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Version 2.6.0 of the Linux kernel is ready for business.

Readers of the linux-kernel mailing list learned that testing of the open-source operating system's new core ended late Wednesday, when Linus Torvalds sent an e-mail beginning with the cryptic phrase "The beaver is out of detox."

The Linux kernel handles communication with input and output devices, and schedules and supervises the execution of other tasks: It is the foundation on which the rest of the operating system is built.

The last production version of the kernel, 2.4, was released in January 2001. A test version of the 2.6 kernel was released in July, with new features extending the operating system's reach into new markets. Version 2.6 has been tested on servers with up to 64 processors, and supports up to 64GB of memory on 32-bit systems. At the other end of the scale, it includes support for low-cost, low-power processors with limited memory management capabilities, often used in embedded devices.

Performance Problems

Version 2.6 should run well on servers, although large database applications will experience performance problems, kernel maintainer Andrew Morton wrote in an e-mail to the linux-kernel mailing list.

Fixes have already been found for some of these, and will be introduced in version 2.6.1 of the kernel, he said. Database application performance can be improved somewhat by changing the default behavior of the kernel's input-output scheduler, he wrote.

Desktop and laptop users may still see some bugs, as the variety of available hardware in such machines makes testing more difficult, Morton said.

Bug Fixes

Even though version 2.4 was released almost three years ago, volunteers around the world are still contributing patches and fixes to it, making the decision to declare version 2.6.0 ready, and put an end to testing, seem somewhat arbitrary.

The first of eleven test versions of the 2.6 kernel was released on July 13. Since the sixth one appeared in late September, the number of bug fixes has been shrinking with each new release.

"The patch from -test11 is a svelte 11KB in size," Torvalds wrote to the linux-kernel mailing list Wednesday. "It's not the totally empty patch I was hoping for, but judging by the bugs I worked on personally, things are looking pretty good."

A number of bugs remain, but are "not considered to be release-critical," he said. Fixes for some of them are already being tested, but "they just didn't have the kind of verification yet where I was willing to take them," he said.