python 38 assignment

Homework today

• Brief history of operating system development

  Manual stage: paper tape technology

  Single-channel batch processing system: single-channel input, serial batch processing

  Multi-channel batch processing system: multi-channel input, batch processing

  Time-sharing operating system: divide time into smaller units and allocate time for processing

  Real-time operating system: weight different tasks and give priority to high weights

  Other operating systems: distributed, networked, personal computer operating systems

• Briefly describe the process development history and algorithm evolution

  First come first serve

  First service of time period

  Time slice round forwarding + multi-level feedback queue

• Brief description of multi-channel technology

  When a task occupies the CPU, the input and output devices will not be idle, preparing for the next task to run

• Briefly introduce the concept of synchronous asynchronous blocking non-blocking

  Synchronization: After sending a request to a program, keep waiting for the result

  Asynchronous: After sending a request to a program, it will not wait forever, triggering the information feedback mechanism when there is a result

  Blocking: Due to the Io operation, the CPU will process other programs.

  Non-blocking: in ready or running state

• Two ways of writing process creation

  #  方式一:直接调用函数
  from multiprocessing import Process
  import time
  
  
  def task(name):
      print(f'子进程{name}开始')
      time.sleep(3)
      print(f'子进程运行{name}结束')
  
  
  if __name__ == '__main__':
      #  Process是一个类,调用类生成对象p,需要传参
      print(f'主进程开始')
      p=Process(target=task, args=('1',))
      #  所有容器类型哪怕只有一个参数后面也要加逗号,防止是元组
      p.start()
      print(f'主进程结束')
  
  #  方式2:类的继承
  
  
  class MyProcess(Process):
      def __init__(self,name):
          super().__init__()
          self.name=name
  
      def run(self):
          print(f'子进程{self.name}开始')
          time.sleep(3)
          print(f'子进程{self.name}运行结束')
  
  
  if __name__ == '__main__':
      print(f'主进程开始')
      p = MyProcess('1')
      p.start()
      print(f'主进程结束')