Processes

• What is a process in computing?

• A program in execution.

• An active instance of a program on a computer.

• The entity that can be executed on a processor.

What is the difference between passive and active programs?

• Passive: The program isn't being executed (like a recipe).

• Active: The CPU executes the program's instructions (like cooking with a recipe).

Why does the OS use processes?

To manage resource allocation.

To efficiently switch the CPU among multiple applications.

To use CPU and I/O devices securely and reliably.

What are the essential elements used by a process?

Program Code, possibly shared with other processes.

A set of data associated with the code.

What is meant by interleaving processes?

• Processes take turns executing instructions.

• The OS re-assigns hardware resources among multiple programs.

What is the Two-State Process Model?

Describes processes as either running or not running.

Managed by long-term and short-term schedulers.

How are processes created and terminated?

Creation: The OS builds data structures for management.

Termination: Processes end due to completion, limits, errors, or user request.

What is response time in the context of processes?

The time from when a process is ready to when it's assigned to the CPU.

What is the Six-State Process Model?

Includes 'suspend' states to manage memory better during process execution.

What is the role of the Process Control Block (PCB)?

Stores all process information needed by the OS.

Consists of process identification, processor state information, and process control information.