ABOUT LINUX DISTRIBUTIONS

Distribution

Free software projects, although developed in a collaborative fashion, are often produced independently of each other. However, given that the software licenses explicitly permit redistribution, this provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution.

A Linux distribution, commonly called a "distro", is a project that manages a remote collection of Linux-based software, and facilitates installation of a Linux operating system. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. They include system software and application software in the form of packages, and distribution-specific software for initial system installation and configuration as well as later package upgrades and installs. A distribution is responsible for the default configuration of installed Linux systems, system security, and more generally integration of the different software packages into a coherent whole.

A typical general purpose distribution includes the following:

1. A boot loader: A piece of software that can be loaded by the systems firmware (bios in the case of a PC) and then perform the actions needed to load and start the linux kernel. Often a menu is presented that will allow the user to select which operating system to load. The most common bootloaders for the PC architecture are LILO or GRUB.
2. The Linux kernel: The core or heart of the operating system. The name of the OS comes from here.
3. Boot scripts, disk/storage maintenance tools, authentication tools, and scripting languages: They are administration tools, usually considered part of the operating system.
4. GNU C Library and, optionally, the GNU Compiler Collection: The development tools, used to assist or develop applications.
5. GNU bash shell, X Window System networking and display protocol and an accompanying desktop environment such as KDE, GNOME,or Xfce: The shells and graphic systems, used for interacting with the user.
6. Application software packages: There are hundreds of them in most distributions (thousands in bigger distributions, like Gentoo, Fedora, Debian, etc.) , from office suites to webservers to media players to 3D computer graphics software to text editors, and scientific programs. They may come in some storage medium, like a DVD, or, more commonly, be available in on-line repositories.
7. Package management software: These are created specifically for the distribution, for organizing all software, seamless downloading and installing, upgrading and managing security issues.

As well as those designed for general purpose use, distributions may be specialized for different purposes including: computer architecture support, embedded systems, stability, security, localization to a specific region or language, targeting of specific user groups, support for real-time applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only free software. Currently, over three hundred distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.