provide free and quality software to any user. Linux has become the premier platform for open source software, much of it developed by the Free Software Foundation’s GNU project. Many of these applications are bundled as part of standard Linux distributions, and most of them are also incorporated into the Ubuntu repository, using packages that are Debian compliant.
Along with Linux’s operating system capabilities come powerful networking features, including support for Internet, intranets, and Windows networking. As a norm, Linux distributions include fast, efficient, and stable Internet servers, such as the Web, FTP, and DNS servers, along with proxy, news, and mail servers. In other words, Linux has everything you need to set up, support, and maintain a fully functional network.
With the both GNOME and K Desktop Environment (KDE), Linux also provides GUIs with the same level of flexibility and power. Linux enables you to choose the interface you want and then customize it, adding panels, applets, virtual desktops, and menus, all with full drag-and-drop capabilities and Internet-aware tools.
Linux does all this at the right price: It is free, including the network servers and GUI desktops. Unlike the official Unix operating system, Linux is distributed freely under a GNU General Public License (GPL) as specified by the Free Software Foundation, making it available to anyone who wants to use it. GNU (which stands for GNU’s Not Unix) is a project initiated and managed by the Free Software Foundation to provide free software to users, programmers, and developers. Linux is copyrighted, not public domain; however, a GNU public license has much the same effect as the software’s being in the public domain.
The GNU GPL is designed to ensure that Linux remains free and, at the same time, standardized. Linux is technically the operating system kernel—the core operations—and only one official Linux kernel exists. People sometimes have the mistaken impression that Linux is somehow less than a professional operating system because it is free. Linux is, in fact, a PC, workstation, and server version of Unix. Many actually consider it far more stable and much more powerful than Microsoft Windows. This power and stability have made Linux an operating system of choice as a network server.
Open Source Software
Linux is developed as a cooperative open source effort over the Internet, so no company or institution controls Linux. Software developed for Linux reflects this background.
Development often takes place when Linux users decide to work together on a project. The software is posted at an Internet site, and any Linux user can then access the site and download the software. Linux software development has always operated in an Internet
environment and is global in scope, enlisting programmers from around the world. The only thing you need to start a Linux-based software project is a Web site.
Most Linux software is developed as open source software, and the source code for an application is freely distributed along with the application. Programmers over the Internet can make their own contributions to a software package’s development, modifying and correcting the source code, which is included in all its distributions and is freely available on the Internet. Many major software development efforts are also open source projects, as are the KDE and GNOME desktops along with most of their applications. The OpenOffice office suite supported by Sun is an open source project based on the StarOffice office suite (Sun’s commercial version of OpenOffice). You can find more information about the Open Source Initiative at www.opensource.org.
Open source software is protected by public licenses that prevent commercial companies from taking control of the software by adding modifications of their own, copyrighting those changes, and selling the software as their own product. The most popular public license is the GNU GPL, under which Linux is distributed, which is provided by the Free Software Foundation. The GNU GPL retains the copyright, freely licensing the software with the requirement that the software and any modifications made to it are always freely available. Other public licenses have been created to support the demands of different kinds of open source projects. The GNU Lesser General Public License (LGPL) lets commercial applications use GNU-licensed software libraries. The Qt Public License (QPL) lets open source developers use the Qt libraries essential to the KDE desktop.
You can find a complete listing at www.opensource.org.
Linux is currently copyrighted under a GNU public license provided by the Free Software Foundation, and it is often referred to as GNU software (see www.gnu.org). GNU software is distributed free, provided it is freely distributed to others. GNU software has proved both reliable and effective. Many of the popular Linux utilities, such as C compilers, shells, and editors, are GNU software applications. Installed with your Linux distribution are the GNU C++ and Lisp compilers, Vi and Emacs editors, BASH and TCSH shells, as well as TeX and Ghostscript document formatters. In addition, many open source software projects are licensed under the GNU GPL. Most of these applications are available on the Ubuntu software repositories. Chapters 6 and 7 describe in detail the process of
downloading software applications from Internet sites and installing them on your system.
Under the terms of the GNU GPL, the original author retains the copyright, although anyone can modify the software and redistribute it, provided the source code is included, made public, and provided free. Also, no restriction exists on selling the software or giving it away free. One distributor could charge for the software, while another could provide it free of charge. Major software companies are also providing Linux versions of their most popular applications. Oracle provides a Linux version of its Oracle database. (At present, no plans seem in the works for Microsoft applications, though you can use the Wine, the Windows compatibility layer, to run many Microsoft applications on Linux, directly.)
Ubuntu Editions
Ubuntu is released in several editions, each designed for a distinct group of users or functions (see Table 1-1). Editions install different collections of software such as the KDE, the XFce desktop, servers, educational software, and multimedia applications. ISO images can be downloaded directly or using a BitTorrent application.
PA RT I
The Ubuntu Desktop Edition provides standard functionality for end users. The standard Ubuntu release provides a LiveCD using the GNOME desktop. Most users would install this edition. This is the CD image that you download from the Get Ubuntu Download page at www.ubuntu.com/getubuntu/download.
Those who want to run Ubuntu as a server to provide an Internet service such as a Web site would use the Ubuntu Server Edition. The Server Edition provides only a simple command line interface; it does not install the desktop. It is primarily designed to run servers. Keep in mind that you could install the desktop first and later download server software from the Ubuntu repositories, running them from a system that also has a desktop.
You do not have to install the Server Edition to install and run servers. The Server Edition can be downloaded from the Get Ubuntu Download page.
Users who want more enhanced operating system features such as RAID arrays or file system encryption would use the alternate edition. The alternate edition, along with the Desktop and Server editions, can be downloaded directly from http://releases.ubuntu.com/
hardy or http://releases.ubuntu.com/8.04.
Other editions use either a different desktop or a specialized collection of software for certain groups of users. Links to the editions are listed on the www.ubuntu.com Web page.
From there you can download their live/install CDs. The Kubuntu edition used KDE instead of GNOME. Xubuntu uses the XFce desktop instead of GNOME. This is a stripped down and highly efficient desktop, ideal for low power use on laptops and smaller computer. The Edubuntu edition provides educational software and can also be used with a specialized Edubuntu server to provide educational software on a school network. The Goubuntu edition is a modified version of the standard edition that includes only open source software, TABLE 1-1 Ubuntu Editions
Xubuntu Uses the Xfce desktop instead of GNOME, www.xubuntu.org. Useful for laptops.
Edubuntu Installs educational software: Desktop, Server, and Server add-on CDs, www.edubuntu.org.
Goubuntu Uses only open source software; no access to restricted software of any kind, www.ubuntu.com.
Ubuntu Studio Ubuntu Desktop with multimedia and graphics production applications, www.ubuntustudio.org.
Mythbuntu Ubuntu Desktop with MythTV multimedia and digital video recorder (DVR) applications, www.mythbuntu.org.
with no access to commercial software of any kind, including restricted vendor graphics drivers such as those from Nvidia or ATI. Only X.org open source display drivers are used.
The Ubuntu Studio edition is a new edition that provides a collection of multimedia and image production software. The Mythbuntu edition is designed to install and run the MythTV software, letting you use Ubuntu to operate as a multimedia DVR and video playback system.
The Kubuntu and Edubuntu editions can be downloaded directly from http://releases .ubuntu.com.
The Gobuntu, Mythbuntu, Xubuntu, and Ubuntu Studio are all available, along with all the other editions and Ubuntu releases, on the cdimage server at www.cdimage.ubuntu.com.
Keep in mind that all these editions are released as LiveCDs or DVD install discs, for which there are two versions: a 32-bit x86 version and a 64-bit x86_64 version. Older computers may support only a 32-bit version, whereas most current computers will support the 64-bit versions. Check your computer hardware specifications to be sure. The 64-bit version should run faster, and most computer software is now available in stable 64-bit packages. Table 1-2 lists Web sites where you can download ISO images for the various editions.
The http://releases.ubuntu.com and www.cdimage.ubuntu.com also hold BitTorrent and Jigdo download files for the editions they provide.
NOT E
NOT E Ubuntu also provides releases for different kinds of installations on hard drives. These include a Server disc for installing only servers, and an alternate disc for supporting specific kinds of file systems and features during an installation, such as RAID and LVM file systems.
TABLE 1-2 Ubuntu CD ISO Image Locations
URL Internet Site
www.ubuntu.com/getubuntu/download Primary download site for desktop and servers.
http://releases.ubuntu.com/8.04 www.cdimage.ubuntu.com/releases
Download sites for alternate, server, and desktop CDs and the Install DVD, as well as BitTorrent files.
http://release.ubuntu.com Download site for Ubuntu editions, including Kubuntu and Edubuntu. Also check their respective Web sites.
www.cdimage.ubuntu.com Download site for all Ubuntu editions, including Xubuntu, Mythbuntu, Goubuntu, and Ubuntu Studio. Also check their respective Web sites.
Includes Kubuntu, Ubuntu, and Edubuntu.
https://launchpad.net Ubuntu mirrors.
http://torrent.ubuntu.com Ubuntu BitTorrent site for BitTorrent downloads of Ubuntu distribution ISO images.