Architecture of Linux Operating System

Linux is an open-source UNIX-based operating system. The main component of the Linux operating system is Linux kernel. It is developed to provide low-cost or free operating system service to personal system users, which includes an X-window system, Emacs editor, IP/TCP GUI, etc.

Linux distribution

A Linux system package, known as a distribution, consists of multiple Linux distributions available for different computing needs. Linux distribution is developed using a set of software based on compatibility with the Linux core kernel, using which Linux-based operations in different systems, such as personal systems, embedded systems, etc. There are around 600 distributions available.

Each distribution has specialized packages installed to support specific tasks. This means you can download software related to your field of work using a Linux distribution.

Some Linux distributions are: MX Linux, Manjaro, Linux Mint, elementary, Ubuntu, Debian, Solus, Fedora, openSUSE, Deepin

Components of Linux

Like any operating system, Linux consists of software, computer programs, documentation, and hardware.

The main components of Linux operating system are: Application, Shell, Kernel, Hardware, Utilities

1. Kernel

Kernel is the main core component it is lies between the shell and the hardware. It controls the activity of other hardware components. It visualizes the common hardware resources and provide each process with necessary virtual resources. It makes the process to wait in the ready queue and execute in consequently to avoid any kind of conflict.

The kernel is software that manages communication between the hardware and the system. It cannot directly interact with directories or files. Instead, the kernel handles the communication between the computer system and the hardware.

The kernel is responsible for:

• Memory management: Manages and allocates memory efficiently.
• Resource allocation: Distributes system resources to different processes.
• Device management: Controls input/output devices like printers and scanners.
• Process management: Manages process execution and scheduling.
• Application interaction: Bridges applications with system-level functions.
• Security: Provides essential system-level security.

Different of types of kernel

There are several kernel types

1. Monolithic Kernel

A Monolithic kernel is an operating system kernel where all concurrent processes run simultaneously within the kernel itself, sharing the same memory resources. This type of kernel operates on a step-by-step dependency model, internally managing the various components or scripts an application may rely on to function correctly.

If you’ve ever seen a terminal prompt saying dependencies are being downloaded or destroyed, that’s because the kernel must ensure the right support exists before running the app. This makes Monolithic kernels powerful but also heavy.

2. Micro kernel

In micro kernel user services and kernel services are executed in separate address spaces. User services are kept in user address space and kernel services are kept in kernel address space. This architecture means dependencies are not embedded directly within the kernel, instead, applications must install and manage their own. While this design enhances modularity, it can lead to slower performance as everything relies on external services.

Microkernels are advanced but can be slower because they don’t have dependencies pre-installed like Monolithic kernels do. They're commonly used in systems that prioritize security and modularity.

3. Exokernel

Exo-kernel is designed to manage hardware resources at application level. High level abstraction is used in this operating system to offer hardware resources access to kernel.

4. Hybrid kernel

It is the combination of both monolithic kernel and microkernel. Windows uses a Hybrid Kernel. It supports system-level performance like a Monolithic kernel while offering the modular design of Microkernels.

For example, it includes Microkernel-level readability while managing dependencies internally like a Monolithic kernel. This makes it suitable for tasks like scheduling, performance optimization, and balancing CPU load during video editing, gaming, etc.

Hybrid kernels provide balanced performance without drastically increasing system size. However, they do tend to have slightly larger kernel images—ranging up to 500–600MB.

Main Subsystems of kernel:

• Process scheduler: Responsible for fairly distributing the the processing time among all the concurrently running process.
• Memory management unit: This kernel sub unit is responsible for proper distribution of memory resources among the concurrently running process.
• Virtual file system: This subsystem provides interface to access stored data across different file system and different physical media.

2. System Library

System libraries are some predefined functions by using which any application programs or system utilities can access kernel's features. These libraries are the foundation upon which any software can be built.

Some of the most common system libraries are:

1. GNU C library: This is the C library that provides the most fundamental system for the interface and execution of C programs. This provides may in-built functions for the execution.
2. libpthread (POSIX Threads): This library plays important role for multithreading in Linux, it allows users for creating and managing multiple threads.
3. libdl (Dynamic Linker): This library is responsible for the loading and linking file at the runtime.
4. libm (Math Library): This library provides user with all kind of mathematical function and their execution.

Some other system libraries are: librt (Realtime Library), libcrypt (Cryptographic Library), libnss (Name Service Switch Library), libstdc++ (C++ Standard Library)

3. Shell

The Shell is also software or It can be determined as the interface to the kernel. It takes commands from the user and interprets them. The shell transmits these commands to the kernel, which then performs the requested operations. Users can just enter the commend and using the kernel's function that specific task is performed accordingly.

Different types of shell

Each shell offers unique features and user experiences for interacting with Unix/Linux systems, from basic scripting to advanced customization.

1. Bourne Shell (sh)

The Bourne Shell was one of the first shells in Unix. Think of it as the "basic command helper" that lets you talk to your computer. You could type commands, run simple programs, and even write small scripts to automate tasks. It doesn’t have fancy features, but it’s reliable and still used in scripting today.

2. C Shell (csh)

The C Shell was made to feel more like the C programming language, which many developers already knew. It added cool features like the ability to go back and run previous commands without typing them again. It was great for quick tasks, but not the best for serious scripting jobs.

3. Korn Shell (ksh)

The Korn Shell came later to improve on both the Bourne and C shells. It was powerful, easy to script with, and worked with older scripts too. Big companies used it because it balanced old and new features well. But at first, it wasn’t free, which made it harder for everyone to use.

4. Bash (Bourne Again Shell)

Bash is the most popular shell today. It's like an upgraded version of the Bourne Shell. It lets you use arrow keys to go through old commands, press Tab to auto-complete file names, and run powerful scripts. It’s free and comes by default in most Linux systems and even on Mac computers.

5. Z Shell (zsh)

Z Shell or zsh is super popular with developers. It combines features from all the other shells, looks nice, and is very customizable. It fixes many problems found in older shells and adds fun features like themes and plugins. Mac now uses it by default.

7. Fish (Friendly Interactive Shell)

Fish is made to be super beginner-friendly. It highlights mistakes as you type, suggests commands, and even lets you set things up using a web browser. It’s not the best for big scripts, but perfect if you want something easy and nice to use for everyday work.

4. Hardware Layer

Hardware layer of Linux is the lowest level of operating system track. It is plays a vital role in managing all the hardware components. It includes device drivers, kernel functions, memory management, CPU control, and I/O operations. This layer generalizes hard complexity, by providing an interface for software by assuring proper functionality of all the components.

5. System utility

System utilities are the commend line tools that preforms various tasks provided by user to make system management and administration better. These utilities enables user to perform different tasks, such as file management, system monitoring, network configuration, user management etc.

Conclusion:

The most powerful and versatile component of Linux operating system is Kernel, using which functional of whole operating system can be controlled. Kernel provides a huge range of functionality, which can be easily accessed by the user in an interactive way using shell. For the proper functionality of the operating system, proper hardware are needed. All the components of the the operating system make it easier, faster, stable and reliable.