The long-awaited release of the 2.4 Linux kernel occurred January 4 without any of the hoopla that typically accompanies a major software release. Even vaporware announcements in the proprietary OS market include more banging of the drum. Linus Torvalds simply sent a short note (see Resources for a link) to the kernel mailing list, which was picked up by LinuxToday, saying he'd released the kernel. No rock band, no professional wrestler on stage, no laser lights. But even without the fireworks and glitter, the release generated a lot of excitement. By Monday morning following the release late Thursday afternoon, the LinuxToday page carrying Linus's note had been viewed almost 100,000 times. That's an order of magnitude greater than most "big" stories for the publication.

Even after its official release, the 2.4 kernel may not be included in major distributions for weeks or perhaps months. Between now and then, however, early adopters will continue to download and compile the latest version from kernel.org.

Henry Hall, head of Linuxcare's research group, described the 2.4 kernel as an evolutionary release, not a revolutionary one. He said some of Linuxcare's corporate customers have been experimenting with the 2.4 kernel for some time, particularly those with a need for the vastly improved scalability in SMP (symmetrical multiprocessor) machines and in networking that kernel 2.4 promises. Linuxcare employees have contributed code to handle gigabit network cards in the new kernel. The 2.4 kernel fixes the networking problems (spotlighted by the now infamous Mindcraft "benchmarks") experienced in the TCP/IP stack when using multiple network cards.

Bruce Perens, Hewlett-Packard's new Linux lightning rod, views the release as a big step for Linux toward the high end of the enterprise market. Applications like HP's Open Mail, which Perens describes as basically sitting atop sendmail, do not get so intimately involved with kernel code that they need to be tweaked to move from a 2.2 kernel to the 2.4. Perens noted that major-league database makers will probably tweak their products to take advantage of real raw access to disk drives that the new kernel offers. That means faster disk access than with previous releases. Debian is the most popular distribution in use internally at HP, and once a 2.4 package is made available, Perens expects widespread adoption by HP developers.

Perens also said that HP will build machines that take advantage of the improved SMP scalability of the new kernel. He said there are no plans at the moment to provide Linux on the HP 9000 Superdome, which HP claims can scale to 256 processors, though those plans will change eventually. Like Linuxcare, HP has employees who have been intimately involved with 2.4 development, particularly in the area of SMP scalability.

Speaking of Linux in the enterprise, Daniel Frye, director of IBM's Linux Technology Center, said that all of IBM's applications available on Linux will be tested on 2.4. As beta versions of distributions built around the new kernel begin to appear, IBM will vigorously test its applications on them. He added, "If there are problems, we will find them and fix them."

So when will the new distributions appear? Preston Brown, lead Red Hat 2.4 kernel developer, said the Red Hat version will debut "when it's ready." After its own testing period, Red Hat plans to make the 2.4 kernel available as an RPM so that Red Hat Network customers can upgrade their existing Red Hat 7.0 systems to the new kernel. Red Hat does not prerelease its distribution releases, so Brown could not tell us when the next version will appear.

Just can't wait? Join the crowds downloading the 2.4 kernel source code from kernel.org. But know that there may be a few bumps in the road if you do. Some people have reported problems with PCMCIA network card drivers. You can circumvent such hitches by downloading the latest source code from the PCMCIA project and building the drivers yourself (see Resources for a link). So far, I've heard of no applications breaking with the new kernel.