A number of the pre-packaged versions of the open source operating system, including Caldera Systems' eServer desktop and server products, won't run on Pentium 4-based computers because the software cannot identify the chip, Intel officials acknowledged. Intel, however, said it was up to the individual Linux vendors to update their operating system releases to bring them into compliance. As originally reported on the LinuxGram Web site, the only versions of Linux that Intel has certified as working properly with the Pentium 4 are Red Hat's Red Hat 7.0 and TurboLinux's TurboLinux 6. Other major Linux releases -- including products from Caldera, Corel, MandrakeSoft, and SuSE -- do not currently include CPU-identifying information in their own CPUID databases. As a result, when someone tries to install one of those versions of Linux, the operating system doesn't recognise the chip and the installation is suspended. It is unclear when some of these versions of Linux will be updated to work with the Pentium 4. Corel and SuSE could not be reached by the deadline for this story. Darren Davis, Caldera's vice president of engineering, said Caldera made a conscious decision not to add Pentium 4 support to its currently shipping eServer 2.3 and eDesktop 2.4 products. Instead, Caldera plans to add Pentium 4 support to its second-quarter updates for both of those products, which will be based on the Linux 2.4 kernel. "We'll do what our customers demand," maintained Davis. He said there has not been much Caldera customer demand for Pentium 4 -- at least so far. Intel, for its part, maintained that it was the fault of the Linux vendors that they had not kept pace with Intel's CPU rollout schedule. "We went to everyone in the [Linux distribution] community [to insure they had the CPUID information for the Pentium 4]," said George Alfs, Intel's Pentium 4 spokesman. "We've had this information out there for quite a while. That's why Turbo and Red Hat already are in compliance." Caldera's Davis basically agreed with Alfs' characterisation, noting that Intel gave Caldera all the (Pentium 4) information it needed. He said that Caldera decided to aggregate all of its fixes and patches into the upcoming second-quarter upgrades, rather than issue a Pentium 4 fix separately. Alfs said that in order to support Pentium 4, Linux vendors simply need to use the sample CPUID code supplied by Intel or to download the Test 11 release of the Linux 2.4 kernel, which includes the Pentium 4 CPUID code as part of the base release. The final version of Linux 2.4 is expected to be available later this month. Red Hat's Linux boots on the Pentium 4, but product manager Marty Wesley said problems are likely to crop up afterward. "We don't support it. We believe there are some problems that have yet to be fixed," he said. The Pentium 4 problems will be fixed with the next version of Red Hat's Linux, code-named Florence and expected in the first quarter of 2001, he said. That version should use the upcoming Version 2.4 of the heart of Linux, called the kernel. The CPUID problem is different for different Linux companies because they often use different installation programs, Wesley said. Pentium 4 computers went on sale 20 November after a series of delays. While the Pentium 4 runs at a faster clock speed than other chips on the market, benchmark testers and other analysts have said that the chip so far doesn't provide quantum leaps in performance. It does well on multimedia applications, but worse than the fastest Athlon from Advanced Micro Devices on business applications. News.com's Stephen Shankland and CNET News.com's Michael Kanellos contributed to this story Find out how the open source movement is revolutionising the high-tech world at the Linux Lounge. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read other letters.