Operating Systems

Selecting a Linux or Linux/390 Distribution

5 Pages

A common question people ask about Linux is, “What’s the best Linux distribution?” The answer is usually something along the lines of “Use what I like to use this week.” With nearly 400 Linux distributions on DistroWatch and more emerging, selecting a distribution can be a daunting task. This article offers insight on selecting a distribution, especially those appropriate for business use.

Only a few Linux distributions have significant market share, and even fewer have mainframe versions. This greatly reduces the scope of your search. Here are the largest commercial distributions:

  • Red Hat has approximately 50 percent of Linux sales worldwide
  • Novell’s SUSE Linux has about 30 percent of the market
  • Mandriva (formed by the merger of Mandrake and Conectiva) has about 20 percent.

In the mainframe Linux market, SUSE is used in roughly 80 percent of sites, and Red Hat at a little less than 20 percent of the sites. Debian is one of the most popular non-commercial distributions, but since there are no sales figures, per se, it’s impossible to determine where it would fit in and how it would affect the other percentages. Slackware Linux is the oldest surviving commercial distribution, but it has a very small market share, since the owner is more interested in making a living by putting out a quality product than in creating a commercial empire. Slack/390, an official port of Slackware to the mainframe, is noncommercial. CentOS (Community ENTerprise Operating System) is a non-commercial distribution that’s created by rebuilding the source packages that are freely available from Red Hat.

Of these distributions, all but CentOS have commercial support available for Intel and the mainframe. Mandriva doesn’t have a version for the mainframe.

Determine Your Needs

Here are some factors to consider:

Do you need to be on the bleeding edge, or is system stability more important?: Debian’s GNU/Linux is well-known for having long periods between releases. This reflects the large number of architectures the Debian community supports, the many packages included, and the rigorous development and testing process the community employs. For those who require more current software, Debian has three categories of software available: stable, testing, and unstable. For absolute rock-solid stability, stick with the Debian stable release. Debian testing is usually more stable than many so-called production software packages. Debian unstable provides the most current package versions. The packages for Debian on Intel and Debian/390 follow the same pattern.

Slackware has always focused on stability, ease of use, and minimal hardware requirements. (Slackware didn’t move from i386 to i486 as the minimum processor requirement until May 2003, when forced to do so by changes in the GNU Compiler Collection Version 3.2.) After a new version is released, development of the next version begins in what’s known as “Slackware current.” It represents the most current package versions you’re likely to find on Slackware, but probably wouldn’t satisfy someone who was serious about being as up to date as possible. That isn’t the goal of Slackware.

The mainframe port of Slack/390 tries to follow the same philosophy as the Intel version, while accommodating the fact that mainframe Linux is evolving even more rapidly than the Intel version. While Slack/390 is recognized as an official port of Slackware, it’s not a product of Slackware. Although Patrick Volkerding of Slackware has been very generous with advice and expertise over the years, I’m the sole maintainer of Slack/390, and have no official relationship with Slackware.

SUSE and Red Hat both have switched their main focus to serving enterprise customers. In their view, that means less frequent, more stable releases, with a longer period of support. They don’t change package versions within an OS release unless they have no choice. For example, SUSE Linux Enterprise Server 9 (SLES9) shipped with a 2.6.5 kernel. Their SLES9 kernel will remain at 2.6.5 until that version is retired. Security and bug fixes are backported to 2.6.5 as needed. That’s good for sites not wanting to chase the most recent version of everything and for Independent Software Vendors (ISVs) that find it difficult to certify software for a moving target.

5 Pages