Kernel and its Types: Explanation with Real-life Analogy

This article covers kernel and its advantages and disadvantages.It also covers user mode and kernel mode. Different types of kernel are also covered. The Kernel is seen as the most important part of your operating system. It’s responsible for managing your system resources, running processes, and communicating with the hardware. The Kernel interacts with devices, allocating memory and handling interrupts and requests from processes running on the computer. 

The Kernel manages resources such as CPU time, disk space, network connections, timers, etc., executes user-level programs at regular intervals (via scheduler), recognizes files when users open them, and intercept certain keystrokes before they are sent to the application program in focus, etc. This post will take a closer look at Kernel and its types. This article also includes user mode and kernel mode.

Table of contents

• What is Kernel in Operating System?
• Functions of a Kernel
• How Does the Kernel Work in Your Operating System?
• Advantages of the Kernel 
• Disadvantages of the Kernel 
• User-mode and Kernel Mode
• Types of Kernel
• Conclusion

What is Kernel?

The Kernel is the heart of your operating system. Kernel handles all operations on behalf of operating system.

A Kernel is an intermediary between applications and hardware. This means that applications can run without knowing or caring about the underlying hardware details. It manages low-level tasks such as disk management, task management, and memory management. Whenever you start a system, Kernel is the first program that is loaded after the bootloader, and it remains in the memory until the operating system is shut-down.

The core component keeps your system running, managing all your software and hardware. Without it, your computer would be a useless pile of metal and plastic.

A kernel must be fast and responsive. It needs to handle all the requests and responses quickly and efficiently. To do this, the Kernel uses a lot of kernel-level memory. This memory is isolated from the main memory of your computer. This means that the Kernel can use it to store data and code without affecting other applications.

NOTE: Kernel can also be changed to improve battery life or to change CPU scheduling.

Also read: Real-time operating system

Also read:Distributed operating system 

Functions of a Kernel

A Kernel in an operating system performs the following functions:

1. Device Management: Processes require various peripheral devices such as a mouse and keyboard connected to the computer to perform various tasks. The Kernel manages the allocation of the peripheral devices.
2. Resource Management: Kernel shares the resources between different processes while ensuring that every process has unfirm access to the resources
3. Memory management: Every process requires some memory to execute. The Kernel allows the processes to access the memory safely. It is responsible for allocating and deallocating memory to processes for their execution.
4. Access Computer Resource: A kernel can access different computer resources such as RAM, CPU, I/O devices, and other resources. Every program needs to access the memory to execute. The Kernel decides which memory each process will use, and the action is taken if memory is unavailable. 

How Does the Kernel Work in Your Operating System?

The Kernel is considered the most crucial part of an operating system.

The Kernel controls everything that goes on in your computer, from launching applications to managing your files. The Kernel is also responsible for security, ensuring unauthorized users can’t access your system.

Take Kernel as the brain of your computer. It’s essential for running your system and keeping it safe. The Kernel calls the hardware device via a system call.

Also explore: What is Operating Systems (OS) – Types, Functions, and Examples

Also explore: Operating system interview questions

Advantages of the Kernel 

• It is responsible for managing the system’s resources, including memory, processors, and devices.
• Provides essential services to users and applications, such as security, multitasking, and communications.
• It handles essential tasks such as suspending or terminating processes when needed.
• It improves performance, better security, and increased stability.

Disadvantages of the Kernel 

The developer should need to consider the particular requirements of the device. But, not all developers are familiar with the specific hardware requirements of each device.

The Kernel can be vulnerable to attacks. If an attacker can exploit a vulnerability in the Kernel, they could gain access to your system and damage or steal your data.

Read: Operating System Online Courses & Certifications

User-mode and Kernel Mode

User Mode

When an application like MS word handling a text editor runs on the operating system, the system is in user mode. The mode bit is 0 in that case. The mode bit will change from 1 to 0 if it switches to kernel mode. The user mode to kernel mode is switched when there is a need to access any device or any interrupt/system call occurs. 

Kernel-mode

When the system boots, the system starts with kernel mode. And the applications are executed in user mode. The switch can happen from user mode to kernel mode when

• Interrupt occurs
• Need to access privileged instruction 
• Need to access any device
• The mode bit is changed from 0 to 1 in case of the system switch back to user mode.

Real-life scenarios

You must have seen the following errors. The Kernel generates these types of errors. When you try to download any file you receive an error message(error-1) that this file can harm your computer. As kernel foresee the problems that can occur if you will download that file or maybe the resources that can be used for that will not be available.

Error-1 

Error-2 

Types of the Kernel

The five main types of kernels are:

• Monolithic Kernel
• Microkernel
• Hybrid Kernel
• Nano Kernel
• Exo Kernel

1. Monolithic Kernel: Monolithic kernels are the simplest and most common type of Kernel. They include the core functionality of the operating system and support all devices connected to it. In this, the user and kernel services are implemented in the same memory space. Due to this, the size of the kernel increases, which in turn increases the size of the operating system. The main benefit is that the process execution is faster as there is no separate memory space for the user and Kernel.
2. Microkernel: Microkernels are a newer development and, as such, are not as common as monolithic kernels. They include only the essential services and devices required for the system to function. This results in a smaller kernel that is faster and uses less memory. Here, the user and kernel services are implemented in two different spaces. It has separate User Space and Kernel Space. This reduces the size of the Kernel and results in reducing the size of the operating system.
3. Hybrid Kernel: Hybrid kernels combine monolithic and microkernels. They include more services than microkernels but less than monolithic kernels. This allows them to offer some of the benefits of both kernels. It borrows speed from the monolithic kernels and modularity from microkernels.
4. Nano Kernel: Nano kernels are the smallest type of Kernel, consisting of only a few thousand lines of code. It means that the code executing in the privileged mode of the hardware is minimal. They are used primarily in embedded systems or devices with limited resources.
5. Exo Kernel: This Kernel has separate resource protection and management. It is suitable for use when performing application-specific customization. Exo kernels are designed for use in mobile devices. They are a variation of microkernels that include additional features specifically for mobile devices, such as power management and support for multiple processors.

Conclusion

The kernel manages the system’s resources and ensures that the different parts of the operating system work together. You can better troubleshoot and optimize your computer’s performance by understanding how the Kernel works. In this article, we saw what is kernel and its types. If you like this article do share it with your friends.

Happy Learning!!!

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