Process

Includes:

• OS
• Kernel
• Process:
• PCB and context switch
• Scheduler
• IPC

OS

• OS is software to abstract(simplify) and arbitrate(control) HW system
• like toy shop manager - resource management, policy, mitigate

OS element: abstraction, mechanism, policy

Kernel

distiguish computer platform as 2 level

application needs OS to support HW access

System flow call ex: user process calls OS then return back to user

Process

• Process is instance of executing program
• like an order of toys

page table mapps virtual addr to hysical addr

some physical addr is in the disk

PCB and context switch

• PCB has state of execution(program counter, stack), tmp holding area (mm), might require some HW (io device)
• process control block (PCB) includes:
  1. program counter (pc) - current step of the process (binary)
  2. stack pointer
• Context switch: when 2 or more process switch for CPU (ex: p1 switch to p2), it need to record the stopping point for current process(p1) and also upload the stopping point for incoming process(p2)

Scheduler

scheduler taks next process from ready queue

IPC

• Inter Process Communication