Can a process wake itself up, a process is woken up means .

You can schedule a task to start or stop a specified program or process at a scheduled time.

When a process is woken up, it means that the process goes from a blocking state to a ready state.

When the event expected by the blocked process occurs, if the process has completed or the expected data has arrived, the process concerned (for example, the process that has used up and released the device has been released) will call the wakeup() primitive to wake up the process waiting for the event.

The process executed by the wake-up primitive is to first remove the blocked process from the blocking queue waiting for the event, change the current state of the jujube in its PCB from blocked to ready, and then insert the PCB into the ready queue.

Answer]: The sleep state of process B is also the blocking state, and after the process is awakened, it changes from the blocking state to the ready state.

In Linux, processes that only wait for CPU time are called ready processes, and they are placed in a running queue with a status flag of task running.

Once a running process runs out of time, the Linux kernel's scheduler takes the process away from control of the CPU and selects a suitable process from the running queue to run. Set sleep and wake for Linux processes.

bWhen the event that the process in the waiting queue is waiting for occurs, all processes waiting for the event will be woken up. Obviously, a blocked process cannot wake itself up on its own. There are two ways to wake up a process:

One is to be woken up by a system process. The other is to be woken up by the event process. When the waiting process is woken up by the system process, the system process uniformly controls the occurrence of the event and notifies the waiting process of the message "event occurs".

This causes the process to enter the eggplant ready queue because the wait event has occurred. The wait process can also be woken up by an event. When the event occurs and the process is woken up, there is a cooperative relationship between the event occurrence process and the awakened process.

As a result, the wake primitive can be called by both the system process and the event process. We call the process that calls the wake primitive a wake process.

In the case of a computer, being woken up means that when an event that a process in the waiting queue is waiting for occurs, all processes waiting for that event will be woken up.

Process refers to the program that has been running in the computer, which is the basic unit of the system for resource allocation and scheduling, and is the basis of the operating system structure. In the early computational bending and upgrading structure designed for the process of annihilation, the process was the basic execution entity of the program. In contemporary computer architectures designed for threads, processes are containers for threads. A process is an instance of a program that actually runs, several processes may be related to the same program, and each process can run independently synchronously or asynchronously.

A process is a single run of a program with independent functionality about a collection of data. It can apply for and own system resources, is a dynamic concept, and is an active entity. It is not just the program's **, but also the current activity, represented by the value of the program counter and the contents of the processing register.