The path to Python-the process

Read Catalogue

• Theoretical knowledge
  • Operating System Background knowledge
  • What is a process
  • Process scheduling
  • concurrency and parallelism of processes
  • Synchronous \ asynchronous \ Blocking \ non-blocking
  • Process creation and completion
• Process operations in a Python program
  • Multiprocess Module
  • The creation and multiprocess of processes. Process
  • Process synchronization Control--lock \ semaphore \ Event
    (multiprocess. Lock, multiprocess. Semaphore, multiprocess. Event)
  • interprocess communication--queues and pipelines (multiprocess. Queue, multiprocess. Pipe)
  • Data sharing between processes is--multiprocess. Manager
  • Process pools and multiprocess. Pool

Back to top theoretical knowledge of operating system background knowledge back to top

As the name implies, a process is a process that is being executed. A process is an abstraction of a running program.

The concept of process originates from the operating system, is the core concept of the operating system, and is one of the oldest and most important abstract concepts provided by the operating system. Everything else in the operating system is expanded around the concept of processes.

So to really understand the process, you must know the operating system beforehand, click Enter

PS: The ability to support (pseudo) concurrency can be guaranteed even if there is only one CPU available (this is true for earlier computers). Turning a single CPU into multiple virtual CPUs (multi-channel technology: Time multiplexing and spatial multiplexing + hardware support isolation), without process abstraction, modern computers will no longer exist.

The necessary theoretical basis:

#一 the role of the operating system:    1: Hide ugly complex hardware interfaces, provide good abstraction interface    2: Manage, schedule processes, and compete for hardware with multiple processes # Two multi-channel technology:    1. Generate background: For single core, implement concurrent    PS:    Now the host is generally multi-core, then each core will take advantage of multi-channel technology    has 4 CPUs, a program running in CPU1 encountered IO blocking, will wait until the end of the IO and then reschedule, will be dispatched to 4    CPU any one, specifically by the operating system scheduling algorithm decision.        2. Reuse in space: if there is a multi-channel program    in memory 3. Time reuse: Reuse a CPU time slice       emphasize: Encounter IO cut, take up CPU time too long also cut, the core is to cut the state of the process before saving, so as            to ensure that the next time you switch back, you can continue to run based on the location of the last cut away

Back to the top what is the process

Process is a computer program on a data set on a running activity, the system is the basic unit of resource allocation and scheduling, is the basis of the operating system structure. In the early process design-oriented computer architecture, the process is the basic execution entity of the program, and in the contemporary thread-oriented computer architecture, the process is the container of the thread. A program is a description of instructions, data, and its organization, and the process is the entity of the program.

Narrowly defined: A process is a running instance of a program (an instance of a computer programs, which is being executed). Generalized definition: A process is a running activity of a program with certain independent functions about a data set. It is the basic unit of the operating system dynamic execution, in the traditional operating system, the process is not only the basic allocation unit, but also the basic execution unit.

The path to Python-the process