Operating system Notes (iii) management of process management

• Scheduling

1. Context Switch:save Context (PCB), restore context (PCB). Overhead
2. How to maintain the status of individual processes: PCB + queue (Job queue, ready queue, I/O device queue)
3. Who's the next to run? ：

• • CPU Scheduler (short 100ms): Good repsonse time
  • Admission Scheduler (long-term 1+min): the degree of multiprogramming and mix of Cpu-and I/O-bound processes
  • Memory Scheduler (Interim): Reduce the degree of multiprogramming according to available memory

• Process actions
  1. Create: Parent-child process. Fork, CreateProcess
  2. Process collaboration: producer, consumer issues
     • interprocess communication ipc[System call]
     • Shared memory [manage alone] "key point: Stop production and consumption conditions. 】
  3. Terminate
• Ipc:pipe Pipe, FIFO
  • Anonymous pipe: Parent-child process, simplex (0 for read, 1 for write)
  • Named pipe: Any process, single, duplex

Operating system Notes (iii) management of process management