Thread status: 1. New status. After the thread object is created, it enters the new status; 2. Ready state, also known as "executable state"; 3. In the running state, the thread obtains the CPU permission for execution; 4. Blocking state; 5. State of death. Thread is the smallest unit that the operating system can schedule operations. It is included in the process and is the actual operation unit in the process. A thread refers to a single sequential control flow in a process. Multiple threads can be concurrent in a process, and each thread executes different tasks in parallel. The entities in the thread basically do not have system resources, but have some essential resources that can ensure independent operation. Thread entities include programs, data, and TCB. Thread is a dynamic concept, and its dynamic characteristics are described by thread control block (TCB).