---
title: "What is the difference between user and kernel modes in operating systems?"  
description: "What is the difference between user and kernel modes in operating systems?"  
author: "Utpal Vishwas"  
published: 2023-07-13  
updated: 2023-07-14  
canonical: https://www.mindstick.com/forum/159073/what-is-the-difference-between-user-and-kernel-modes-in-operating-systems  
category: "Operating System"  
tags: ["operating system"]  
reading_time: 2 minutes  

---

# What is the difference between user and kernel modes in operating systems?

What is the [difference between user](https://www.mindstick.com/forum/483/difference-between-user-created-login-and-system-admin-created-login) and [kernel](https://answers.mindstick.com/qa/96812/what-is-linux-kernel-is-it-legal-to-edit-linux-kernel) modes in [operating systems](https://www.mindstick.com/articles/332551/operating-systems-trends-and-innovations-in-2023)?

## Replies

### Reply by Aryan Kumar

Sure, I can help you with that.

In operating [systems](https://www.mindstick.com/articles/85451/best-travel-systems-for-newborns-to-pick), **[user](https://www.mindstick.com/articles/13001/multi-statement-table-valued-user-defined-function-in-sql-server) mode** and **kernel mode** are two different modes of operation for the central processing unit (CPU). User mode is the default mode for running application programs, while kernel mode is the mode for running the operating system kernel.

The main [difference](https://www.mindstick.com/articles/157114/good-news-or-bad-news-and-the-difference-is) between user mode and kernel mode is the level of access to system resources. In user mode, applications have limited access to system resources, such as memory and hardware devices. In kernel mode, the kernel has full access to all system resources.

This difference in access is important for security reasons. If an application were to crash or be compromised in user mode, it would not be able to access system resources and cause damage to the operating system or the computer. However, if the kernel were to crash or be compromised in kernel mode, it could potentially damage the operating system or the computer.

To protect the kernel from malicious applications, the CPU has a feature called **privileged instructions**. Privileged instructions are instructions that can only be executed in kernel mode. This prevents applications from executing these instructions and gaining unauthorized access to system resources.

When an application needs to access a system resource, it must make a request to the kernel. The kernel will then check the permissions of the application and decide whether to grant the request. If the request is granted, the kernel will execute the privileged instruction on behalf of the application.

The use of user mode and kernel mode provides a layer of security for operating systems. By restricting the access of applications to system resources, it helps to protect the kernel from malicious attacks.

Here is a table summarizing the key differences between user mode and kernel mode:

| Feature | User Mode | Kernel Mode |
| --- | --- | --- |
| Access to system resources | Limited | Full |
| Privileged instructions | Cannot execute | Can execute |
| Security | Less secure | More secure |


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Original Source: https://www.mindstick.com/forum/159073/what-is-the-difference-between-user-and-kernel-modes-in-operating-systems

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