Operating Systems Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is indicated by the 'created' or 'new' state of a process?

The process is waiting for additional resources.

The process has just finished execution.

The process is currently executing on a CPU.

The process awaits admission to the 'ready' state. (correct)

Which state describes a process that is currently executing on the CPU?

Blocked

Terminated

Running (correct)

Ready

What happens to a process that has finished its execution?

It returns to the ready state.

It is moved to the created state.

It enters a waiting state.

It is terminated. (correct)

In which state does a process wait for the allocation of CPU time and other resources?

Waiting Signup and view all the answers

Which of the following states implies that the process cannot execute until a specific condition is met?

Blocked Signup and view all the answers

What does the operating system do when a process in the running state exceeds its allocated time slice?

It swaps the process back to the ready state. Signup and view all the answers

What is part of a process's control block that helps manage its execution?

Process ID Signup and view all the answers

Which statement about program data and code in a process is correct?

Program code can be shared among multiple processes, but data can vary. Signup and view all the answers

What is a characteristic of a Process Control Block (PCB)?

It contains the current state of the process. Signup and view all the answers

Which of the following components is NOT typically included in a Process Control Block?

User account details Signup and view all the answers

What happens to a process control block if a process enters the 'terminated' state?

It may become a zombie if not removed. Signup and view all the answers

Which of the following best describes a context switch?

Reassigning CPU from one task to another. Signup and view all the answers

Why must the PCB be stored in a protected area of memory?

To prevent unauthorized access to critical process information. Signup and view all the answers

Which of the following is true about process scheduling using a PCB?

PCBs help manage the allocation of CPU time to different processes. Signup and view all the answers

What is indicated by the 'register save area' in a PCB?

It saves the current register values for the process. Signup and view all the answers

What does a pointer to the parent process in a PCB signify?

It indicates the origin process that created this process. Signup and view all the answers

What happens during context switching?

The kernel saves the context of the current process and loads a new one. Signup and view all the answers

Which of the following events can lead to a context switch?

The process needs to wait for I/O to complete. Signup and view all the answers

Which type of resource is characterized by the ability to take it away and give it back later?

Pre-emptible resources. Signup and view all the answers

What is a major consequence of deadlock in resource allocation?

Processes are starved of resources indefinitely. Signup and view all the answers

What is a key responsibility of an operating system in managing resources?

To ensure high-level utilization and fairness. Signup and view all the answers

What is scheduling in the context of operating systems?

The process of determining which processes in the ready queue run next. Signup and view all the answers

Which of the following is NOT a technique for resource sharing among competing processes?

Permanent allocation of resources to high-priority processes. Signup and view all the answers

What is the main role of a scheduler within an operating system?

To decide the sequence of processes running on the available CPUs. Signup and view all the answers

What is the main function of an operating system in process management?

To allocate and schedule resources for processes Signup and view all the answers

Which of the following statements best describes multiprogramming?

It involves running multiple processes simultaneously to maximize CPU usage. Signup and view all the answers

How does a process differ from a program?

A process is a dynamic entity that requires resources during execution. Signup and view all the answers

Which statement correctly defines a child process?

A process created by a main process. Signup and view all the answers

Why are programs considered static while processes are dynamic?

Programs exist on disk until loaded into memory, while processes change states. Signup and view all the answers

Which of the following is NOT a responsibility of the operating system concerning processes?

User interface design. Signup and view all the answers

What does process synchronization involve?

Ensuring that processes execute in a coordinated manner. Signup and view all the answers

Which of the following distinguishes a program's resource requirements from a process?

A process requires CPU time, memory, and I/O devices. Signup and view all the answers

Which scheduling system allows the scheduler to interrupt a running job?

Preemptive scheduling Signup and view all the answers

What occurs during a preemptive scheduling decision?

A process switches from running to waiting. Signup and view all the answers

What term describes processes that rely heavily on IO operations?

IO-bound processes Signup and view all the answers

Which of the following criteria is NOT a focus of CPU scheduling?

User satisfaction Signup and view all the answers

Which timing measurement reflects the duration from submission to completion of a process?

Turnaround time Signup and view all the answers

What type of scheduling requires a job to terminate before the scheduler can take over?

Non-preemptive scheduling Signup and view all the answers

Which scheduling principle emphasizes equal distribution of CPU time to all processes?

Fairness Signup and view all the answers

Which metric defines the average time a process spends waiting in the ready queue?

Waiting time Signup and view all the answers

Study Notes

Operating System Responsibilities

The OS manages processes by: creating, deleting, suspending, resuming, and providing mechanisms for synchronizing and communicating between them.
Allocating and scheduling resources for processes.

Multiprogramming and Multitasking

Technique where multiple tasks (processes) share common processing resources, like the CPU.
Aims to maximize CPU utilization by running multiple programs simultaneously.

Process vs. Program

Program: A set of instructions executed by a computer.
Process: An instance of a program in execution, active and consuming resources.

Distinction between Program and Process

Program is static, residing in secondary memory.
Process is dynamic, existing only during execution in main memory.
Program is a passive entity, containing instructions.
Process is an active entity, requiring resources for execution.
Program has two components: code and data.
Process has additional information for management and execution.

Process States

Created (New): Process is first created and awaits admission to the "ready" state.
Ready: Process is loaded into main memory and awaits execution.
Running: Process is actively executing on the CPU.
Waiting: Process is waiting for a resource (e.g., I/O) to be available.
Terminated: Process has completed execution or been explicitly killed.

Process Control Block (PCB)

Contains information about a process for management, including state, identification (process ID - PID), parent/child relationships, priority, memory locations, register values, and I/O information.

Location of the PCB

The PCB is typically placed in a protected area of memory, often at the beginning of the process' kernel stack.

Context Switching

Reassigning CPU from one task to another.
Involves saving the context (CPU registers and data) of the current process and loading the context of the new process.
Triggers when a process exits, exhausts its time slice, requires unavailable resources, or a higher-priority process becomes ready.

Resource Allocation Concepts

Pre-emptible Resources: Can be taken away and given back later (e.g., CPU).
Non-pre-emptible Resources: Once assigned, cannot be reused until voluntarily released (e.g., disk blocks).

Scheduling Concepts

Scheduling: Determining which process in the ready queue will run next.
Scheduler: Software responsible for assigning processes to CPUs.
Preemptive Systems: The scheduler can interrupt a process and force a context switch.
Non-preemptive Systems: The scheduler waits for the running process to voluntarily block or terminate.
Scheduling Decisions: Occur when a process switches states (ready, running, waiting, terminated).

Scheduling Assumptions

A pool of ready processes vying for the CPU.
Processes compete for resources.
The scheduler aims to allocate the CPU fairly and optimize performance criteria.

Process Behavior and CPU Scheduling

CPU/IO Burst Cycle: Processes alternate between periods of CPU execution and I/O operations.
IO-Bound Processes: Characterized by frequent I/O operations and short CPU bursts.
CPU-Bound Processes: Perform extensive computation and have fewer, longer CPU bursts.

Criteria for CPU Scheduling

CPU Utilization: Keeping the CPU busy as much as possible.
Throughput: Number of processes completed per time unit.
Turnaround Time: Time elapsed from submission to completion of a process.
Waiting Time: Time spent in the ready queue.
Response Time: Time from request submission to the first response.
Fairness: Providing equal CPU time to each process.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the fundamental responsibilities of operating systems, including process management and resource allocation. It also distinguishes between programs and processes, along with the concepts of multiprogramming and multitasking. Test your understanding of these key concepts in operating systems.