Marcelo Tosatti, the deputy that Linux leader Linus Torvalds appointed to maintain the 2.4 Linux kernel, said in a posting to the Linux Kernel Mailing List this week that the follow-on 2.6 kernel is mature enough that it should be the foundation of new projects.
Tosatti will accept some significant changes and some support for selected new hardware in version 2.4.24, now under development. But versions 2.4.25 and beyond will be released only to fix security problems or other critical issues, he said.
"2.6 is becoming more stable each day, and we will hopefully see a 2.6.0 release during this month or January," Tosatti said in a posting to the Linux Kernel Mailing List on Monday.
The 2.6 kernel is in final testing, and its maintainer, Andrew Morton, said in November that he expects to release it in December. The new kernel includes several features, such as the ability to work better on large multiprocessor servers, that are expected to make Linux more appealing to corporate customers.
Tosatti's decision didn't sit well with some who are reluctant to move so soon to untested software.
"I am terrified of the following scenario, which is extremely probable to happen soon," responded Jan Rychter in a Wednesday post. "2.4 is being moved into 'pure maintenance' mode and people are being encouraged to move to 2.6. While people slowly start using 2.6, Linus starts 2.7 and all kernel developers move on to the really cool and fashionable things. 2.6 bug reports receive little attention, as it's much cooler to work on new features than fix bugs."
But shifting attention to the new kernel isn't unreasonable, D.H. Brown analyst Tony Iams said. "It makes perfect sense to me that they'd focus on putting new features into 2.6," he said. "As soon as the new release is ready, the old release goes into maintenance mode. Any software release is going to work that way, whether commercial or open source."
The discussion about 2.4 and 2.6 was triggered Monday by a request by Silicon Graphics programmer Nathan Scott, who on Monday asked Tosatti to accept SGI file system software called XFS. Tosatti rejected the software, saying advocates should submit it for inclusion in 2.6, though he later relented somewhat.
File system software controls how information is written on hard drives, and XFS is a "journaling" file system in which logging features make it easier for a computer to recover from a crash. Three other journaling file systems -- ext3, ReiserFS and IBM's JFS -- have been accepted into the 2.4 kernel.
SGI developed XFS for Irix, its version of the Unix operating system, and said in 1999 it would contribute XFS to the Linux community. But SGI's handling of the software has led to a chilly reception by some -- including Al Viro, a deputy who oversees Linux file system work.
SGI's emphasis could change, however, Iams said.
"Historically, it was true that SGI has focused on Irix as the primary platform for XFS, but I wouldn't be surprised to see that change. They have been having a fair amount of success with the Altix," their Linux-based Itanium server, Iams said. "Not only is it great technology, but they've figured out how to sell it."
Several XFS users backed SGI's request. "We won't be touching 2.6 until it's really stable," said a posting from Dan Yocum of the Fermi National Accelerator Laboratory. He added that his organisation has more than 300 terabytes of data stored using XFS running on 2.4 kernel systems. "It would be very, very nice to have it in the 2.4 tree without having to pull it from SGI."
The opinions of users carry weight in the open-source development process, Iams said. "That's the beauty of the open-source development process. It's driven by the users and the technological dialogue," he said.
