A distribution, or distro, is any packaged collection of software, put together for a particular task. The word distribution, however, is commonly used to refer to a distribution of an operating system which uses Linux as the kernel, and commonly GNU programs as the base operating system. Distributions also include configuration for the software, the layout of the file system hierarchy (see Filesystem Hierarchy Standard), additional software or scripts to maintain the operating system, and repositories for getting more software.
As far as the ordinary user is concerned, the key features of an operating system distribution will include:
- A package manager as well as the packages it can install.
- The desktop environment and applications available.
- Ease of installation, administration and maintenance.
- Ease of use.
- Hardware supported.
Distributions customize various software, so that the distribution feels more integrated. This configuration includes kernel configuration that determines what hardware is supported, as well as how good that distribution is at finding out what hardware is on a system and loading the right kernel modules to make the hardware work. Custom configurations are also seen extensively on the desktop, such as custom backgrounds and themes, and the package manager. Most distributions differ in these regards, especially in the custom configurations.
Distributions are often designed with specific goals and target demographics in mind. Some distributions are designed for Windows users, others for power users, some for running as a server, firewall, or router. Some are designed to be fast, others to be small. Some have good internationalization or accessibility support. Its really mostly about choice.
Obtaining a distribution is fairly easy. Most distributions will have access to free ISO downloads on their websites. Still, can usually buy a CD or DVD from them, as well as a manual. Some distributions can be bought from stores, these come in a box and also include a manual.