Apart from differences as you go from one release to another, a proprietary operating system like Windows is the same no matter how you get it. Linux distributions (or 'distros') differ considerably, however. Although they're all based on the same -- or very similar -- core Linux software (kernel), they generally have different user interfaces and varying amounts of bundled application software. As a result, what you actually get, and what you can do with it, will vary widely.
The level of documentation, support and other services available will also vary, as will the amount you’ll have to pay to obtain, deploy and support Linux in your organisation. Some of the free distributions are very specialist and are aimed more at the hobbyist and home users, with minimal support and a fast release cycle. More stable distributions designed for business use are better supported and have slower release cycles, but are becoming increasingly expensive.
As with Windows, there are different desktop and server versions of most Linux distributions. Some vendors also offer so-called 'LiveCD' implementations that can be booted from CD-ROM rather than requiring hard disk installation -- a good way of evaluating the software.
For a complete list of the, literally, hundreds of Linux distributions available, check out www.distrowatch.com. The top five Linux business 'brands' are briefly outlined below.
Very much the market leader in the Linux business sector, Red Hat recently divested itself of its personal distribution to concentrate on the Red Hat Enterprise Linux (RHEL) line. Available for both servers and desktops, RHEL is a well documented and supported business platform that's available through a wide variety of channels.
The Red Hat Linux consumer product was spun off as The Fedora Project in 2003. It’s still sponsored by Red Hat and can be downloaded and used for free. However, this version is now developed independently with community participation, has a much shorter release cycle than RHEL and is used primarily to test new technologies before they’re added to the enterprise product.
Red Hat Enterprise Linux can be specified for factory installation on server and desktop systems from leading vendors including IBM, HP and Dell.
Acquired by Novell in 2003, SUSE Linux software is available in several formats. There’s a freely downloadable consumer implementation simply called SUSE Linux available from www.opensuse.org, or a fully supported commercial package, currently SUSE Linux 10. However, for business use Novell recommends SUSE Linux Enterprise Server (SLES), based on an earlier implementation, which is better supported with a much slower release cycle. At the time of writing, for example, SLES 10 is only just being readied for launch several months after the introduction of the consumer version.
Novell also offers a business desktop distribution, Novell Linux Desktop; like SLES, this is based on earlier, stable, SUSE code. The company has also added Linux support to its NetWare platform to create the Novell Open Enterprise Server.
Novell /SUSE Linux software can be specified for factory installation by many of the leading industry standard server and desktop PC vendors. This again includes HP, Dell and IBM (which invested in Novell to help finance the SUSE purchase).
Originally known as Mandrakelinux, the Mandriva distribution was originally based on the Red Hat software, but with a KDE rather than a GNOME desktop interface. The latest server and desktop implementations can be downloaded from the Mandriva Web site or media packs ordered with varying levels of support and other services available by subscription.
The usual bundle of application software is included with the Mandriva product. Companies looking for a fully supported stable release and an extended update cycle can look to the Mandriva Corporate Server and Corporate Desktop packages, which are based on earlier releases.
Most hardware vendors certify their systems for use with Mandriva Linux and in Europe some HP notebooks can be ordered with the desktop distribution preinstalled.
One of the oldest Linux distros, Debian is a totally free implementation that, although not as popular as Red Hat or SUSE, is widely used in the business market. It has a slow release cycle and is therefore more stable than most of the consumer-orientated free distros. Debian has now largely been superseded by a distribution based on it, Ubuntu.
Based on the Debian distribution, Ubuntu is currently the most popular free implementation of Linux. It attracts wide community support and it’s possible to buy into a range of commercial support services, both from developer Canonical and from third-party organisations. Server and desktop implementations are both available, with a good selection of bundled applications. New versions are released every six months and there’s good support from the hardware vendors.
According to a recent IDC report, the percentage of desktop PCs delivered with Linux as opposed to Windows pre-installed is still in single figures. As a server operating system, however, it’s much more popular: around a fifth of all new servers are loaded with Linux, and virtually all the leading hardware vendors offer some degree of support for the open source platform.
In some cases 'support' will simply be certification of the hardware for Linux deployment. In others it will involve pre-installing Red Hat, SUSE and other distributions onto industry standard systems. Additionally, leading vendors such as IBM offer Linux support on a much wider range of hardware platforms and are also involved in the development of open source applications, either directly or in conjunction with third-party software vendors.
A highly committed open source player, IBM is the leading vendor of Linux-based servers, supporting the operating system on a wide range of its platforms. These include its Intel and AMD powered xSeries products, including both rack-mount and blade servers, plus zSeries mainframes. In the small business sector, too, the company is keen to stress support for Linux on its RISC-based POWER platforms -- Linux on POWER.
Red Hat and Novell/SUSE are the preferred distributions, as IBM has close ties to both companies. IBM also offers a range of installation, migration and support services, and is a leading developer of commercial middleware and other applications for the Linux platform.
Like IBM, HP is a committed proponent of Linux and open source software and has partnered with both Red Hat and Novell/SUSE. Linux distributions from both can be preinstalled on the company’s industry-standard ProLiant and Integrity servers, including its blade products. Linux is also supported on HP’s RISC platforms.
HP offers a comprehensive set of installation, support and outsourcing services to help businesses deploy Linux. The company also provides support for the Linux open source platform within its management and other software solutions.
Dell offers to preinstall either Red Hat or SUSE Linux distributions onto its PowerEdge industry-standard servers, including blade server products. The exact implementations available will depend on the server specified. The company has a Linux community Web site, and also offers a range of installation and support services to Linux customers.
In addition to its proprietary Solaris OS and RISC processors, Sun has committed itself to offering support for Linux and industry-standard hardware solutions. To that end, Red Hat and SuSE distros are both available on Sun's industry-standard servers; and with the latest Solaris 10 operating system, it’s possible to run Linux applications natively. Sun is also responsible for development of the Java Desktop System, StarOffice (the office productivity suite for both Solaris and Linux systems) and other open source solutions.
Like other leading industry-standard server vendors, Fujitsu Siemens is publicly committed to supporting Linux and open source. Its Intel and AMD platforms are certified for use with Red Hat and Novell/SUSE Linux distributions, and these implementations can be specified when ordering many of the company’s free-standing, rack-mount and blade servers. Linux support and services are also available.
The specialist skills required to manage and support general-purpose Linux servers aren’t always available in a small business, but that doesn’t have to be an issue. Another way to exploit the benefits of Linux is by using server appliances where both the Linux OS and associated application software are supplied ready-installed. Any additional management will then, typically, be done via a browser, with the appliances falling into one of the following two categories:
Some Linux-based appliances attempt to replicate the functionality of a general-purpose server. These, typically, support shared Internet connectivity -- acting as a secure gateway/firewall between the Internet and the local network -- as well as allowing Windows users to share information via a Samba file server. Many will also provide intranet Web server facilities, an email server and collaboration facilities, plus a database back end.
Sometimes it’s possible to buy just the software and install it on a platform of your own choice; otherwise a complete hardware/software package is provided.
Although the big vendors have all dabbled in general-purpose Linux appliances at some time, few now offer them. Instead, the vendors are all smaller companies such as Axentra with its Net-Box software, Equiinet with the NetPilot product line, Inty with ExoServer and Net Integration with Nitix.
As the number of general-purpose Linux appliances has fallen, developers have started to use the Linux appliance format to provide more specialist functionality. Although many Network Attached Storage (NAS) appliances, for example, are architected this way, the most popular use is as a platform for network security.
As with general-purpose appliances, the Linux OS is nearly always hidden behind a Web management interface, and used to configure and manage a range of security functionality. In some cases this will be very specific: for example, many firewalls, SSL VPN and email anti-virus, anti-spam and content filtering appliances are based on open source software. Others provide an integrated platform for multiple security tools as with so-called Unified Threat Management (UTM) appliances.
A Linux server by itself is of very little use: it’s the application software running on it that provides the functionality a small business requires. Things like file sharing, an intranet or public Web server, email server, database engine and so on. Some of these applications will be bundled with the Linux distribution, others are available separately both from the Linux vendors and third-party developers.
What you get in the way of bundled application software will vary from one Linux distribution to another, but there are some common components. All come with a whole host of program development tools, for example, such as compilers, debuggers and so on. Likewise, they nearly all come with Samba -- especially the server deployments, as this software enables Linux to support Windows-like file and print sharing. Moreover, in the latest versions, Samba can even replace a Windows domain or Active Directory server.
Another common inclusion is Apache -- arguably, the most popular Web server on the Internet. Apache gives you everything required to support a high-performance Internet or intranet Web server, and most Linux distributions will come with a variety of add-ons to, for example, support Active Pages, PHP and other common Web server technologies.
A variety of email server and collaboration tools will also be included, although not always pre-configured ready for use. Similarly with SQL databases such as MySQL, where what you get is just a database back-end along with management and development tools rather than a ready-to-deploy end-user solution.
Here you’ll be spoilt for choice, since Linux is now a mature platform and it’s unusual to find a developer without a Linux port of at least some of its products. This is especially true when it comes to the big-name vendors such as IBM, Novell, Oracle, SAP and others, all of whom are committed to open source, with a wide range of Linux-based solutions to choose from. Smaller commercial developers of Linux products also abound, with Exchange-like email and collaboration servers a popular offering. In addition, there’s a huge amount of community-developed and supported application software available.
There’s no getting away from the fact that Windows is now very much the preferred operating system on the desktop, with extensive industry support and a huge number of applications to go with it. However, there are alternatives and Linux also makes a good end-user platform, with an ever-increasing number of usable applications for desktop use. Many of those applications have the same functionality as, and a similar interface to, their Windows equivalents. But because they’re open source, they’re much cheaper.
The desktop interface
Windows has just one graphical user interface (GUI), but Linux has several. Fortunately they all work with the same underlying X Windows technology and are interchangeable, making it easy to mix and match. Although different in detail, Linux desktops don’t look that different from Windows; they also behave in much the same way, use similar mouse and keyboard techniques, and are very easy to master.
The most popular Linux desktops are GNOME, the favoured GUI on Red Hat and Ubuntu distributions, and KDE, the standard desktop on SUSE Linux and, optionally, available on others. Which interface you go for is largely a matter of personal preference, but it’s also worth noting that both allow for a high degree of customisation, so they can be made to suit a wide range of users.
As with Linux servers, most open source desktop distributions come with a bundle of application software; there are also lots of commercial and community-developed applications available. Installing and managing such programs used to be an issue, but recent Linux releases have addressed the problems and it’s now no harder to accomplish than with Windows.
Among the bundled software will be graphical tools and utilities to configure the operating system, install new programs, change the look and feel of the desktop, manage files and so on -- just as in Windows. Similarly, all of the vendors will include a browser which, these days, tends to be Mozilla Firefox although others, such as KDE Konqueror and Opera may also be bundled.
Integrated email/calendaring tools such as Novell’s Evolution and Kontact from KDE tend also to be included to provide Outlook-type functionality. In addition you’ll probably also get the Gaim instant messaging tool -- which supports a wide range of networks, including MSN and Yahoo! -- plus another popular desktop tool, GnomeMeeting, for video conferencing.
Linux-based desktop productivity tools have tended to lag behind, and until recently there hasn’t been much to rival Microsoft’s core word processor (Word), spreadsheet (Excel) and presentation graphics (PowerPoint) applications. However, that has changed in recent months with the release of version 2.0 of the OpenOffice suite (or the StarOffice equivalent from Sun), which contains programs that now match their Microsoft Office counterparts. In fact, not only do they have a similar look and feel, but they also offer a high degree of file/document compatibility for companies wanting to support Windows and Linux on the same network.
On the commercial front, Adobe has a Linux implementation of its Acrobat PDF reader and Linux clients are available for most of the mainstream email and groupware solutions, including IBM's Lotus Notes/Domino and Novell's GroupWise.
A large number of commercial security and management tools are, similarly, available for the Linux platform. There’s also a huge amount of community-developed and supported desktop software to be had.