What is a Monolithic Kernel?
A monolithic kernel is an operating system architecture where the entire operating system works in kernel space. It is a very basic operating system which performs tasks like file management, device management, memory management, and process management. All these processes are directly controlled within the kernel. This also manages resources between hardware and application along with User service and kernel services that are implemented under the same address space. It also increases the size of the kernel and thus increases the size of the operating system as well. This kernel was one of the most used and preferred OS architecture of the late 1980s and many operating systems have built upon this.
Operating systems such as Linux, Solaris, AIX, OpenVMS, HP-UX, DOS, etc leverages Monolithic Kernel OS architecture.
Below is the architecture diagram of a Monolithic Kernel, as you can see the IPC, file system, device drivers, etc is working in the kernel space and thus have a larger kernel than Microkernel and hybrid kernel OS.
To understand any operating system it’s very important to understand the architecture of the OS and the different components and how do they communicate with each other. As you can see from the architecture diagram shown above, the monolithic kernel is a very old and basic operating system that perform tasks like batch processing, file transfer, etc. it works as a virtual machine and takes control over all the hardware components.
Key things to notice in Monolithic kernel architecture is
- All the hardware components which are needed for processing is embedded inside the kernel.
- Since all the components are present inside the kernel, they can communicate with each other directly and also with the kernel.
- It can handle very limited resources and are ideal for performing smaller tasks.
- It can load modules dynamically, dynamically loadable modules incur a very small overhead as compared to build the module into the operating system image.
- It also helps to keep the amount of code running in kernel space to a minimum.
How does the monolithic kernel make working so easy?
This kernel has a very simple architecture and that makes it so easy to work and understand. It also requires less code to write a monolithic kernel than other kernels like Microkernel. monolithic kernel leverages one address space running in kernel mode for its functioning with all of the kernel and device drivers. The main advantage of this approach is effective especially with the x86 architecture was switching a task is an expensive operation.
Graphical overview of Monolithic Kernel
What can you do with Monolithic Kernel?
It offers high speed and is ideal for smaller tasks as it can handle limited resources. With a monolithic kernel, you can perform tasks like CPU scheduling, file management, memory management, and other functions via system calls.
So far we have seen the architecture of the Monolithic kernel and what it can do, now let’s see the advantages:
- The execution speed is faster in the monolithic kernel as compared to the microkernel.
- Less coding is required to write this kernel as compared to the microkernel.
- It is one single piece of software and thereby both source and compiled code is smaller.
- Monolithic Kernel consists the core functions of the operating system and device drivers and capable of loading modules at runtime.
- Also loading the modules dynamically helps to keep the amount of code running in the kernel to a minimum.
Why should we use Monolithic Kernel?
Use this kernel when you need the execution to be fast and fewer resources need to be handled. Also if modules need to be load dynamically one can go with the Monolithic kernel OS, dynamic loading of modules is a more flexible way of handling the operating system image at runtime as compare to rebooting operating system image.
This OS has a very confined scope as it was only capable of performing smaller tasks. Also, there are certain limitations of Monolithic kernel OS that you should be well aware of while making a decision on the OS.
- This kernel is hard to extend.
- If any service crashes the whole system can get crashed in a monolithic kernel. This is the major drawback of Monolithic kernel.
- Coding in kernel space is hard as you can not make use of common libraries and debug is also hard.
- If a user wants to add a new service then the entire operating system has to be modified.
Who is the right audience for learning Monolithic Kernel technologies?
For any computer science graduate or IT professionals who have just started the career, this could be a good read. Having a good knowledge of OS is always an add on for the company. This kernel has a very simple architecture its very easy to understand and work on it. Also, an understanding of monolithic kernel is a must for understanding a more advanced operating system like Microkernel operating system and hybrid operating system.
How this technology will help you in career growth?
Having a good knowledge of any operating system is an added advantage for any IT professionals, also this is a good starting point to understand a kernel based operating system. Most of the banking and financial projects still make use of Linux and Unix based operating system and since they have this kernel architecture it would be great to have a good understanding of kernel architecture in depth.
We have reached to the end of the article, hope you guys now have a clear understanding of what Monolithic kernel is, how does it work, its architecture and how can it help you to excel in your career. Also if you get the clarity on the Monolithic kernel OS architecture it will be easy for you to understand the more advanced OS like microkernel OS and Hybrid kernel OS architecture.
This has been a guide to Monolithic Kernel. Here we discussed the basic concepts, Definition, scope, career growth and advantages of Monolithic Kernel. You can also go through our other suggested articles to learn more –