Process Management Operations

Process Creation

• Requires :
  Process name,
  Process code + start address
  data + stack
• Kernel creates a PCB (Process Control Block), assigns enough memory and makes the process runnable

Process Deletion ('Killing and removing a process').

• Stop process
• clean up - outstanding I/O, messages etc.
  recover resources (such as memory)
  delete the PCB
• This is difficult to achieve - WHY ?
• What happens when a parent is killed before the child can respond with the result ?

Process Control

• Movement of processes between states - such as halting a process (make unrunnable)
• Schedule a runnable process
• Continue process - make runnable

Also possible to change priorities of processes

Associated with interrupts are processes which perform specific functions, and after completing the activity pass over control to something else.

• process context is saved in PCB when process stops running
• Context is then re-loaded into processor registers when the process starts running again

Kernel maintains an array or linked list of PCBs