Summary ch3

1. Process Concept:

   (1)The program code, also called text section

   (2)Current activity context including program counter, processor registers

   (3)Stack containing temporary data

   (4)Data section containing global variables

   (5)Heap containing memory dynamically allocated during run time

2. Process state:

   (1)new: The process is being created

   (2)running: Instructions are being executed

   (3)waiting: The process is waiting for some event to occur

   (4)ready: The process is waiting to be assigned to a processor

   (5)terminated: The process has finished execution

3. Process Control Block (PCB):

   (1)Each process is represented by a PCB

   (2)Created and managed by the operating system

   (3)Contains the process elements

4. When to switch process:

   (1)Clock interrupt

   (2)I/O interrupt

   (3)Memory fault

   (4)Trap

   (5)System call

5. Context switch: When CPU switches to another process, the system must save the state of the old process and load the saved state for the new process via a context switch

6. interprocess communication (IPC)

   (1)Shared memory

   (2)Message passing