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Connection of procedures, processes, and operations
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Overview of procedures, processes, and operations
Program: A computer program is a set of instructions that can be recognized and executed by a computer. It runs on an electronic computer and is an information tool that meets people's needs
[Program is a sequence of instructions, a static concept]
Process: A process is a running activity of a program on a certain data set in a computer. It is the basic unit of the system for resource allocation and scheduling, and it is the foundation of the operating system structure.
[A process can apply for and own system resources. It is a dynamic concept and an active entity. It is not only the code of the program, but also the current activity, which is represented by the value of the program counter and the content of the processing register, and is mainly composed of PCB (program control block), program and data collection]
Job: In some operating systems, the job is the execution unit that the computer operator (or a program called the job scheduler) gives to the operating system
[A job is a task that a user needs to complete by a computer, and it is a collection of tasks that a computer is required to do. The completion of a job involves four stages: job submission, job storage, job execution, and job completion. The job includes three parts: procedures, corresponding data, and job instructions]
Association of programs, processes, and jobs
- A job is a task entity that a user submits a task to a computer. After the user submits the job to the computer, the system puts it in the job waiting queue in the external memory for execution
- The process is the execution entity that completes the user's tasks, and is the basic unit that applies to the system for the allocation of resources. Any process, as long as it is created, there is always a corresponding part in the memory
- A job can be divided into several processes to complete, a job can be composed of multiple processes, and must be composed of at least one process, the reverse is not true
- The concept of job is mainly used in batch processing system, there is no concept of job in time-sharing system; the concept of process is used in almost all multi-program systems
- A process is the basic unit that competes for the limited resources of a computer system. It is the basic unit of process processor scheduling. It is the process in which a program is executed on the processor at a time. It is a dynamic concept; a program is a static concept.
- The process consists of two parts: program and data
- The process can describe concurrency more realistically, while the program cannot
- The process has the function of creating other processes; the program does not
- A program can be used as a running program for multiple processes; a process can also run multiple programs
[Simply put: a job can be divided into several processes to complete, the entity of each process is a collection of programs and data]
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I am Tong Xiaobai, a computer noob