Jump to content

Linux distribution: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Line 76: Line 76:


== See also ==
== See also ==
{{portalpar|Free software}}
{{portalpar|Free software|Floss draft.png}}
*[[Comparison of Linux distributions]]
*[[Comparison of Linux distributions]]
*[[Cygwin]]
*[[Cygwin]]

Revision as of 16:21, 25 August 2006

A Linux distribution[1] is a version of a Unix-like operating system for computers comprising most of the GNU operating system (excluding GNU Hurd), the Linux kernel, and other assorted programs.

Commercially backed distributions such as Ubuntu (backed by Canonical Ltd.), SUSE Linux (backed by Novell) and Mandriva Linux, and community projects such as Debian and Gentoo, assemble and test the software before releasing their distribution. There are currently over three hundred Linux distribution projects in active development, revising and improving their respective distributions.

History

Before the first Linux distributions, a would-be Linux user was required to be something of a Unix expert, not only knowing what libraries and executables were needed to successfully get the system to boot and run, but also important details concerning configuration and placement of files in the system.

Linux distributions began to appear soon after the Linux kernel was first used by individuals outside the original Linux programmers. They were more interested in developing the operating system than in application programs, the user interface, or convenient packaging.

Early distributions included:

None of these distributions were well-maintained, so Patrick Volkerding released a distribution based on SLS, which he called Slackware; released July 16, 1993 [2], this is the oldest distribution still in active development.

Linux distributions attracted users as an alternative to the DOS and Microsoft Windows operating systems on the PC, Mac OS on the Apple Macintosh and proprietary versions of Unix. Most early adopters were used to Unix from work or school. They embraced Linux for its stability, low (if any) cost, and for the inclusion of the source code for most or all of the software included.

The distributions were originally simply a convenience, but today they have become the usual resort even for Unix or Linux gurus. To date, Linux has proven more popular in the server market, primarily for Web and database servers (see also LAMP), than in the desktop market.

Components

A typical Linux distribution comprises a Linux kernel, GNU tools and libraries, additional software, documentation, a window system, window manager, and a desktop environment. Most of the included software is free software/open-source software which is distributed by its maintainers both as pre-compiled binaries and in source code form, allowing users to modify and compile the original source code if they wish. Other software included with some distributions may be proprietary and may not be available in source code form.

Many provide an installation system akin to that provided with other modern operating systems. Self-hosting distributions like Gentoo Linux and Linux From Scratch provide the source code of all software and include binaries only of a basic kernel, compilation tools, and an installer; the installer compiles all the software for the specific microarchitecture of the user's machine.

Package management

See also: Package management system and Linux package formats

Distributions are normally segmented into packages, each package holding a specific application or service; examples of packages include a library for handling the PNG image format, a collection of fonts, or a web browser.

The package is typically provided as compiled code with installation and removal of packages handled by a package management system (PMS) rather than a simple file archiver. Each package intended for such a PMS contains meta-information such as a package description, version, and "dependencies". The package management system can evaluate this meta-information to allow package searches, to perform an automatic upgrade to a newer version, to check that all dependencies of a package are fulfilled and/or to fulfill them automatically.

Although Linux distributions typically contain much more software than proprietary operating systems, it is normal for local administrators to install software not included with the distribution. An example would be a newer version of a software application than that supplied with a distribution, or an alternative to that chosen by the distribution (e.g., KDE rather than GNOME or vice versa). If the additional software is distributed in source-only form, this approach requires local compilation. However, if additional software is locally added, the 'state' of the local system may fall out of synchronization with the state of the package manager's database. If so, the local administrator user will be required to take additional measures to ensure the entire system is kept up to date. The package manager may no longer be able to do so automatically.

Most distributions install packages, including the kernel and other core operating system components, in a predetermined configuration. Few now require or even permit configuration adjustments at first install time. This makes installation less daunting, particularly for new users, but is not always acceptable. For specific requirements, much software must be carefully configured to be useful, to work correctly with other software, or to be secure, and local administrators are often obliged to spend time reviewing and reconfiguring assorted software.

Some distributions go to considerable lengths to specifically adjust and customize most all the software included in the distribution. Not all do so. Some distributions provide configuration tools to assist in this process. Note that such adjustments are typically site-specific and it is not possible for anyone, including a distribution's designer, to pre-configure the software provided to meet individual requirements. As with all operating systems, Linux and its distributions impose a system administration obligation on its users/operators/owners. Linux distributors differ from most operating system vendors in not claiming that "no administration is required." This honesty can worry potential users who have been told otherwise in marketing claims of other operating systems.

By replacing everything provided in a distribution, an administrator may reach a 'distribution-less' state: everything was retrieved, compiled, configured, and installed locally. It is possible to build such a system from scratch, without using a distribution altogether. One needs a way to generate the first binaries until the system is self-hosting. This can be done via compilation on another system capable of building binaries for the intended target (possibly by cross-compilation). See for example Linux From Scratch.

Choosing a Linux distribution

Further information: [[:Comparison of Linux distributions and List of LiveCDs]]

The diversity of Linux distributions are composed of many technical, organizational, and philosophical variations. Technical variations include support for different hardware devices and systems or software package configurations. Organizational differences are often motivated by technical decisions but also by philosophical or even historical reasons. Some distributions specialise in use on desktops, servers or routers. Other criteria include security, including how quickly security upgrades are available; ease of package management; and number of binary packages available.

There are tools available to help making the decision, such as several different versions of the Linux Distribution Chooser [3] [4] [5] [6] and the universal package search tool, whohas [7] There are some easy ways to try out several Linux distributions before deciding on one. Multi Distro is a Live CD that contains nine space-saving distributions.[8] Tools are available to make such CDs and DVDs, among them Nautopia.[9] In fact, it is not necessary to burn a Live CD in the first place. Virtual machines such as qemu and VMWare permit booting of LiveCD image files. In the case of VMWare, this requires a specific virtual machine to be downloaded.[10] [11] In qemu, the functionality is already included.

Details and interest rankings of Linux distributions are available on DistroWatch and a fairly comprehensive list of Live CDs is FrozenTech's. Some websites such as OSDir.com and OSVids.com offer screenshots and videos as a means to getting a first impression of various distributions.

Installation

The most common method of installing Linux is by booting from a CD that contains the installation program and installable software. Such a CD can be burned from a downloaded ISO image, purchased alone for a low price, or can be obtained as part of a box set that may also include manuals and additional commercial software. New users tend to begin by partioning a hard-drive in order to keep an existing operating system. The Linux distribution can then be installed on the new partition without affecting previously saved data.

Early Linux distributions were installed using sets of floppies but this has been abandoned by all major distributions. Nowadays most distributions offer CD and DVD sets with the vital packages on the first disc and less important packages on later ones. They usually also allow installation over a network after booting from either a set of floppies or a CD with only a small amount of data on it.

Still another mode of installation of Linux is to install on a powerful computer to use as a server and to use less powerful machines (perhaps without hard drives, with less memory and slower CPUs) as thin clients over the network. Clients can boot over the network from the server and display results and pass information to the server where all the applications run. The clients can be ordinary PCs with the addition of the network bootloader on a drive or network interface controller, and hard disk space and processor power can be offloaded onto the client machine if desired. The cost savings achieved by using thin clients can be invested in greater computing power or storage on the server.

Anaconda, one of the more popular installers, is used by Red Hat Linux, Fedora Core and other distributions to simplify the installation process.

Installation on an existing platform

Some distributions let the user install Linux on top of their current system, such as WinLinux. Linux is installed to the Windows hard-disk partition, and can be started from inside Windows itself. Similar approaches include coLinux.

Virtual machines (such as Virtual PC or VMware) also enable Linux to be run inside another OS. The VM software simulates an isolated environment onto which the Linux system is installed. After everything is done, the virtual machine can be booted just as if it were an independent computer.

Demonstration

The difficulty in quickly demonstrating Linux on the computer of a potential new user still remained an obstacle until recently, slowing its adoption as a personal computing platform. However, Knoppix has pioneered the ability to run directly from a "live CD" running entirely in RAM, rather than installing it to the hard drive. Other distributions have followed suit, and live versions are available for, for example, SUSE, Ubuntu, Mepis, and others. Some minimal distributions such as tomsrtbt can be run directly from as little as 1 floppy disk without needing to change the hard drive contents.

Linux User Groups, or LUGs, still provide the primary face-to-face forum for demonstration of Linux. Commercial exhibitions provide Linux demonstrations to potential new users, especially corporate buyers.

The fastest approach is probably that of Workspot, which uses VNC to provide a free Linux desktop demo online.

Interdistribution issues

The Free Standards Group is an organization formed by major software and hardware vendors that aims to improve interoperability between different distributions. Among their proposed standards are the Linux Standard Base, which defines a common ABI and packaging system for Linux, and the Filesystem Hierarchy Standard which recommends a standard filenaming chart, notably the basic directory names found on the root of the tree of any Linux filesystem. Those standards, however, see limited use, even among the distributions developed by members of the organization.

Proprietary software

Some specific proprietary software products are not available in any form for Linux. This includes many popular computer games, although in recent years some game manufacturers have begun making their software available for Linux. For example, Epic Games sells a Linux version of its Unreal Tournament 2004. This problem is also addressed by emulation and API-translation projects like Wine and Cedega, which make it possible to run non-Linux-based software on Linux systems, either by emulating a proprietary operating system or by translating proprietary API calls (e.g., calls to Microsoft's Win32 or DirectX APIs) into native Linux API calls.

See also

Notes

  1. ^ Linux distributions may also be referred to as GNU/Linux distributions. The term "distribution" usually suffices and is often informally shortened to "distro."
  2. ^ http://www.slackware.com/announce/1.0.php
  3. ^ http://www.zegeniestudios.net/ldc/
  4. ^ http://www.tuxs.org/chooser/
  5. ^ http://eedok.voidofmind.com/linux/chooser.html
  6. ^ http://desktoplinuxathome.com/distro.html
  7. ^ http://www.philippwesche.org/2004/programs/whohas/intro.html
  8. ^ http://www.linux.com/article.pl?sid=06/05/22/1353239
  9. ^ http://applications.linux.com/article.pl?sid=06/03/16/1724219&tid=47
  10. ^ http://www.vmwarez.com/2006/02/livecd-player-virtual-machine.html
  11. ^ Emulating Ubuntu in Windows XP using the free VMware Player

Template:Link FA

Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Linux_distribution&oldid=71831536"