1.Processes are introduced so that programs can execute concurrently

2.

1) The program is just an ordered set of BAI instructions. It has no du meaning in itself, and it is only a static entity. A process, on the other hand, is the execution of the program DAO sequence on a data set. A process is a dynamic entity that has its own life cycle. It is generated by creation, run by scheduling, put in a wait state by waiting for resources or events, and undone by completing tasks. It reflects the whole dynamic process of a program running on a certain data set.

2) Processes and programs do not correspond one to one. When a program executes on different data sets, it becomes a different process. Each process can be uniquely identified by the process control block. This is exactly what the program cannot do. Since the program has no direct connection with the data, even if it is a program executing different data, its instruction set is still the same, so it cannot uniquely identify these programs running on different data sets. In general, a process must have a corresponding program, and only one. A program may not have a corresponding process (because it is not executing), or may have multiple processes (running on several different data sets).

3) The process is also concurrent and interactive, which is also different from the closure of the program.

3.Other processes in concurrent execution have a mutually restrictive relationship. It is sometimes in a running state, sometimes suspended for some reason, in a waiting state, and when the reason for suspending it disappears, it is ready to run again. So you have to distinguish between these states.