Linux development and major distributions
Linux is a clone of the operating system Unix, written from scratch in 1991 as a hobby project by Linus Torvalds. He made the source code freely available across the Internet and others joined. Despite adopting all the UNIX specification, Linux really isn't UNIX. It's just UNIX-like. Linux means the kernel of the system, which is a component in a working Linux system. A complete Linux system is called a distribution of Linux. There are numerous distributions; some are general-purpose, and some are optimized for specific uses.
Debian was begun in August 1993 by Ian Murdock, as a new distribution. It started as a small group, and gradually grew to become a large, well-organized community of developers and users. Debian is pronounced /'de.bi.ən/. It comes from the names of the creator of Debian, Ian Murdock, and his wife, Debra. Ubuntu is the most popular Debian derived distribution. In 2004, Mark Shuttleworth gathered a small team of Debian developers who together founded Canonical and created Ubuntu. Ubuntu was the first operating system to commit to scheduled releases. This is the origin of the term LTS for stable, maintained releases. LTS or "Long Term Support" releases are published every two years.
CentOS is a community-supported Linux distribution derived from the sources of Red Hat Enterprise Linux (RHEL) freely provided to the public by Red Hat. CentOS project mainly change packages to remove trademarked vendor branding and artwork. CentOS aims to be functionally compatible with RHEL, but do not offer the paid support that Red Hat does. Red Hat started out as a simple distribution, then named "Red Hat Linux". Red Hat curates, secures, and supports a Linux distribution known as Red Hat Enterprise Linux. Red Hat Enterprise Linux is the world's leading enterprise Linux platform. openSUSE is a distribution that is independent of but sponsored by SUSE company. It incorporates many aspects of Red Hat. The major openSUSE releases are Leap, which shares a common codebase with all SUSE Linux Enterprise packages, and Tumbleweed, a rolling-release distribution.
Linux Mint is one of the most popular desktop Linux distributions. It works out of the box, with full multimedia support and is extremely easy to use. It's community-driven, based on Debian and Ubuntu. Scientific Linux is a rebuild of Red Hat Enterprise Linux sponsored by Fermilab. Primary user base is within experimental facilities for scientific computing needs. In April 2019, it was announced that Scientific Linux would be discontinued.
Raspberry Pi is a computer with a keyboard and mouse that plugs into display or TV. Raspberry Pi is used to learn coding and to build electronics projects, and for many of the things that desktop PC does, like browsing the internet, playing games and videos. Raspbian is the recommended operating system for normal use on a Raspberry Pi. Raspbian is a free operating system based on Debian, optimised for the Raspberry Pi hardware.
Android, sponsored by Google, is a bundle of Linux and the software necessary to run a phone or tablet. Android is one of the mobile market leaders.