What are process states draw a figure that illustrates the relationship of process states

Draw and explain five state process model.

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What are process states draw a figure that illustrates the relationship of process states

The states in the five state process models are:

1) New: The process has not yet been loaded into main memory.

2) Ready: the process is now prepared to execute when given the opportunity.

3) Running: the process is currently being executed.

4) Blocked: Process that is waiting for some event to occur.

5) Exit: Process is released from main memory because it has halted or aborted.

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Applications that have strict real-time constraints might need to prevent processes from being swapped or paged out to secondary memory. A simplified overview of UNIX process states and the transitions between states is shown in the following figure.

Figure 3–2 Process State Transition Diagram

What are process states draw a figure that illustrates the relationship of process states

An active process is normally in one of the five states in the diagram. The arrows show how the process changes states.

  • A process is running if the process is assigned to a CPU. A process is removed from the running state by the scheduler if a process with a higher priority becomes runnable. A process is also pre-empted if a process of equal priority is runnable when the original process consumes its entire time slice.

  • A process is runnable in memory if the process is in primary memory and ready to run, but is not assigned to a CPU.

  • A process is sleeping in memory if the process is in primary memory but is waiting for a specific event before continuing execution. For example, a process sleeps while waiting for an I/O operation to complete, for a locked resource to be unlocked, or for a timer to expire. When the event occurs, a wakeup call is sent to the process. If the reason for its sleep is gone, the process becomes runnable.

  • When a process' address space has been written to secondary memory, and that process is not waiting for a specific event, the process is runnable and swapped.

  • If a process is waiting for a specific event and has had its whole address space written to secondary memory, the process is sleeping and swapped.

    If a machine does not have enough primary memory to hold all its active processes, that machine must page or swap some address space to secondary memory.

  • When the system is short of primary memory, the system writes individual pages of some processes to secondary memory but leaves those processes runnable. When a running process, accesses those pages, the process sleeps while the pages are read back into primary memory.

  • When the system encounters a more serious shortage of primary memory, the system writes all the pages of some processes to secondary memory. The system marks the pages that have been written to secondary memory as swapped. Such processes can only be scheduled when the system scheduler daemon selects these processes to be read back into memory.

Both paging and swapping cause delay when a process is ready to run again. For processes that have strict timing requirements, this delay can be unacceptable.

To avoid swapping delays, real-time processes are never swapped, though parts of such processes can be paged. A program can prevent paging and swapping by locking its text and data into primary memory. For more information, see the memcntl(2) man page. How much memory can be locked is limited by how much memory is configured. Also, locking too much can cause intolerable delays to processes that do not have their text and data locked into memory.

Trade-offs between the performance of real-time processes and the performance of other processes depend on local needs. On some systems, process locking might be required to guarantee the necessary real-time response.


Note –

See Dispatch Latency for information about latencies in real-time applications.


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    States of a process are as following:

    What are process states draw a figure that illustrates the relationship of process states

    • New (Create) – In this step, the process is about to be created but not yet created, it is the program which is present in secondary memory that will be picked up by OS to create the process.
    • Ready – New -> Ready to run. After the creation of a process, the process enters the ready state i.e. the process is loaded into the main memory. The process here is ready to run and is waiting to get the CPU time for its execution. Processes that are ready for execution by the CPU are maintained in a queue for ready processes.
    • Run – The process is chosen by CPU for execution and the instructions within the process are executed by any one of the available CPU cores.
    • Blocked or wait – Whenever the process requests access to I/O or needs input from the user or needs access to a critical region(the lock for which is already acquired) it enters the blocked or wait state. The process continues to wait in the main memory and does not require CPU. Once the I/O operation is completed the process goes to the ready state.
    • Terminated or completed – Process is killed as well as PCB is deleted.
    • Suspend ready – Process that was initially in the ready state but was swapped out of main memory(refer Virtual Memory topic) and placed onto external storage by scheduler is said to be in suspend ready state. The process will transition back to ready state whenever the process is again brought onto the main memory.
    • Suspend wait or suspend blocked – Similar to suspend ready but uses the process which was performing I/O operation and lack of main memory caused them to move to secondary memory. When work is finished it may go to suspend ready.

    CPU and I/O Bound Processes: If the process is intensive in terms of CPU operations then it is called CPU bound process. Similarly, If the process is intensive in terms of I/O operations then it is called I/O bound process. Types of schedulers:

    1. Long term – performance – Makes a decision about how many processes should be made to stay in the ready state, this decides the degree of multiprogramming. Once a decision is taken it lasts for a long time hence called long term scheduler.
    2. Short term – Context switching time – Short term scheduler will decide which process to be executed next and then it will call dispatcher. A dispatcher is a software that moves process from ready to run and vice versa. In other words, it is context switching.
    3. Medium term – Swapping time – Suspension decision is taken by medium term scheduler. Medium term scheduler is used for swapping that is moving the process from main memory to secondary and vice versa.

    Multiprogramming – We have many processes ready to run. There are two types of multiprogramming:

    1. Pre-emption – Process is forcefully removed from CPU. Pre-emption is also called as time sharing or multitasking.
    2. Non pre-emption – Processes are not removed until they complete the execution.

    Degree of multiprogramming – The number of processes that can reside in the ready state at maximum decides the degree of multiprogramming, e.g., if the degree of programming = 100, this means 100 processes can reside in the ready state at maximum.

    What is a process draw the states of process?

    The state of a process is defined by the current activity of the process. New − The process is being created. Running − In this state the instructions are being executed. Waiting − The process is in waiting state until an event occurs like I/O operation completion or receiving a signal.

    What is process state explain it?

    A process moves into the running state when it is chosen for execution. The process's instructions are executed by one of the CPUs (or cores) of the system. There is at most one running process per CPU or core. A process can run in either of the two modes, namely kernel mode or user mode.

    What is process state with example?

    Process state: Each and every process has some states associated with it at a particular instant of time. This is denoted by process state. It can be ready, waiting, running, etc. CPU scheduling information: Each process is executed by using some process scheduling algorithms like FCSF, Round-Robin, SJF, etc.

    What are the 5 Process States?

    This model consists of five states i.e, running, ready, blocked, new, and exit.

    What are the 3 process States?

    Ready State– A state in which a process is ready and waiting for its execution. Blocked State– A state in which a process doesn't execute until and unless a process event occurs, like completion of an Input/Output operation. Running State– A state in which the process is currently executing.

    What is process Process state transition diagram?

    An active process is normally in one of the five states in the diagram. The arrows show how the process changes states. A process is running if the process is assigned to a CPU. A process is removed from the running state by the scheduler if a process with a higher priority becomes runnable.