Shanghai day30-- concurrent programming, processes

table of Contents

• History of operating system development

• Process theory

• Create a process in two ways (******)

• Methods join process

• Process object and other methods

• Inter-process data isolation from each other

• Daemon

• Mutex (*****)

 

 

First, the history of the operating system

Multi-channel programming techniques

      The so-called multi-channel programming technology, refers to allow multiple programs at the same time and run into the memory. I.e., while the plurality of programs into memory, and allowing them alternately run in the CPU, they share a variety of hardware and software resources in the system. When a program due to the I / O request to suspend operation, CPU will immediately turn to run another road program.

Features multi-channel technology

1 . Spatial multiplexing on 
        a plurality of programs share a common set of computer hardware
    
     2 . Multiplexed in time 
        switching + save state
             1 when an operation of the operating system program encounters IO cpu deprive the program execution authority (improve the cpu utilization and does not affect the performance of programs)
                
            
             2. when a program for a long time occupied cpu cpu operating system will deprive execute permission of the program (reducing the performance of programs)

 

Second, the process theory

What is the process? What is the program

Third, the process of creating two ways (******)

Fourth, the process method join

Fifth, the process object and other methods

Six inter-process data isolation from each other

Seven, Daemon

Eight, mutex (*****)