- Operating System — Linux
- Operating System
- Essentials of Unix Operating System
- CREATE your OWN Operating System from SCRATCH
- Components of Linux System
- Kernel Mode vs User Mode
- Basic Features
- What is Linux Operating System? Introduction to Linux OS
- What is Linux?
- Why do you need an OS?
- Who created Linux?
- History of Linux
- Linux gets its due attention
- Benefits of Linux
- Is it for me?
- Then Why Linux?
- What is Linux?
- What is Linux?
- Why use Linux?
- Open source
- What is a “distribution?”
- Which distribution is right for you?
- Installing Linux
- Installing software on Linux
- More resources
Operating System — Linux
86 Lectures 10 hours
Essentials of Unix Operating System
5 Lectures 4.5 hours
CREATE your OWN Operating System from SCRATCH
8 Lectures 43 mins
Linux is one of popular version of UNIX operating System. It is open source as its source code is freely available. It is free to use. Linux was designed considering UNIX compatibility. Its functionality list is quite similar to that of UNIX.
Components of Linux System
Linux Operating System has primarily three components
Kernel − Kernel is the core part of Linux. It is responsible for all major activities of this operating system. It consists of various modules and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs.
System Library − System libraries are special functions or programs using which application programs or system utilities accesses Kernel’s features. These libraries implement most of the functionalities of the operating system and do not requires kernel module’s code access rights.
System Utility − System Utility programs are responsible to do specialized, individual level tasks.
Kernel Mode vs User Mode
Kernel component code executes in a special privileged mode called kernel mode with full access to all resources of the computer. This code represents a single process, executes in single address space and do not require any context switch and hence is very efficient and fast. Kernel runs each processes and provides system services to processes, provides protected access to hardware to processes.
Support code which is not required to run in kernel mode is in System Library. User programs and other system programs works in User Mode which has no access to system hardware and kernel code. User programs/ utilities use System libraries to access Kernel functions to get system’s low level tasks.
Following are some of the important features of Linux Operating System.
Portable − Portability means software can works on different types of hardware in same way. Linux kernel and application programs supports their installation on any kind of hardware platform.
Open Source − Linux source code is freely available and it is community based development project. Multiple teams work in collaboration to enhance the capability of Linux operating system and it is continuously evolving.
Multi-User − Linux is a multiuser system means multiple users can access system resources like memory/ ram/ application programs at same time.
Multiprogramming − Linux is a multiprogramming system means multiple applications can run at same time.
Hierarchical File System − Linux provides a standard file structure in which system files/ user files are arranged.
Shell − Linux provides a special interpreter program which can be used to execute commands of the operating system. It can be used to do various types of operations, call application programs. etc.
Security − Linux provides user security using authentication features like password protection/ controlled access to specific files/ encryption of data.
The following illustration shows the architecture of a Linux system −
The architecture of a Linux System consists of the following layers −
Hardware layer − Hardware consists of all peripheral devices (RAM/ HDD/ CPU etc).
Kernel − It is the core component of Operating System, interacts directly with hardware, provides low level services to upper layer components.
Shell − An interface to kernel, hiding complexity of kernel’s functions from users. The shell takes commands from the user and executes kernel’s functions.
Utilities − Utility programs that provide the user most of the functionalities of an operating systems.
What is Linux Operating System? Introduction to Linux OS
Updated October 8, 2022
What is Linux?
LINUX is an operating system or a kernel distributed under an open-source license. Its functionality list is quite like UNIX. The kernel is a program at the heart of the Linux operating system that takes care of fundamental stuff, like letting hardware communicate with software.
In this Linux tutorial, you will learn –
Why do you need an OS?
Every time you switch on your computer, you see a screen where you can perform different activities like write, browse the internet or watch a video. What is it that makes the computer hardware work like that? How does the processor on your computer know that you are asking it to run a mp3 file?
Well, it is the operating system or the kernel which does this work. So, to work on your computer, you need an Operating System (OS). In fact, you are using one as you read this on your computer. Now, you may have used popular OS’s like Windows, Apple OS X, but here we will learn introduction to Linux operating system, Linux overview and what benefits it offers over other OS choices.
Who created Linux?
Linux is an operating system or a kernel which germinated as an idea in the mind of young and bright Linus Torvalds when he was a computer science student. He used to work on the UNIX OS (proprietary software) and thought that it needed improvements.
However, when his suggestions were rejected by the designers of UNIX, he thought of launching an OS which will be receptive to changes, modifications suggested by its users.
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History of Linux
So Linus devised a Kernel named Linux in 1991. Though he would need programs like File Manager, Document Editors, Audio -Video programs to run on it. Something as you have a cone but no ice-cream on top.
As time passed by, he collaborated with other programmers in places like MIT and applications for Linux started to appear. So around 1991, a working Linux operating system with some applications was officially launched, and this was the start of one of the most loved and open-source OS options available today.
The earlier versions of Linux OS were not so user-friendly as they were in use by computer programmers and Linus Torvalds never had it in mind to commercialize his product.
This definitely curbed the Linux’s popularity as other commercially oriented Operating System Windows got famous. Nonetheless, the open-source aspect of the Linux operating system made it more robust.
Linux gets its due attention
The main advantage of Linux was that programmers were able to use the Linux Kernel to design their own custom operating systems. With time, a new range of user-friendly OS’s stormed the computer world. Now, Linux is one of the most popular and widely used Kernel, and it is the backbone of popular operating systems like Debian, Knoppix, Ubuntu, and Fedora. Nevertheless, the list does not end here as there are thousands of Best versions of Linux OS based on the Linux Kernel available which offer a variety of functions to the users.
Linux Kernel is normally used in combination of GNU project by Dr. Richard Stallman. All mordern distributions of Linux are actually distributions of Linux/GNU
Benefits of Linux
Linux OS now enjoys popularity at its prime, and it’s famous among programmers as well as regular computer users around the world. Its main benefits are –
It offers a free operating system. You do not have to shell hundreds of dollars to get the OS like Windows!
- Being open-source, anyone with programming knowledge can modify it.
- It is easy to learn Linux for beginners
- The Linux operating systems now offer millions of programs/applications and Linux softwares to choose from, most of them are free!
- Once you have Linux installed you no longer need an antivirus! Linux is a highly secure system. More so, there is a global development community constantly looking at ways to enhance its security. With each upgrade, the OS becomes more secure and robust
- Linux freeware is the OS of choice for Server environments due to its stability and reliability (Mega-companies like Amazon, Facebook, and Google use Linux for their Servers). A Linux based server could run non-stop without a reboot for years on end.
Is it for me?
Users, who are new to Linux, usually shun it by falsely considering it as a difficult and technical OS to operate but, to state the truth, in the last few years Linux operating systems have become a lot more user-friendly than their counterparts like Windows, so trying them is the best way to know whether Linux suits you or not.
There are thousands of Best Linux OSs and Linux softwares available based on the Linux Kernel; most of them offer state-of-the-art security and applications, all of it for free!
This is what Linux is all about, and now we will move on to how to install Linux and which Distribution you should choose.
Then Why Linux?
UNIX is called the mother of operating systems which laid out the foundation to Linux. Unix is designed mainly for mainframes and is in enterprises and universities. While Linux is fast becoming a household name for computer users, developers, and server environment. You may have to pay for a Unix kernel while in Linux it is free.
But, the commands used on both the operating systems are usually the same. There is not much difference between UNIX and Linux. Though they might seem different, at the core, they are essentially the same. Since Linux is a clone of UNIX. So learning one is same as learning another.
What is Linux?
Looking to get started in Linux? Develop a good working knowledge of Linux using both the graphical interface and command line across the major Linux distribution families with The Linux Foundation’s Intro to Linux online course. Enroll for free here. (Este curso también está disponible en español. Haga clic aquí para Introducción a Linux.)
From smartphones to cars, supercomputers and home appliances, home desktops to enterprise servers, the Linux operating system is everywhere.
Linux has been around since the mid-1990s and has since reached a user-base that spans the globe. Linux is actually everywhere: It’s in your phones, your thermostats, in your cars, refrigerators, Roku devices, and televisions. It also runs most of the Internet, all of the world’s top 500 supercomputers, and the world’s stock exchanges.
But besides being the platform of choice to run desktops, servers, and embedded systems across the globe, Linux is one of the most reliable, secure and worry-free operating systems available.
Here is all the information you need to get up to speed on the Linux platform.
What is Linux?
Just like Windows, iOS, and Mac OS, Linux is an operating system. In fact, one of the most popular platforms on the planet, Android, is powered by the Linux operating system. An operating system is software that manages all of the hardware resources associated with your desktop or laptop. To put it simply, the operating system manages the communication between your software and your hardware. Without the operating system (OS), the software wouldn’t function.
The Linux operating system comprises several different pieces:
- Bootloader – The software that manages the boot process of your computer. For most users, this will simply be a splash screen that pops up and eventually goes away to boot into the operating system.
- Kernel – This is the one piece of the whole that is actually called ‘Linux’. The kernel is the core of the system and manages the CPU, memory, and peripheral devices. The kernel is the lowest level of the OS.
- Init system – This is a sub-system that bootstraps the user space and is charged with controlling daemons. One of the most widely used init systems is systemd, which also happens to be one of the most controversial. It is the init system that manages the boot process, once the initial booting is handed over from the bootloader (i.e., GRUB or GRand Unified Bootloader).
- Daemons – These are background services (printing, sound, scheduling, etc.) that either start up during boot or after you log into the desktop.
- Graphical server – This is the sub-system that displays the graphics on your monitor. It is commonly referred to as the X server or just X.
- Desktop environment – This is the piece that the users actually interact with. There are many desktop environments to choose from (GNOME, Cinnamon, Mate, Pantheon, Enlightenment, KDE, Xfce, etc.). Each desktop environment includes built-in applications (such as file managers, configuration tools, web browsers, and games).
- Applications – Desktop environments do not offer the full array of apps. Just like Windows and macOS, Linux offers thousands upon thousands of high-quality software titles that can be easily found and installed. Most modern Linux distributions (more on this below) include App Store-like tools that centralize and simplify application installation. For example, Ubuntu Linux has the Ubuntu Software Center (a rebrand of GNOME Software) which allows you to quickly search among the thousands of apps and install them from one centralized location.
Why use Linux?
This is the one question that most people ask. Why bother learning a completely different computing environment, when the operating system that ships with most desktops, laptops, and servers works just fine?
To answer that question, I would pose another question. Does that operating system you’re currently using really work “just fine”? Or, do you find yourself battling obstacles like viruses, malware, slow downs, crashes, costly repairs, and licensing fees?
If you struggle with the above, Linux might be the perfect platform for you. Linux has evolved into one of the most reliable computer ecosystems on the planet. Combine that reliability with zero cost of entry and you have the perfect solution for a desktop platform.
That’s right, zero cost of entry… as in free. You can install Linux on as many computers as you like without paying a cent for software or server licensing.
Let’s take a look at the cost of a Linux server in comparison to Windows Server 2016. The price of the Windows Server 2016 Standard edition is $882.00 USD (purchased directly from Microsoft). That doesn’t include Client Access License (CALs) and licenses for other software you may need to run (such as a database, a web server, mail server, etc.). For example, a single user CAL, for Windows Server 2016, costs $38.00. If you need to add 10 users, for example, that’s $388.00 more dollars for server software licensing. With the Linux server, it’s all free and easy to install. In fact, installing a full-blown web server (that includes a database server), is just a few clicks or commands away (take a look at Easy LAMP Server Installation to get an idea how simple it can be).
If zero cost isn’t enough to win you over–what about having an operating system that will work, trouble free, for as long as you use it? I’ve used Linux for nearly 20 years (as both a desktop and server platform) and have not had any issues with ransomware, malware, or viruses. Linux is generally far less vulnerable to such attacks. As for server reboots, they’re only necessary if the kernel is updated. It is not out of the ordinary for a Linux server to go years without being rebooted. If you follow the regular recommended updates, stability and dependability are practically assured.
Linux is also distributed under an open source license. Open source follows these key tenets:
- The freedom to run the program, for any purpose.
- The freedom to study how the program works, and change it to make it do what you wish.
- The freedom to redistribute copies so you can help your neighbor.
- The freedom to distribute copies of your modified versions to others.
These points are crucial to understanding the community that works together to create the Linux platform. Without a doubt, Linux is an operating system that is “by the people, for the people”. These tenets are also a main factor in why many people choose Linux. It’s about freedom and freedom of use and freedom of choice.
What is a “distribution?”
Linux has a number of different versions to suit any type of user. From new users to hard-core users, you’ll find a “flavor” of Linux to match your needs. These versions are called distributions (or, in the short form, “distros”). Nearly every distribution of Linux can be downloaded for free, burned onto disk (or USB thumb drive), and installed (on as many machines as you like).
Popular Linux distributions include:
- LINUX MINT
- ELEMENTARY OS
Each distribution has a different take on the desktop. Some opt for very modern user interfaces (such as GNOME and Elementary OS’s Pantheon), whereas others stick with a more traditional desktop environment (openSUSE uses KDE).
You can check out the top 100 distributions on the Distrowatch.
And don’t think the server has been left behind. For this arena, you can turn to:
- Red Hat Enterprise Linux
- Ubuntu Server
- SUSE Enterprise Linux
Some of the above server distributions are free (such as Ubuntu Server and CentOS) and some have an associated price (such as Red Hat Enterprise Linux and SUSE Enterprise Linux). Those with an associated price also include support.
Which distribution is right for you?
Which distribution you use will depend on the answer to three simple questions:
- How skilled of a computer user are you?
- Do you prefer a modern or a standard desktop interface?
- Server or desktop?
If your computer skills are fairly basic, you’ll want to stick with a newbie-friendly distribution such as Linux Mint, Ubuntu (Figure 3), Elementary OS or Deepin. If your skill set extends into the above-average range, you could go with a distribution like Debian or Fedora. If, however, you’ve pretty much mastered the craft of computer and system administration, use a distribution like Gentoo. If you really want a challenge, you can build your very own Linux distribution, with the help of Linux From Scratch.
If you’re looking for a server-only distribution, you will also want to decide if you need a desktop interface, or if you want to do this via command-line only. The Ubuntu Server does not install a GUI interface. This means two things your server won’t be bogged down loading graphics and you’ll need to have a solid understanding of the Linux command line. However, you can install a GUI package on top of the Ubuntu Server with a single command like sudo apt-get install ubuntu-desktop. System administrators will also want to view a distribution with regards to features. Do you want a server-specific distribution that will offer you, out of the box, everything you need for your server? If so, CentOS might be the best choice. Or, do you want to take a desktop distribution and add the pieces as you need them? If so, Debian or Ubuntu Linux might serve you well.
For many people, the idea of installing an operating system might seem like a very daunting task. Believe it or not, Linux offers one of the easiest installations of all operating systems. In fact, most versions of Linux offer what is called a Live distribution, which means you run the operating system from either a CD/DVD or USB flash drive without making any changes to your hard drive. You get the full functionality without having to commit to the installation. Once you’ve tried it out, and decided you wanted to use it, you simply double-click the “Install” icon and walk through the simple installation wizard.
Typically, the installation wizards walk you through the process with the following steps (We’ll illustrate the installation of Ubuntu Linux):
- Preparation: Make sure your machine meets the requirements for installation. This also may ask you if you want to install third-party software (such as plugins for MP3 playback, video codecs, and more).
- Wireless setup (if necessary): If you are using a laptop (or machine with wireless), you’ll need to connect to the network, in order to download third-party software and updates.
- Hard drive allocation (Figure 4): This step allows you to select how you want the operating system to be installed. Are you going to install Linux alongside another operating system (called “dual booting”), use the entire hard drive, upgrade an existing Linux installation, or install over an existing version of Linux.
- Location: Select your location from the map.
- Keyboard layout: Select the keyboard for your system.
- User setup: Set up your username and password.
That’s it. Once the system has completed the installation, reboot and you’re ready to go. For a more in-depth guide to installing Linux, take a look at “How to Install and Try Linux the Absolutely Easiest and Safest Way” or download the Linux Foundation’s PDF guide for Linux installation.
Installing software on Linux
Just as the operating system itself is easy to install, so too are applications. Most modern Linux distributions include what most would consider an app store. This is a centralized location where software can be searched and installed. Ubuntu Linux (and many other distributions) rely on GNOME Software, Elementary OS has the AppCenter, Deepin has the Deepin Software Center, openSUSE has their AppStore, and some distributions rely on Synaptic.
Regardless of the name, each of these tools do the same thing: a central place to search for and install Linux software. Of course, these pieces of software depend upon the presence of a GUI. For GUI-less servers, you will have to depend upon the command-line interface for installation.
Let’s look at two different tools to illustrate how easy even the command line installation can be. Our examples are for Debian-based distributions and Fedora-based distributions. The Debian-based distros will use the apt-get tool for installing software and Fedora-based distros will require the use of the yum tool. Both work very similarly. We’ll illustrate using the apt-get command. Let’s say you want to install the wget tool (which is a handy tool used to download files from the command line). To install this using apt-get, the command would like like this:
The sudo command is added because you need super user privileges in order to install software. Similarly, to install the same software on a Fedora-based distribution, you would first su to the super user (literally issue the command su and enter the root password), and issue this command:
That’s all there is to installing software on a Linux machine. It’s not nearly as challenging as you might think. Still in doubt? Recall the Easy Lamp Server Installation from earlier. With a single command:
You can install a complete LAMP (Linux Apache MySQL PHP) server on either a server or desktop distribution. It really is that easy.
If you’re looking for one of the most reliable, secure, and dependable platforms for both the desktop and the server, look no further than one of the many Linux distributions. With Linux you can assure your desktops will be free of trouble, your servers up, and your support requests minimal.
For more information to help guide you through your lifetime with Linux, check out the following resources: