Zemlin didn't bring up the fact that key maintainers of the Linux kernel are getting older. That was for Jonathan Corbet, editor in chief of the Linux Weekly News, to point out later during a panel Wednesday at the Linux Foundation Collaboration Summit, in San Francisco.
Greg Kroah-Hartman, maintainer of the sysfs kernel subsystem, noted, "Turnover at the upper level is not happening. We're all still there. But the rate of change still keeps going up If we're in the way, let us know."
James Bottomley, SCSI subsystem maintainer, added: "There are more gray beards. Coding wisdom is going up. The graying of the Linux kernel is going to continue, frankly, until people start dying," he said.
Andrew Morton, a key aide to Linux' lead developer Linus Torvalds and often referred to as the "Colonel of the kernel," put the issue equally bluntly: "Yes, we're getting older, and we're getting more tired. I don't see people jumping with enthusiasm to work on things the way that I used to."
But he added that meant the developers in the kernel process had gained deep knowledge of the code they're working with and are willing to tackle greater complexity in making additions.
"The people are more complex. The code is more complex. We have stuff getting in now that we would have run away from 10 years ago," he said. The kernel maintainers will encourage youthful enthusiasm, when they find it, he added.
Each two month release of the Linux kernel tends to include about 10,000 changes, with 1,100-1,200 developers contributing code, many of them for the first time. The process hasn't slackened, he said.
Linux remains a strong presence in the enterprise data center and Zemlin cited future growth in Linux' growing adoption in mobile devices. Google's Android operating system is an adaptation of Linux for mobile computing and is used on a new generation of smart phones and other devices.
Work continues on the MeeGo mobile device system, a combination of Intel's Moblin and Nokia's Maemo projects, he noted. Linux also powers many netbooks and nettops.
Zemlin said Linux product makers need to learn a lesson from experts in software product "fit and finish," then flashed a tongue-in-cheek depiction of Apple's Steve Jobs (taken off YouTube) where his comments are run together until he says "it's magical, fabulous, great, unbelievable, great, gorgeous, super high quality, super responsive, awesome."
Despite poking fun, Linux developers need to learn from Apple's ability to listen to consumers and provide easy to use devices, he said.
In addition Linux is playing a strong role in cloud computing. Linux is the operating system powering 90% of the virtual machines in the cloud, even when it's a strongly proprietary vendor supplying infrastructure as a service, said Sam Ramji, VP of product strategy at Sonoa Systems, during the panel, "Does Open Source Mean Open Cloud?"
The panel concluded that it does not, but cloud computing is encouraging the adoption of more open source code.
IBM's Dan Frye, VP of open systems development at IBM, reminded attendees in a keynote address that his firm invested $1 billion to get its product line to support Linux 10 years ago.
The firm struggled to contribute to Linux as well, judging it to be in its strategic interest to build up an x86 version of Linux that would offer an alternative to Windows and compete with Sun's Solaris.
Early in the process, IBM attempted to contribute large blocks of code for general Linux improvement but also in support of particular parts of its product line and was frustrated many times as they were rejected.
Attendee Matt Mackall, lead developer on the Mercurial open source project and a former member of the Linux Foundation's Technology Advisory Board, said he remembered IBM submitting a block of code for extended volume management of disk drives.
"A lot of people had to learn what it was," he recalled. "Linus didn't know what volume management was. For a long time it appeared to be going in, then it was rejected as 'just not salvageable'" for kernel development purposes, with Torvalds making the final decision, he recalled. (The Mercurial project produces a cross-platform software revision management tool for developers.)
Frye didn't mention the incident but said IBM contributed big chunks of code, a scheduler and file systems, that did not get in. He said IBM had to learn to work with the process, encourage IBM developers to participate as individuals in it and offer responses to questions as individuals, not "canned responses from the whole corporation," and contribute their own expertise where it served a purpose.
Since those early days, IBM hasn't attempted to make a large contribution to the kernel but has made many incremental small ones, a process that works much better.
Torvalds reviews new code additions as potentially carrying as much long-term liability as new value and rejects what does not fit into the kernel as an easily maintained module that avoids impinging on other systems.
In the long run, said Frye, it's in the interest of all vendors who back Linux to support such decision making because it produces a stronger operating system for future use.
"No one controls the open source process. If you try, you will make things worse," he concluded.
