When the v2.4.0 Linux Kernel was released in January of 2001, it had a new VM designed by Rik van Reil. Nine months later, with the release of 2.4.10, Linus shockingly ripped it out, replacing it with a VM provided by Andrea Arcangeli. Though an impressive feat, to this day the VM is still a sore point with many Linux users. Fortunately, with recent releases (especially in the -aa branch, where Andrea does his testing) the current VM is rapidly stabilizing.

Rik, however, continues to develop his VM, with a strong following. (Alan Cox, for example, continues to include Rik's VM in his branch, as does Red Hat.) The rmap VM is currently up to version 12, with version 11 and beyond being labled "ready for use" by Rik.

Louis Garcia posted some questions to the lkml, wanting to learn more. What follows are his questions and Rik's answers. Ultimately, it appears, much of Rik's efforts are targeted for 2.5 inclusion.

The OpenBeOS team recently had their first internal release. It is described on their project news page with the quote, "Baby steps along the path to glory..."

This first release is intended to be installed on top of an existing 5.03 installation, containing "the most up-to-date versions of OpenTracker and the Mail Daemon Replacement, and several replacement Preferences apps (Keyboard, Menu, Mouse, Screen, VirtualMemory, and Workspaces)."

The release produced a little friction among some of the OpenBeOS mailing list members, as the announcement was found on external websites before being posted internally on the mailing list. A brief sampling of th exchange follows, focusing mainly on project leader Michael Phipps' explanation.

Their project page describes OpenBeOS:

"OpenBeOS is a project dedicated to the re-creation, followed by the extension, of the BeOS."

"Individual servers and APIs (known as kits) are being re-written from scratch by an enthusiastic team of volunteers who want to continue the revolution started by Be Inc. The kernel is being based on NewOS, a microkernel written by a former Be engineer, and adapted by a dedicated team of hard core programmers."

Yay! The lkml server, vger.kernel.org, is back up and running; we can all get our lkml fix once again ;)

Based on an anonymous submission:

UnderLinux has an interesting interview with Harald Welte, a member of the netfilter/iptables project core team. In the interview, Harald tells about his carrer, difficulties with the iptables project, Brazil and Free software,
GNU/HURD and, of course, the new iptables2.

To read the interview follow this link. (UnderLinux is a Brazillian site, but this link is to an English translation of the interview.)

A recent thread on the Linux kernel mailing list (lkml) started off by generally bashing Eric S Raymond (ESR). Sifting through the many insults and round trip name calling, though, there was some constructive debating.

The thread was initiated by Jeff Garzik, in response to a message on the kbuild developer's list. The message, from ESR, is a four-point list of suggestions, asking members of the kbuild developer's list to speak with Dirk Hohndel about CML2 and kbuild-2.5, who in turn was to speak with Linus. That thread continues constructively, discussing the pro's and con's of both new systems.

In a recent posting to the lkml, Al Viro announced an up-to-date guide for porting filesystems from the 2.4 stable kernel to the 2.5 development kernel. Unpacking the 2.5.5-pre1 source tree or later (found here), it can be found in the directory 'Documentation/filesystems/porting'. He stressed that it was important to keep this information up to date. It also includes notes on changes that break things.

As detailed in his email, there are two changes currently that break existing file systems: umsdos and intermezo. Al says, "The former will be fixed after the next series of file_system_type cleanups. The latter is a victim of current changes in locking scheme. Help from intermezzo folks would be a good idea - preferably in the form that would reduce the dependency on the VFS guts".

What follows is Al's email, and a snapshot of the following pieces of documentatino from 2.5.5-pre1: porting, directory locking, and Locking.

(excerpt from slashdot)
There's a lengthy interview with Alan Cox. He talks about his responsibilities at Red Hat, Microsoft, the Linux Standard Base, etc.

Recently on the help-hurd mailing list, Ludovic Court

Kerneltrap has spoken with Linux kernel hacker, Andrew Morton. His contributions cover a wide range of kernel components, including ext3 on 2.4 and the low-latency patch. Currently he works for moxi.com.

Robert Love's now-famous preempt Linux Kernel patch has finally been integrated into the main tree. Quoth rml, ""I removed all the sched.h dependencies and this reduced the size of the patch greatly. I now use current_thread_info() and none of the header or include hackery from before. I've tested this with and withot preemption enabled with success."

Browse the linux kernel bitkeeper page for details.

Partha Narayanan, from IBM, recently posted some benchmark perfomance results for Ingo's O(1) Scheduler. The tests were run on an 8-way 700Mhz Pentium III, with several comparisons. These included tests with only one CPU enabled, with 4 CPUs enabled, and with all 8 CPUs enabled. The tests were all on the 2.4.17 kernel, comparisons between the the old scheduler and several revisions of the O(1) scheduler, the latest tested being -J2. (As of this posting, the current revision is -J4)

The end result is around an 18% improvement with a single CPU, around a 45% improvement with 4 CPUs, and around a 187% improvement with 8 CPUs. Pretty impressive!

The benchmark used was the Java based ValanoMark. The raw data follows...

Kerneltrap has spoken with Linux guru Alan Cox. He is perhaps the second most influential Linux kernel hacker, next only to Linus. In this interview he talks about himself, his history with computers and Linux, working for Red Hat, Marcello and the 2.4 kernel, the DMCA, the future of Linux and much more.

Fans of Ingo Molnar's scheduler patch will be happy to learn that Linus has accepted it into the 2.5 development kernel with 2.5.2-pre10. In releasing his latest update, Ingo comments, "now that Linus has put the -D2 patch into the 2.5.2-pre10 kernel, the 2.5.2-pre10-E1 patch has become quite small :-)".

The -pre10 changelog follows, as does Ingo's E1 changelog.

Ingo Molnar recently posted a patch to the lkml that, in his own words, is "a pretty radical rewrite of the Linux scheduler". He includes links to the patch for 2.5.2-pre6 and 2.4.17. Find the latest versions here. The stated goals are:

• retain the good things from existing scheduler
• fully O(1) scheduling
  
• 'perfect' SMP scalability
• better SMP affinity

His very informative email follows...