Process? • Process is a running program that serves as the foundation for all computation. • Process is something that is currently under execution. So, an active program can be called a Process. For example, when you want to search something on web then you start a browser. So, this can be process.
- 3. Process States • Process goes through different throughout the lifecycle during the process execution, which is known as process states. • From start to finish, the process goes through a number of stages. A minimum of five states is required. Even though the process could be in one of these states during execution, the names of the states are not standardised throughout its lifecycle.
- 4. RAM memory
- 5. 1. New/Start State: This is the initial state when a process is first started/created. 2. Ready State: The process is waiting to be assigned to a processor. Ready processes are waiting to have the processor allocated to them by the operating system so that they can run. Process may come into this state after Start state or while running it by but interrupted by the scheduler to assign CPU to some other process. 3. Running State: Once the process has been assigned to a processor by the OS scheduler, the process state is set to running and the processor executes its instructions.
- 6. 4. Wait/ Block State: Process moves into the waiting state if it needs to wait for a resource, such as waiting for user input, or waiting for a file to become available. 5. Terminate State: When a process’s execution is finished, it goes from the run state to the terminate state. The operating systems deletes the process control box (or PCB) after it enters the terminate state.
- 7. What Is Process Control block? • Process control Block is a data structure used in operating system to store all data related information to the process. • Every process will have its own PCB. • PCB of the process will be stored in main memory.
- 8. Process Control Block: Process ID Process State Program Counter Priority General purpose Registers File list Device Info Protection Etc.
- 9. • Process ID : is a unique Identification number which is assigned by the OS at the time of process creation. • Process States : Contains the current state information of the process where it is residing. • Program counter : Contains the address of the next instructions to be executed. • Priority : is a parameter which is assigned by the OS , at the time of process creations. • General purpose Registers : It contains registers information used by the process in order to execute the instructions.
- 10. • File list : In which CPU maintain a list of files that are being opened by a process. • Device Info : A proper list should be maintained that shows which I/O device is being used by which process. • Protection : It also provide protection to a particular process.