The GNU/Hurd home page says, "The Hurd is a collection of servers that run on the Mach microkernel to implement file systems, network protocols, file access control, and other features that are implemented by the Unix kernel or similar kernels (such as Linux)". Over time, however, this may change.

In a recent thread, Farid Hajji offered an update no the Hurd/L4 port. The goal here is to replace the aging Mach microkernel with the newer L4 microkernel. The effort is still in the early stages, Farid describing it so far as a "skeleton project". Current efforts use the Hazelnut implementation (v2), though the plan is to use Pistachio (v4) when it's ready, adding 64bit support.

More details can be found in Farid's email. Read on...

James Simmons announced innocently enough on the lkml, "Just to let you know I created a bitkeeper repository for the framebuffer layer." M. R. Brown replied a couple hours later, "Please tell us that primary framebuffer/input/console development will continue in the CVS drop-in tree on SourceForge? "

This paper presents the results of a benchmark test conducted on a 58-node Cluster 1300 system, simultaneously running eight instances of e-Business Trade 2 benchmark tests on Redhat Linux. This solution mounted in only three racks supported 800,000 users, serving an unprecedented 12,547 requests/sec with an average response time of 0.27 sec/request.

OpenBSD is released on a sixth month development cycle. [earlier story] Unlike many open source Operating Systems, there is no officially available ISO (CD image) for download.

Richard Gooch pointed out that the serial driver was broken in 2.4.19-pre7. Alan Cox explains, "Yes. Someone put the HCDP below not above the basic x86 ports. Tweak include/asm-i386/serial.h and that should be well."

So if you're going to use 2.4.19-pre7 and need your serial port, then you need to apply this patch.

Due to increased spam on the netfilter mailinglist, which is devoted to issues regarding the Linux 2.4/2.5 Netfilter framework, the list maintainer and de facto leader of the Netfilter community, Harald Welte, has made the list "subscribers-only", which prevents people not a member of the list from posting messages on it. This action will prevent any spammers from posting to the list.

Harald also noted in his e-mail that to catch bug reports and legitimate e-mail, he would "manually moderate all rejected mailinglist postings."

Below is the full e-mail.

Mike Fedyk asked on the lkml why the -aa VM update hasn't gone into 2.5 yet. Andrew Morton, who recently split the large -aa update into smaller pieces for 2.4 inclusion explained that now was the wrong time for such an effort. Andrew's current focus in 2.5 is the buffer layer, and because of the intamacy between this layer and the VM, adding the -aa patches "would represent some wasted effort."

Also mentioned was the possibilty that 2.5 will use Rik van Riel's rmap VM, and hence tuning the existing VM would again be "wasted effort". In summary, Andrew offered, "So. My vote would be that unless the VM is actually impeding developers who are working on other parts of the kernel (it is not) then just leave it as-is for the while.".

It was also pointed out that the -aa patches are currently being merged into the 2.4 stable kernel.

Guy Bormann posted a question to the help-hurd mailing list after bowsing Wolfgang Jahrling's Hurd Hacking Guide. The guide looks to be quite useful, saying about itself:

"This document is an introduction to GNU Hurd and Mach programming. The purpose of this guide is to help interested people start hacking the Hurd or extending it (by writing translators). It gives lots of references to the Hurd- or GNU Mach source files. It is recommended that you read through some of these sources. Indeed the Hurd sources are very well written and commented and you can learn a lot by reading them."

Guy's question relates to how various Mach libraries allocate memory, and when it's the progammer's responsibility to free such allocated memory. Marcus Brinkmann offers a detailed reply.

John Looney recently posted to the lkml, asking about the possibilty of one computer serving multiple users. That is to say, multiple keyboards, mice, monitors, etc, hooked up to a single server. The advantages of such a setup in a lab type environment are obvious.

The following discussion ranges through several technical issues with such a configuration, including a kernel limitation of one virtual terminal active at a time, and the typical lack of quality in long video cables. However, none of the issues raised are unbeatable. James Simmons, for example, has been working on cleaning up the virtual terminal code, with many related fixes already merged into Dave Jones' tree.

Another hack exists. Miguel Freitas has a page titled, Multiple local XFree users under Linux on which he details using multiple instances of XFree86 and a dual-head video card to support two keboards/mice/monitors.

Hidetoshi Shimokawa recently posted a link to a FreeBSD FireWire driver, pointing out that it allows you remotely run gdb, even when the host you're debugging has crashed:

"As you know, IEEE1394 is a bus and OHCI supports physical access to the host memory. This means that you can access the remote host over firewire without software support at the remote host. In other words, you can investigate remote host's physical memory whether its OS is alive or crashed or hangs up."

Hidetoshi's full email follow's, as well as a security concern raised by Katsushi Kobayashi.

Today Oskar Andreasson has released version 1.1.0 of his iptables-tutorial package, a series of documents explaining netfilter to the layperson. He mentions quite clearly that he would appreciate it if netfilter coders/experts would "if possible, please have a closer look at the tutorial."

The tutorial can be downloaded at
http://www.boingworld.com/workshops/linux/iptables-tutorial

Below is the full e-mail message.

Byron Stanoszek posted a small patch to the lkml, his efforts at adding 32MB of video card RAM to the system RAM pool on his aging 586. A problem with this effort is the significantly slower speed of video RAM. For this reason, it has been suggested that he turn the video RAM into a block device which could then be added as a fast swap device.

An earlier lkml thread (from April 2000) was also referred to in which the same idea was discussed.

A recent thread on the lkml discussed the "OOM killer". The OOM (out of memory) killer has the task of choosing which process(es) to kill when the VM runs out of memory. Rik Van Riel has a full explanation of the OOM killer here.

Andrew Morton, who's been working on dividing the latest -aa VM into smaller pieces for mainline inclusion, submitted a patch about which he says:

"I have incorporated the oom killer into try_to_free_pages(), along with a tunable which defines how hard we work before killing something. It is *extremely* conservative. As it should be. The VM will spin madly for five or ten seconds before giving up and calling the oom killer. And then another five seconds elapses before the oom killer decides to actually kill something. It works."

The thread goes on to compare the mainline VM with the -aa VM. It also looks at ways to further tune the OOM killer.

The latest LWN kernel summary is out. It includes some interesting news about dealing with discontiguous memory.