Process States and Life Cycle

Introduction

• Overview of process states and life cycle
• Importance for competitive exams and university level exams
• Encouragement to like and subscribe for more content

Understanding Process States

• Model created to explain the states a process goes through from start to end
• Kernel does not know process states; it’s a user-level model

Primary Process States

• New:
  • Created process (e.g., program stored in secondary memory)
• Ready:
  • Process in RAM, waiting for CPU time
  • Managed by long-term scheduler, part of multi-programming concept
• Running:
  • Process currently being executed by the CPU
  • Can have multiple processes on multi-processor systems, but typically assumed as uni-processor
• Terminated:
  • Completed process, resources deallocated
• Wait/Block:
  • Process waiting for an I/O operation to complete

Process Scheduling

• Long-Term Scheduler:
  • Responsible for bringing processes into the ready state
  • Facilitates multi-programming by managing processes in RAM
• Short-Term Scheduler:
  • Dispatches processes from ready state to running state
  • Can implement pre-emptive or non-pre-emptive scheduling:
    • Pre-emptive: Process can be interrupted (e.g., high priority process)
    • Non-Pre-emptive: Process runs to completion without interruption

Process Execution

• After dispatching, CPU executes instructions
• If a process requires I/O:
  • Moves to waiting state and CPU handles other processes
• When I/O is complete, it returns to the ready state

Additional States

• Suspended Wait/Block:
  • When the wait queue is full, processes are swapped out to secondary memory
  • Managed by medium-term scheduler
• Suspend Ready:
  • High priority processes can be placed in suspend ready state if the ready queue is full

Task Management in Operating Systems

• Windows Task Manager:
  • Lists all running processes and their states
• UNIX/Linux:
  • Use of PS command to get process information

Conclusion

• Recap of process states: New, Ready, Running, Terminated, Wait/Block
• Importance of understanding scheduling types: Long-term, Short-term, Medium-term & pre-emptive/non-pre-emptive
• Encouragement to review linked videos for deeper understanding of multi-tasking and programming concepts

This summary captures the essential points regarding process states, their life cycle, and scheduling mechanisms within operating systems.