1. A process is a dynamic entity, from creation to extinction, which is the entire life cycle of a process. Processes can go through a variety of different states, and generally there are three states.
   ①Ready state: The process has obtained all other resources except cpu, waiting for cpu scheduling in the ready queue
   ②Execution status: The cpu has been obtained and all required resources are running
   ③blocking state (waiting state): The process gives up the processor by waiting for the required resources, or the process does not own the processor, and other resources are not satisfied.


2. The PCB contains the descr iption information and control information of the process. It is a concentrated reflection of the dynamic characteristics of the process. The system establishes the PCB of the process while establishing the process. When the process is cancelled, the PCB is also revoked. The system perceives a process based on the PCB