1. Introduction
The kernel is the central component of the OS (operating system). As a result, it has control over system resources and facilitates interactions between hardware and software. Further, it’s a crucial component that maintains the proper functioning of the entire system. In particular, it oversees the management of hardware and processes, file handling, and various other functions.
Additionally, there are five types of kernels, which include:
- Microkernel
- Monolithic kernel
- Hybrid kernel
- Exokernel
Nanokernel
In this tutorial, we’ll learn about Microkernel and Monolithic kernel. Further, we’ll look at the advantages and disadvantages of these kernels. Finally, we’ll cover the differences between the Microkernel and Monolithic kernel.
2. What Is a Microkernel
The microkernel allows for the customization of the OS. It’s broken down into separate processes called servers.
Further, these servers invoke services from each other by sending messages via IPC (Interprocess Communication). The user and kernel services are implemented in different address spaces in the microkernel. In particular, the user services are stored in user space, and the kernel services are stored under kernel address space. Furthermore, the microkernel supports OS functions such as file systems, virtual memory managers, and CPU schedulers.
Overall, microkernel-based OSs offer a high level of extensibility. Examples of microkernel-based OSs include Mac OS X and Windows NT.
2.1. Advantages
The advantages of microkernel include the following:
- The architecture is compact and segregated, potentially leading to improved performance
- Microkernel systems employ a versatile approach where multiple servers can coexist, implementing various APIs
- Adding applications to the system is simplified without disrupting the kernel
- The modularity allows for the modification, reloading, or replacement of several modules without altering the kernel itself
- The system can incorporate new features without requiring recompilation
Now that we’ve known the advantages of microkernels, let’s explore their disadvantages.
2.2. Disadvantages
Despite the wealth of advantages of microkernel, it has its disadvantages:
- The services of the microkernel are relatively expensive microkernel system
- The microkernel system’s performance might vary and cause issues
- In the microkernel, a context switch is necessary when running drivers as processes
We’ve understood the microkernel, with its advantages and disadvantages, in detail. Now, let’s explore the monolithic kernel.
3. What Is a Monolithic Kernel
A monolithic kernel is a large process running entirely in a single address space. In particular, It’s a single static binary file. It manages system resources between the system application and system hardware. Unlike the microkernel, both the user and kernel services run in the same address space.
Furthermore, the monolithic kernel offers file management, process management, CPU scheduling, and other OS services through system calls. Examples of monolithic kernel-based OSs include Unix and Linux.
3.1. Advantages
The advantages of microkernel include the following:
- The structures of the monolithic kernel are easy and simple. It contains all the components required for processing
- Monolithic kernel system runs very quickly due to memory management, process scheduling, file management, etc
- A monolithic kernel operates as a solitary, extensive process confined within a single address space
Now that we know the advantages of monolithic kernels, let’s explore their disadvantages.
3.2. Disadvantages
Just like the microkernel, the monolithic kernel also has disadvantages:
- It’s not scalable. That is, if any system fails, the entire system crashes
- If a user wants to add a new service, they must modify the entire operating system
- Porting code written in the monolithic operating system isn’t a simple task
We’ve seen the major advantages and disadvantages of both microkernel and monolithic kernels. Now, let’s proceed with the differences between them.
4. Main Differences Between Microkernel and Monolithic Kernel
When comparing microkernel and monolithic kernel architectures, several key differences emerge:
Parameters
Microkernel
Monolithic kernel
Size
It’s smaller in size
It’s bigger
Maintainability
It’s easily maintainable
Maintenance requires extra time and resources
Code
It requires more code
Less code is required
Design and Implementation
The system is complex to design
it’s relatively easy to design and implement
Services
Offers IPC and low-level device management services
It contains all OS’s services
Processing speed
Execution speed is low
Execution speed is high
Communication
IPC is implemented using messaging queues
IPC is implemented using signals and sockets
Debugging
Debugging is simple
Debugging is complex and difficult
Functionality
It’s easy to add new functionalities
It’s difficult to add new functionalities
Address Space
User services and kernel services are kept in separate address space
Both user services and kernel services are kept in the same address space
Stability
If one component fails, it doesn’t affect the working of the microkernel
It’s not stable. If one component fails, the entire system crashes
Example
Symbian, L4Linux, Mac OS X, HURD
Linux, BSDs, Solaris, DOS, OpenVMS
This table explains the main differences between microkernels and monolithic kernels.
5. Conclusion
In this article, we’ve explored the characteristics, advantages, and disadvantages of both microkernel and monolithic kernel architectures. Furthermore, we’ve understood the main differences between these two kernels.
Ultimately, the choice between microkernel and monolithic kernel architectures depends on factors such as system requirements, performance considerations, and development priorities.