The attempt to bring several Linux distributions together under a single core is doomed. ThatÂ’s according to Mark Shuttleworth, founder of the startlingly popular Ubuntu distribution of Linux, who has predicted that the DCC Alliance initiative will ultimately fail.

DCC and Ubuntu both draw on Debian, a community-oriented Linux distribution that by some measures is the second most widely used in the world after Red Hat Linux. Debian's nebulous nature has made it difficult for enterprises to get a grasp on, however, leading to efforts such as Ubuntu and the DCC, which aim to keep things a bit simpler.

There has been friction between the two groups since it emerged that Ubuntu had no intention of joining the DCC Alliance, whose members include Progeny, UserLinux, Xandros, Linspire and others. Ubuntu was created only about two years ago, but is rapidly becoming more popular than Debian, according to some industry observers.

Shuttleworth is himself something of a celebrity, having in the past 10 years founded security firm Thawte Consulting, sold it to VeriSign for $575 million and taken a ride on a Russian spacecraft to visit the International Space Station.

In a mailing list post earlier this week, Shuttleworth clarified his feelings about the DCC, citing technical and engineering objections as well as concerns such as the project's name.

The DCC began as the "Debian Common Core Alliance", but has since removed direct references to Debian at the request of the Debian community. Shuttleworth said the name continued to be an issue. "There was an attempt to pretend that 'DCC stands for DCC Common Core' but that's pretty much nonsense, even DCC members continue to refer to it as 'Debian Common Core', a name that it cannot legally use," he wrote.

While the DCC uses Debian technology, it hasn't stuck closely enough to Debian for Shuttleworth's taste. "The DCC distro doesn't use the Debian kernel, and it modifies key pieces of the infrastructure like the linking system and core system libraries. So it's not really Debian at heart," he wrote.

At a higher level, Shuttleworth said he disagrees with the fact that the DCC is aiming to create a separate distribution of Debian's Sarge version that's compliant with the Linux Standard Base, rather than working for LSB compliance from within Debian.

"I think if LSB were a goal for Sarge then that could have been achieved directly in Sarge, not in this hybrid fashion," Shuttleworth wrote. "If we were to do LSB for Ubuntu, it would be done directly rather than as a compatibility layer."

Finally, he said he believes the premise of the DCC - using a common core across multimple distributions, in order to make certification easier - is flawed.

One reason is that the concept doesn't leave distributors enough flexibility, he said. "It strikes me that this approach has never worked in the past. In fact, every distro always modifies elements of the core, and with good reason," Shuttleworth wrote.

In addition, the idea of certifying only to a core rather than to an individual distribution isn't practical, he said. "An ISV that certifies an OS is not just certifying the pieces on which it's app depends. It's also certifying the environment which it will support, which includes installer, documentation, even packaging."

Shuttleworth said the end result was that the DCC appeared to be a dead end. "In the early days of the DCC I preferred to let the proponents do their thing and then see how it all worked out in the end. Now we are pretty close to the end," he wrote.

Ian Murdock, founder of Debian and also of the DCC Alliance, said Shuttleworth's objections didn't add up to much.

Murdock said the necessary name changes had been made and that most of those involved were ready to move on. "It's a non-issue to all but a handful of people," he told Techworld. He said the DCC Alliance may acquire a trademark licence to the Debian name and add a Debian reference back in.

He said Shuttleworth appeared to have misunderstood the nature of the technology changes made to the DCC, which he said did not include the linking system and core system libraries.

"We've never claimed that DCC is Debian, only that it's a common core that's as close to pure Debian as possible," he said. "All else being equal, we do things the Debian way with as little deviation as possible." The DCC's aim is binary compatibility with pure Debian.

Murdock said he agreed with Shuttleworth that it would be better to have achieved LSB compatibility from within Debian Sarge, but this hadn't been possible for "various arcane reasons". "I don't think not doing LSB compliance at all is a particularly good solution," he said.

He said the use of a common core wasn't a significant restraint on distributors' ability to innovate, since the core is already largely commoditised. "It's a question of tradeoffs, like most things in this business: What's more important, carte blanche at every level of the software stack or a united front at a level of the stack that's been commoditised anyway?" Murdock said.