The concept of process has two main points ：
* first , A process is an entity . Each process has its own address space ,
* Normally , Include text area （text region）, Data area （data region） And stack （stack region）.
* The text area stores the code executed by the processor ; The data area stores variables and dynamically allocated memory used during process execution ; The stack area stores the instructions and local variables of the active procedure call .
* second , Process is a “ Procedures in execution ”. A program is an inanimate entity , Only when the processor gives the program life （ Operating system execution ）,
* It can become an active entity , We call it a process .
* [size=13.125px] Process is the most basic in the operating system , Important concepts . After the emergence of multiprogramming system , In order to describe the dynamic situation inside the system ,
* A concept introduced to describe the activity law of each program in the system , All multiprogramming operating systems are based on processes .
What is a thread , Concept of process ?
* Usually, a process can contain several threads , They can take advantage of the resources owned by the process ,
* In an operating system that introduces threads , Processes are usually used as the basic unit for allocating resources ,
* Thread is regarded as the basic unit of independent operation and independent scheduling , Because threads are smaller than processes , Basically do not own system resources ,
* Therefore, the cost of its scheduling will be much smaller , It can more efficiently improve the degree of concurrent execution among multiple programs in the system .
* The current general operating systems have introduced threads , In order to further improve the concurrency of the system , And regard it as an important index of modern operating system .