Jonathan Corbet is an active kernel contributor, co-founder and president of Linux development community news site LWN.net, and the lead author of Linux Device Drivers, Third Edition. His renowned Kernel Report has been presented to audiences worldwide, and this year in Melbourne will mark his fourth appearance at Linux.conf.au. Here, Corbet offers Computerworld readers a sneak peek at the major themes behind this year's Kernel Report.

What is the main theme of your talk at Melbourne's Linux Conference?

The real purpose of my talk is to bring attendees up to date with regard to what is happening in the kernel development community. It is a fast-moving project which is very hard to keep up with -- the linux-kernel mailing list, alone, can run up to 500 highly technical messages per day. I do follow this community, though, and have gotten reasonably good at summarizing what is happening there -- and making hand-waving predictions about what will be happening in the near future.

How has the kernel development process gone over the past year - What were the major happenings?

The process is running quite smoothly, with four major kernel releases (2.6.20 through .23) being made, and 2.6.24 being brought close to release. I anticipate it will come out just before linux.conf.au begins.

Major events over the last year include the incorporation of several virtualization implementations (KVM, Lguest, Xen), the dynamic tick patches, a completely new wireless networking stack, the CFS process scheduler, and much, much more.

Is the patch flow rate continuing at a high rate?

It is, in fact, increasing, with the 2.6.24 kernel having the highest patch rate yet. Almost 10,000 separate changesets were merged in this development cycle, resulting in the addition of about 300,000 lines of code (and the modification of many more). One big change (the merger of the i386 and x86-64 architecture code) accounted for a lot of patches, but it was still a tiny part of the whole.

Has the number of developers contributing increased, and has the breakdown of who they work for changed much since last year's Kernel report?

The number of developers is approximately the same - over the course of one year, about 2,000 individual developers will contribute at least one patch to the kernel. I have an unquantified sense that more of these developers are being more active, though. Once upon a time, the top 20 developers were responsible for a large majority of the code going into any given kernel release; now they barely do 20%. When the kernel summit program committee tried to identify the 70 or so most important developers, we had a very hard time narrowing down the list. The development community is quite broad, and is becoming more so.

Australia is a heavy contributor to the free software community in general, and to the kernel in particular. One obvious example would be the Lguest hypervisor code, contributed by Rusty Russell. Paul Mackerras is one of the key PowerPC architecture maintainers and gatekeepers. There are many other Australian contributors -- far too many to list.