CHAPTER 3 : PROCESS

CHAPTER 3 : PROCESS

1. Process Termination

   • if parent terminate without invoke, process is orphan
   • if no parent waiting, process is zombie
   • cascading termination
   • parent may delete the execution of child using abort()
   • execute last statement & ask OS to delete it using System Call

2. Context Switch

   • CPU switch to another process
   • context of process represent in PCB
   • Context Switch time is overhead
   • Time dependent on h/w support

3. Process Scheduling

4. Concept

   • Execute Program
     • Batch system
     • Time - shared system
   • Multiple Parts
     • Text section
     • Program counter
     • Heap
     • Data section
     • Stack
   • Process = program in execution . Program - passive Process - active

5. Process Creation

   • Process identify via Process identifier
   • Resource Sharing option
   • Parent process create Child process
   • Address Space
   • Execution Space
   • UNIX

6. Scheduler

   • Long Term
     • Job Schedule - select which process should be brought into ready queue
       • Invoke Frequently
       • control degree of multiprogramming
     • Strive for good mix
     • Process can be describe :
       • I/O bound process
       • CPU-bound process
   • Medium Term
     • Can be added if degree of multiple programming need to be decrease
     • Swapping - Remove process from memory, store on disk, bring back in to continue execution
   • Short Term
     • CPU Scheduler - Select which process should be execute next and allocate CPU
     • Invoke Frequently

7. Process State

   • NEW
   • WAITING
   • READY
   • TERMINATED
   • RUNNING

8. Process Control Block (PCB)

   • Process State
   • Program Counter
   • CPU Register
   • CPU Scheduling information
   • Memory - management information
   • Accounting information
   • I/O status information

9. Process In Memory

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