1. Introduction

Linux is Open source software in earlier stages, It has been the most used operating system in the world, the Linux distributions are based on collection of software, based on the package manager the Linux distributions are available, both Open source and commercial Operating systems are available.

The below table shows major distributions that are used

Redhat Based	Debian Based	Gentoo	Slackware
Red Hat Enterprise Linux	Ubuntu
Fedora	Ubuntu Distributions
Open SUSE	Linux Mint
Oracle Linux	Third-party Distributions
Urpmi	Debian Stable
Independent RPM distributions	Knoppix

2. Operating System Family

The below diagram shows the OS distribution family.

There are few other distribution are available, most of them are custom kernel made for particular use. The above are most widely used distribution, based on the kernel OS distribution the Operating system available in the market, both commercial as well as open source. Since the Linux is under the GPL, (General Public License), anybody can take the source code and compile and distribute.

The main advantage is X11 based Graphical User Interface (GUI), it can be used as sever or desktop based operating system. Command Line interface is widely used, give us the full control of the operating system.

3. RPM Based Distribution

RPM Based OS distributions which falls under Redhat are support commercial and open source supports. Usually the packages will have extension .rpm

4. Debian Based Distribution

Debian is free and open source based operating system, it will have extension .deb packages, there are lot of distributions based on Debian, most widely used operating system are Ubuntu, Linux Mint.

5. Other Distributions

Gentoo is a compiled according to the user requirement, and Slackware is one of the oldest distribution in Linux, initially used in Suse Linux.

Operating System Architecture table

	x86_64	ARM 64	IBM Z	IBM Power System	IA-32(i386)
Redhat	Yes	Yes	Yes	Yes
Debian	Yes	Yes
Slackware	Yes	Yes			Yes
Gentoo	Yes			Yes	Yes

x86_64 is a 64 bit x86 architecture based on Intel, along with new 4-level paging and compatibility mode.

ARM – Advanced RISC Machine Processors that have a RISC architecture typically require lesser number of transistors, which advantage in cost reduction, less power consumption and heat.

IBM Power microprocessors – Named as “Performance Optimization With Enhanced RISC”

IA-32 is the 32 bit x86 architecture, it was the defined by Intel, also known as 80386 microprocessor. There are few other architecture available in the market like SPARC.

6. Top 10 OS distribution

The below table is top 10 OS distribution based on distrowatch.com on May 2020

Rank	Distribution
1	MX Linux
2	Manjaro
3	Linux Mint
4	Ubuntu
5	Elemantary
6	Debian
7	Solus
8	KDE neon
9	POP!_OS
10	Fedora

7. Linux Distributions that runs on RAM

There are few linux distributions we can run on RAM, check the links below and try it

Tiny Core Linux – 11MB – http://tinycorelinux.net/

SliTaz – 40 MB – http://slitaz.org/en/

Damm Small linux is a 50 MB Linux os distribution, we can run a GUI based live operating system

DSL link – http://www.damnsmalllinux.org/

8. Live CD / USB

Some notable Live USB or CD based Linux Operating system

Core OS
Knoppix
Parted Magic
PC LinuxOS
Puppy Linux

Current Linux running on Redhat, Debian, SLES based OS family
Other Operating system families are Windows, Sun Solaris, MacOSX, HP-UX, AIX, BSD, Alpine and ArchLinux
Linux operating is used in Server, Desktop, mobile, cloud computing, embedded devices, mainframe computers, super computers.

Linux desktop environments are GNOME ,KDEPlasma , GNOME ,MATE ,Cinnamon , LXDE, Pantheon and Xfce

Useful Links

Operating System : https://en.wikipedia.org/wiki/Operating_system
Redhat OS : https://www.redhat.com/en
Oracle Linux: https://www.oracle.com/linux/technologies/oracle-linux-downloads.html
Debian: https://www.debian.org/distrib/
CentOS: https://www.centos.org/download/
LinuxMint: https://www.linuxmint.com/
Ubuntu: https://ubuntu.com/download
GNU : https://www.gnu.org/
Linux Distribution in One Page https://distrowatch.com
Under GPL License Linux is free to use, distribute. Refer for more info https://en.wikipedia.org/wiki/GNU_General_Public_License