What is the concept of why a process should be introduced

Why is the concept of processes introduced in operating systems? What kind of impact will it have?

In order to enable programs to be executed concurrently in a multi-channel program environment, and to control and describe the programs executed concurrently, the concept of process is introduced into the operating system. The purpose of introducing the process is to clearly describe the internal laws of the dynamic system, and to effectively manage and schedule the programs that enter the main memory of the computer system.

A process is an application that is running in a system; A thread is the basic unit of the system that allocates processor time resources, or a unit that executes independently within a process.

For an operating system, its scheduling unit is a thread. A process includes at least one thread, which is often referred to as the main thread. A process that starts with the execution of the main thread and then creates one or more additional threads is known as multithread-based multitasking.

Improve the utilization of resources and correctly describe the execution of the program.

1. Process is the basic unit of resource allocation and scheduling, and is the basis of OS structure.

2. A process is a running activity of a program with independent functions about a certain data collection. 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.

3. The reason why the operating system introduced the concept of process:

From a theoretical point of view, it is an abstraction of the process of a running program;

From the perspective of implementation, it is a data structure whose purpose is to clearly describe the internal laws of a dynamic system and effectively manage and schedule the programs that run into the main memory of a computer system.

Answer]: A process is a one-time execution of a program, which can be executed concurrently with other programs.

The reasons for the introduction of the concept of "process" are:

1) The sequential program is executed strictly in order, which is closed and reproducible, but the sequential execution efficiency of the program is very low.

2) After the emergence of multi-channel program design, the concurrent execution and sharing of leased programs are realized, which improves the efficiency of the system and the resource utilization rate of the system, but brings new problems.

3) The concurrent execution of the program destroys the closed and reproducible nature of the program, and the activities executed by the program and the machine are repeatedly corresponding, and there may be a mutual constraint relationship between the concurrent programs.

Definition of Process: "Process" is one of the most basic and important concepts of an operating system. But to date there is no definite and uniform description of this concept.

Several definitions of processes are described below. A process is an execution of a program. l Processes are computations that can be executed in parallel.

A process is an activity that occurs when a program is executed sequentially on a processor with the data it uses. A process is the process by which a program runs on a collection of data. It is an independent unit of the system for resource allocation and scheduling.

2) Characteristics of the process: dynamic: it is the execution of the program; Concurrency:

Processes can be executed concurrently; Independence: It is an independent unit of the system for resource allocation and scheduling; Asynchronicity: mutual constraints between processes, so that there is a gap in process execution; Structural:

Processes are structured.; 3) The main differences between process and procedure: (1) the program is permanent; The process is temporary, it is the execution of the program on the dataset, there is creation and revocation, and the existence is temporary; (2) The procedure is a static concept, and the process is a dynamic concept; (3) the process is concurrent, while the program does not; (4) Processes are the basic units of competition for computer resources, and programs are not.

5) Processes and programs do not correspond one-to-one: a program can correspond to multiple processes, that is, multiple processes can execute the same program; A process can execute one or several programs.

Typically processes have one of the following three states during their lifetime:

1. Ready: The process is ready to run, and the process has been allocated to the required system resources, as long as the CPU is obtained, it can be executed.

2. Running state: It means that the process has obtained the CPU and is executing, and in a single processor system, at most only one process is in this state.

3. Block state: refers to the process being executed, and a certain time occurs during the execution process (such as: IO request, application buffer failure, etc.).