Red Hat waits for new Linux kernel to pop

Red Hat's newest product for businesses, Red Hat Enterprise Linux 3.0 (RHEL 3.0), released last week, is based on version 2.4.21 of the Linux kernel, the core part of the OS. Customers will have to hold out for RHEL 4 to see Linux version 2.6 in the corporate product, said Brian Stevens, Red Hat's vice president of OS development.

"The reality is it's not ready," Stevens said of the 2.6 kernel.

While Red Hat customers will have to wait for some of the benefits expected with the 2.6 kernel--better performance, security and ability to run on powerful multiprocessor systems, for example--Red Hat is bridging the gap by bringing some of the 2.6 features to the current 2.4 kernel. (The 2.5 kernel, like the earlier 2.3 and the 2.7 to come, is for development use only.)

Red Hat waits 12 months to 18 months between new versions of its corporate product, so it's likely that RHEL 4 with Linux 2.6 will arrive in 2005.

"The timing might be a little bit unfortunate from Red Hat's perspective. It's probably a little bit of a long gap," Illuminata analyst Gordon Haff said. "Hitting 2004 would mean being on the very short end of their release cycle--and that's assuming that 2.6 itself doesn't slip much longer. It seems like a stretch."

The kernel is the foundation of the OS, handling the most basic tasks, such as communicating with networks or hard drives, juggling multiple programs or assigning tasks to specific processors on multiprocessor machines. Improving the kernel is crucial to enabling Linux companies such as Red Hat or its chief rival, SuSE Linux, to compete with Microsoft's Windows or versions of Unix such as Sun Microsystems' Solaris.

Linus Torvalds, founder and leader of the Linux kernel programming project, said a year ago he hoped to release version 2.6 in June 2003. More recently, Torvalds shut off the acceptance of new features in the version to focus solely on bug fixes.

Like Red Hat, SuSE is cautious despite eager anticipation of 2.6 features. "In 2.6, a lot of architectural changes have been integrated into the system, so there's more work involved, and more work is always more prone to failure," said SuSE's chief technology officer, Juergen Geck.

It's better to be safe than sorry, and the fact that future features from 2.6 can be "backported" so they're available in 2.4 gives Linux companies flexibility, Haff said.

"It makes sense to take some extra time and make sure when 2.6 is released that it's pretty solid. You know that the Microsofts of the world are ready to leap on any real or perceived weakness of Linux," Haff said.

Options for the eager
SuSE expects to beat Red Hat out of the gate with a corporate product using the 2.6 kernel. Its SuSE Linux Enterprise Server 9.0 is due in the second quarter of 2004, Geck said.

"The work around it has already started in SuSE," Geck said. "We have to prepare a lot of things around the kernel itself. So far we're on track with our road map."

Though there are several other companies selling Linux, most customers using the OS are affected by the actions of Red Hat and SuSE.

"The market on the server side is in the hands of Red Hat and SuSE," said IDC analyst Dan Kusnetzky, with No. 1 Red Hat and No. 2 SuSE increasing their market share while all others lose.

Less conservative customers, though, will be able to use 2.6-based Red Hat and SuSE software earlier. Red Hat's Fedora project, intended to help new Linux software mature more quickly, is scheduled to release its first product on Monday. The project's next priority will be to incorporate the 2.6 kernel. For more eager customers, Red Hat developer Arjan van de Ven provides 2.6 updates for Fedora.

"We're hoping get out there with Fedora over the next six months, then start turning it into an enterprise release," Stevens said.

SuSE's latest desktop software product, SuSE Linux 9.0, includes an option under which advanced users can run a test version of the 2.6 kernel.

"We feel through releasing the product that carries the technology, we did a very good first step," Geck said. "It's not going to (require) major changes to what we have today."

To fork or not to fork?
The standard Linux kernel approved by Torvalds resides at the Linux Kernel Archives, better known simply as kernel.org. The kernels that ship with SuSE and Red Hat Linux, however, are modified with numerous patches to add or disable various features.

This patching strategy enabled Red Hat, for example, to bring the Native Posix Thread Library (NPTL) from the 2.6 kernel to the 2.4.21 kernel in an attempt to speed Java, databases and other applications that assign simultaneous tasks to separate computing processes called threads.

But patches can pose problems. One risk in open-source projects--as opposed to a centrally controlled proprietary one such as Microsoft Windows--is that different people will take the software in different directions. That "forking" process, while it has some advantages, also can cause problems: Programmers and those making dependent software must decide which fork or forks to support.

For example, a company such as Oracle must ensure its database software works with the forks from both Red Hat and SuSE.

But Red Hat, which employs many influential kernel programmers, tries to keep its kernels from veering too far from the kernel.org ones, Stevens said.

"We won't add patches (to 2.4) unless we feel we can get acceptance into 2.6," Stevens said. For example, although Red Hat patched the kernel substantially with RHEL 2.1, about 90 percent of those patches were accepted into the main kernel. That acceptance meant Red Hat didn't have to support those variations on its own.

While Red Hat expects many of its current patches to become part of the standard Linux kernel when 2.6 arrives, that point is still well into the future.

"It's just so far from ready now," Stevens said.