Context switching in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is context switching in operating systems?

Context switching is the process where the CPU switches from one task or process to another, saving the current task's state and loading the next task's state so it can continue running.

beginner

Why is context switching important?

It allows multiple programs to share a single CPU efficiently, giving the appearance that they run at the same time by quickly switching between them.

intermediate

What information is saved during a context switch?

The CPU saves the current process's state, including the program counter, registers, and memory information, so it can resume later exactly where it left off.

intermediate

What is a process control block (PCB) and how does it relate to context switching?

A PCB is a data structure that stores all the information about a process, including its state. During context switching, the OS saves and loads PCBs to switch between processes.

intermediate

How does context switching affect system performance?

Context switching takes time and uses CPU resources, so too many switches can slow down the system. Efficient switching balances multitasking with performance.

What does the CPU save during a context switch?

A The entire hard drive contents

B The current process's state including registers and program counter

C Only the process's memory data

D The user's login password

During a context switch, the CPU saves the current process's state such as registers and program counter to resume later.

Why do operating systems perform context switching?

A To cool down the CPU

B To delete unused files

C To increase the CPU clock speed

D To allow multiple processes to share the CPU

Context switching enables multitasking by letting multiple processes share the CPU.

What is a Process Control Block (PCB)?

A A file storing user passwords

B A type of CPU hardware

C A data structure storing process information

D A network protocol

A PCB holds all information about a process, used during context switching.

Which of these is a downside of frequent context switching?

A Slower system performance

B More free disk space

C Faster internet speed

D Longer battery life

Too many context switches use CPU time and slow down the system.

Context switching happens in which part of the computer?

A CPU

B Hard drive

C Monitor

D Keyboard

The CPU performs context switching to change between processes.

Explain what context switching is and why it is necessary in modern computers.

Think about how your computer runs many programs at once.

Describe what information is saved during a context switch and how it helps the process resume later.

Consider what the CPU needs to remember to continue a task.