LWN.net Weekly Edition for July 31, 2008

OLS: Shuttleworth on free software development

In the third keynote given at this year's Ottawa Linux Symposium (OLS), Mark Shuttleworth spoke about "The Joy of Synchronicity". In his speech, he discussed his idea of synchronizing releases between major distributions but he also advocated time-based, rather than feature-based, releases for free software in general. He believes that a release has value in and of itself; by doing them on a regular schedule, a project will get into a kind of cadence that is useful for both developers, testers, and users.

Before starting, Shuttleworth was subjected to the traditional introduction by the previous year's keynote speaker—James Bottomley, in this case. Bottomley looked at Shuttleworth's postings to newsgroups over the years, noting three year-long valleys in the graph where there were no postings. It turns out these corresponded to events in Shuttleworth's life. The first is when he received a substantial amount for selling Thawte to Verisign: "when someone is being productive on the mailing list, never give them half a billion dollars," Bottomley said. For the second, he has a pretty good excuse as he was not on planet earth; the last corresponds to starting Ubuntu.

In a nod to Bottomley and the other kernel hackers, Shuttleworth mentioned that he had been working on his slides up until close to the start of his speech, while doing some unrelated things in the background—like updating his system. That picked up a new kernel as well and he did a suspend to RAM when he was done; only later in the cab ride to the Congress Centre did he think: "maybe that was a mistake". It turned out to work just fine, which is a testament to both the kernel and to distribution update mechanisms.

The alliterative theme of the speech was that free software development should be guided by "cadence, collaboration, and customers". The cadence is a regular schedule for releases, similar to what GNOME—who pioneered this technique, according to Shuttleworth—and the Linux kernel do. This gets a project into a rhythm that makes it more predictable, which enables all interested people to schedule themselves around it. He compared this to various development methodologies such as "Agile" and "Lean".

Industries are governed by rules, so if you want to change an industry, you "have to find which rules are only in our heads". Cross-project collaboration is one of those rules. "Nowhere is it written that projects can't collaborate." It is harder to do that if each distribution is working with different versions of the various base-level tools: the kernel, X.org, GNOME/KDE, OpenOffice.org, Mozilla, and so on.

Shuttleworth contends that it is releases, rather than features, that bring attention to Linux. In answer to critics who believe that distributions should compete with each other, he says that is just "an opportunity to create friction." Free software companies don't compete on versions, but rather on philosophies and what things they focus on. He likens it to food courts or automobile sales malls where there are many choices in one location which serves to increase the sales of all.

For major transitions, Shuttleworth is a fan of establishing meta-cycles, the idea that every N releases is a major release, which may result in breaking some backwards compatibility or introducing completely new functionality, along the lines of KDE 4 or GNOME 3.0. As an example, he used a six month release cycle where every fourth or sixth was a major release. For a distribution, that might be a long-term support release, rather than a major change.

One of the key requirements that Shuttleworth sees is the need to "keep the trunk pristine", by doing integration on the trunk and feature development on branches. Along with this is the need for more and better tests. While not necessarily believing in test-driven development, he certainly leans that way. In any case, all the tests should pass before committing to the trunk.

Many projects do not yet have an extensive test suite, but this needs to change. He quoted a Chinese proverb that "the best time to plant a tree is 20 years ago, the second best time is today". He mentioned that he is working on a robot that controls the trunk of a development tree. Developers will request it to merge from a branch, so the robot merges the branch and runs all the tests. If the tests pass, it commits, otherwise it gets kicked back to the developer.

He sees distributions as "an effective conduit of upstream to users," to that end he believes that agreeing on versions of vital infrastructure can only help. Bugs that users find will be more likely to be fixed; those versions will also get better testing which will help developers. It is a conversation that free software should be having because it is a "very exciting idea" that won't work for every project but should be attempted and experimented with.

In answer to criticism about Ubuntu not contributing as much as other distributions would in his proposed synchronized release, Shuttleworth was adamant that it was not true. He hates to see the antagonism and vitriol between distributions. "We have much bigger fish to fry and they are probably not here today."

If all of the distributions were to standardize on a particular version of some project for their next release, what happens if that project falls behind? There are risks associated with that, Shuttleworth admits, but if it were happening, more resources would be available to help the project catch up. In the worst case, perhaps falling back to the previous version would have to happen. "Being tightly coupled has risks."

This is clearly an idea that Shuttleworth feels strongly about, not necessarily that it be adopted fully, but that it be discussed and considered. Certainly some of his ideas have a great deal of merit. We will have to wait and see whether the grander vision will ever be implemented.

Comments (24 posted)

Harald Welte on his new role with VIA

Hiring a well-known free software advocate to oversee efforts to work with the community is a good plan for any company, but for a company that has had rocky community relations, it may be essential. VIA Technologies has done just that, by contracting with Harald Welte to help guide its strategy to work more closely—and less contentiously—with the community. VIA announced a new effort aimed at cooperation with the free software world last April, but got off to a slow start that had people wondering about its commitment to fulfilling that promise. Welte will be well placed to ensure that community concerns are heard within VIA.

Highly visible in the community for his work on things like netfilter/iptables and, more recently, the Openmoko phone, Welte has the skills to provide VIA with excellent advice. He has also won several awards for his work on GPL enforcement as founder and driving force behind the gpl-violations.org project. We caught up with Welte at this year's Ottawa Linux Symposium to discuss his new role.

Because of his work on Openmoko, Welte had been traveling frequently to Taiwan, making a number of industry contacts amongst the companies located in Taiwan. About nine months ago, he was "invited to talk to VIA and give them some feedback from the community". The company, he says, knew from the beginning it needed community input, but how to get that was not decided until late May or early June, when they asked Welte provide it on a regular basis.

The push from within VIA came from management, specifically product management, which is somewhat surprising—in the US and Europe, at least, it is typically engineering that pushes for better community relations. "It's a really big opportunity for me being a representative of the community to talk to a company at this high of a level. That's what makes me very optimistic."

[PULL QUOTE: It's a really big opportunity for me being a representative of the community to talk to a company at this high of a level. That's what makes me very optimistic. END QUOTE]

VIA primarily needs to get drivers and other software for their graphics hardware cleaned up and submitted upstream. It is not just the X.org drivers for 2D and 3D graphics that need to be mainlined, there are also DRM and DRI patches that are maintained out-of-tree. He wants to see kernel patches get moved upstream to kernel.org, while X patches get merged into X.org code. A free 2D driver supporting most VIA chips, old and new, will be available soon.

Welte sees his role as "focusing more on the open source strategy inside VIA". That includes improving the skills of VIA's R&D group so that they produce drivers that are mainline quality. Various kinds of problems exist in the drivers, the coding style may not meet the kernel requirements or they may not use the proper APIs. Currently, drivers exist for new products that are supposed to ship with mainline drivers available; Welte will help ensure that happens. "I perceive myself as community person rather than a VIA person."

He points to Intel as a "shining star" example of supporting free and open source software, though "sometimes they might focus a bit too much on drivers than on open documentation," especially for wireless hardware. One of the areas that VIA is working on is open documentation for its hardware, but Welte isn't sure when those will be released—though some 800 pages were released this week. Schedules are largely out of his control, as they are subject to a wide variety of variables within VIA.

His role with VIA is a chance to "really make a silicon manufacturer understand how the open source community works and what the benefits are to working with it". He will be traveling back and forth from his home in Berlin quite a bit; "that's good, I love Taipei". He has also started to learn to speak Chinese.

It seems like a great fit that, in some ways, Dave Jones predicted in his blog posting linked above: "I'm beginning to think the only way VIA will ever really 'get it together' is if they employed someone from the Linux community who actually understands how all this works, because it seems someone in Taiwan isn't getting the memos." Perhaps a little late, but it seems that VIA has gotten and understood the memos now.

Comments (5 posted)

Interview: Kristen Carlson Accardi

Kristen Carlson Accardi is a Linux kernel developer for Intel's Open Source Technology Group. She is the maintainer for the PCIE hot-plug driver, the SHPC hot-plug driver, and the PCI hot-plug subsystem in the Linux kernel. She is currently working on SATA drivers, including implementing power management features.

Kristen is the benevolent dictator for the upcoming Linux Plumbers Conference. We interviewed her about LPC, why so many Linux developers live near Portland, Oregon, and life as a kernel developer.

What is Linux Plumbers Conf? And why the "Plumbers" part?

Running a conference is a lot of work in addition to your full time job as a Linux kernel developer. What made you decide to start Linux Plumbers Conf?

Most conferences are centered around talks in which speakers present their work, but open source developers often skip the talks so they can discuss ongoing projects face-to-face. How is LPC balancing these needs?

For several years, developers have been organizing individual summits and workshops for particular projects, like networking and file systems. LPC microconfs are similar, but they're held all in the same location and time. Why did you want to put the microconfs together into one conference?

Who is organizing and sponsoring LPC?

Were there any sponsorships you didn't accept?

How did you decide on the location of LPC?

Tell us more about LPC as a green conference.

How did you get started in Linux kernel development?

Portland is home to many top Linux developers, including Linus Torvalds. Why do you think Portland is so attractive to open source developers?

In your opinion, what are some of the most important technical trends in Linux kernel development today?

Tell us about some of the places you've traveled for your job.

Thanks, Kristen, for taking the time to answer our questions.

Comments (6 posted)

Page editor: Jonathan Corbet

Security

OLS: SELinux from academia to your desktop

One of the nice things about conferences is the ability to catch up on where a particular project is headed, generally from one of the lead developers. Ottawa Linux Symposium did not disappoint in this area, with several "State of ..." talks. On day two of the four-day conference, James Morris looked at SELinux from its academic roots to its plans for the future.

SELinux got its start from university research in the 80s and 90s that recognized that Discretionary Access Control (DAC) did not protect very well against the kinds of attacks that were becoming prevalent. This spawned the idea of Mandatory Access Control (MAC), in which the system makes all of the policy decisions regarding access, so users cannot change the permissions on files or other objects at their discretion. SELinux is a MAC system.

Originally developed by US National Security Agency (NSA) in the 90s, SELinux was released under the GPL in December 2000. At the Kernel Summit in 2001, SELinux was proposed for inclusion in the 2.5 development-series kernels (remember those?), but was rejected by Linus Torvalds because there was no consensus amongst the various competing security models. This is what led to the creation of the Linux Security Model (LSM) interface.

It was the LSM interface that got Morris involved in SELinux. It took until the 2.6 release in December 2003 before SELinux was available in the mainline, which is about three years after its release. This is "not atypical for a significant change to the kernel," Morris said.

The next phase was to get it enabled and working in distributions. Because he works for Red Hat, Fedora (Core in those days) was an obvious choice. FC2 was the first release with SELinux, but it was disabled by default because the policy was too strict. "Every time we switched it on, we would find bugs in the applications." Security bugs that is.

So, Fedora came up with the idea of a "targeted" policy that only affected network-facing services. This was released as part of FC3—which formed the basis for Red Hat Enterprise Linux (RHEL) 4. It was an attempt to get SELinux "switched on and doing something useful". It worked well enough that it inspired confidence in the technology by proving it was viable. SELinux developers realized that "if we run into problems, we can fix them".

Since 2005, SELinux has emerged from a research orientation to a tool that is usable—with a very active development community. "Even being part of the project, it's hard to follow all that goes on" in the SELinux community. Morris then outlined some of the more significant developments over the last few years.

The development of the reference policy by Tresys was a tremendous addition to SELinux. It was a "step forward in policy thinking" because it provides a framework around which to design policy. By getting rid of the original "spaghetti code" policy, it "made policy much more understandable to policy developers".

Loadable policy modules broke up the monolithic policy that was originally part of SELinux into separate pieces. Each can then be loaded individually based on "policy booleans". The two of these together allow policy to be built and administered in sensible chunks, as well as allowing sites to "customize policy to support local conditions". Because of library and toolchain improvements, you no longer have to dig through files to edit, compile, and load policy either. Many of the reputation problems that SELinux has stem from the early days when it was well nigh impossible to track down policy problems and fix them.

It is this frustrating user experience that SELinux is trying to tackle these days. The targeted policy is being merged with the "strict" policy and hundreds of modules covering different applications have been added. Policy failure—where the policy is written incorrectly causing a user to be unable to do something they should be able to—is "something you don't want the user to know about", but unfortunately that is unworkable. Because the system is under development, bugs will occur; there is nothing more frustrating for a user than to be denied access but to be unable to figure out why.

That is where setroubleshoot can help. Inspired by GNOME's bug buddy, it alerts the user to policy violations and tries help find the cause of the problem—to the point of suggesting possible fixes. It is somewhat dangerous, in that users may blindly follow the fixes without understanding what they are doing, but it helps psychologically. "Instead of a black box stopping your system from doing what you wanted, now you have a transparent box."

System administrators have a much nicer set of tools to manage policies as well as filesystem labels. audit2why can analyze SELinux output to provide reasons, once again with possible fixes, for policy violations. It is "not the optimum way to develop policy," but it can help. In addition, semanage is the "go to tool" for managing SELinux that is becoming quite powerful.

Policy development has several GUI tools that have become available. SLIDE is an Eclipse plugin that assists in policy development. It also includes support for testing and deploying policies. Hitachi has developed SEEdit, which is a tool that provides a simplified policy language specifically targeted at embedded devices. It is a higher-level language that removes much of the complexity from SELinux policy while still compiling into compatible policy files.

Performance and scalability have been two areas that have seen much work over the past few years. Many performance and memory reduction patches have come from Japan from the work on embedded SELinux. On the performance critical path, RCU has been used to eliminate some locking, while caching values rather than recalculating them has also provided better performance.

One of the areas that the SELinux hackers are most excited about is threat mitigation. "We have seen evidence that SELinux has provided protection for normal desktop users." Tresys tracks these kinds of threats in their SELinux Mitigation News. In the final analysis, this is what SELinux is meant to do, so it is gratifying to see concrete results.

SELinux has been adopted widely in Fedora and RHEL, but plans for the future include making it available on other distributions. Ubuntu is shipping SELinux in addition to AppArmor, while Debian and Gentoo are targeted for better SELinux support. SELinux techniques are being pushed beyond the kernel, into virtualization (XSM), the desktop (XACE), storage (Labeled NFS), and applications like databases (SEPostgreSQL). There is also a push into other operating systems, like the OpenSolaris Flexible MAC project.

The challenges facing SELinux in the future are in areas like usability, which is a "fundamental problem in security", and documentation, which is "not very good, in some ways really bad". Morris also wants to keep the community of users and developers growing.

While SELinux has had a difficult path—first in getting into the kernel at all, then to becoming usable, and finally to actually preventing the kinds of attacks it was designed to stop—the developers seem to overcome each hurdle. It is a complex beast, that in some ways defies analysis, but it can help to protect systems. Like it or hate it, it seems likely to be with us for a long time.

Comments (6 posted)

Brief items

Schneier on free software and liability

Bruce Schneier has often argued that software problems (security-related and otherwise) will not go away until software vendors are made to take on liability for failures. Now he writes that such a regime would not affect free software. "The key to understanding this is that this sort of contractual liability is part of a contract, and with free software -- or free anything -- there's no contract. Free software wouldn't fall under a liability regime because the writer and the user have no business relationship; they are not seller and buyer. I would hope the courts would realize this without any prompting, but we could always pass a Good Samaritan-like law that would protect people who distribute free software."

Comments (17 posted)

Schneier on the DNS vulnerability

Bruce Schneier seems to have lots to say today about things of interest to the free software community. Here is an essay he wrote about the DNS vulnerability—for which the details have leaked—that originally appeared in Wired. We also covered the secrecy issue surrounding the flaw in early July. "Of course, the details leaked. How isn't important; it could have leaked a zillion different ways. Too many people knew about it for it to remain secret. Others who knew the general idea were too smart not to speculate on the details. I'm kind of amazed the details remained secret for this long; undoubtedly it had leaked into the underground community before the public leak two days ago."

Comments (4 posted)

New vulnerabilities

asterisk: multiple vulnerabilities

Package(s):	asterisk	CVE #(s):	CVE-2008-3263 CVE-2008-3264
Created:	July 24, 2008	Updated:	May 4, 2009
Description:	The Asterisk telephony system has two vulnerabilities involving IAX 'POKE' resource exhaustion and Traffic amplification in the IAX2 firmware provisioning system.
Alerts:	Gentoo 200905-01 2009-05-02 Fedora FEDORA-2008-6853 2008-07-30 Fedora FEDORA-2008-6676 2008-07-24

Comments (none posted)

coreutils: restriction bypass

Package(s):	coreutils	CVE #(s):	CVE-2008-1946
Created:	July 30, 2008	Updated:	July 30, 2008
Description:	The coreutils package fails to use PAM properly, allowing a local user (who knows the relevant password) to change to a locked or expired account with the su command.
Alerts:	Red Hat RHSA-2008:0780-01 2008-07-24

Comments (none posted)

ffmpeg: stack-based buffer overflow

Package(s):	ffmpeg	CVE #(s):	CVE-2008-3162
Created:	July 29, 2008	Updated:	April 29, 2009
Description:	From the CVE entry: Stack-based buffer overflow in the str_read_packet function in libavformat/psxstr.c in FFmpeg before r13993 allows remote attackers to cause a denial of service (application crash) or execute arbitrary code via a crafted STR file that interleaves audio and video sectors.
Alerts:	Debian DSA-1781-1 2009-04-29 Gentoo 200903-33 2009-03-19 Gentoo 200901-07:02 2009-01-12 Mandriva MDVSA-2008:157 2008-07-29 Ubuntu USN-630-1 2008-07-28

Comments (none posted)

links: unspecified vulnerability

Package(s):	links	CVE #(s):	CVE-2008-3329
Created:	July 29, 2008	Updated:	July 30, 2008
Description:	From the CVE entry: Unspecified vulnerability in Links before 2.1, when "only proxies" is enabled, has unknown impact and attack vectors related to providing "URLs to external programs."
Alerts:	Slackware SSA:2008-210-04 2008-07-29

Comments (none posted)

vim: multiple vulnerabilities

Package(s):	vim	CVE #(s):
Created:	July 29, 2008	Updated:	July 30, 2008
Description:	A collection of vulnerabilities has been fully patched in vim 7.1. See this advisory for more information.
Alerts:	Slackware SSA:2008-210-10 2008-07-29

Comments (none posted)

Page editor: Jake Edge

Kernel development

Brief items

Kernel release status

The current 2.6 development kernel is 2.6.27-rc1, released by Linus on July 28. Some 8100 changesets were merged during the 2.6.27 merge window; see the article below for a summary. Highlights for 2.6.27 will include lots of new drivers (including the gspca webcam drivers), support for hardware data integrity checking in the block layer, support for checkpointing and restoring of virtual machines in Xen, the ftrace tracing framework, mmiotrace, the tracehook patches, delayed allocation in ext4, the UBIFS filesystem, multiqueue networking, kexec jump, the extension of a number of system calls for safer user-space programming, the lockless page cache (see below), and much more. See the short-form changelog for details, or the long-form changelog for lots of details.

As of this writing, no patches have been merged into the mainline repository since the 2.6.27-rc1 release.

The current stable 2.6 kernel remains 2.6.26; there have not yet been any updates to this kernel, though the word is that the pile of patches for such an update is growing.

2.6.25.13 was released on July 28 with a number of networking-related fixes, some of which appear to address severe problems. 2.6.25.12, with a long list of fixes, was released on July 24.

Comments (none posted)

Kernel development news

Quotes of the week

-- Linus Torvalds

-- Ingo Molnar

-- Matthew Dillon. The whole thread is an interesting read in filesystem design.

-- Linus Torvalds

-- Andrew Morton

Comments (4 posted)

2.6.27 - the rest of the story

The 2.6.27 merge window closed with the 2.6.27-rc1 release on July 28. Some 8100 changesets were merged this time around, making 2.6.27 another busy development cycle. A number of interesting things went in since last week's update; the most significant changes visible to Linux users include:

• There are new drivers for ILI9320 LCD controller chips, Cobalt server LCD frame buffers, SH7760/SH7763 integrated LCD controllers, NXP pca9532 LED controllers, Philips PCA955x I2C LED controllers, WMI-based hotkeys on HP laptops, Maxim MAX73xx I2C port expanders, Micronas DRX3975D/DRX3977D DVB-T demodulators, DvbWorld 2102 DVB-S USB2.0 receivers, MaxLinear MxL5007T silicon tuners, Renesas SH7763 evaluation boards, Renesas Solutions AP-325RXA boards, Renesas R0P7785LC0011RL boards, and Atmel integrated touchscreens. Also added is "mISDN," a new, modular ISDN driver intended to replace older code for a number of ISDN cards. Support for using mISDN drivers remotely via an IP tunnel has been added.

• The Palm T|X handheld computer is now supported.

• The tmpfs filesystem has gained support for asynchronous I/O.

• The hugetlbfs mechanism can now support multiple huge page sizes. There is a new directory (/sys/kernel/hugepages) with information on huge page allocations. The x86 (64-bit) architecture now supports 1GB pages; PowerPC can go to 16GB.

• Most system calls which create file descriptors can now accept a set of flags; this change allows the race-free establishment of close-on-exec semantics, requesting non-blocking opens, and more. Developers wanting to use this capability will have to wait for a version of glibc which adds the requisite interfaces.

• The unmaintained v850 architecture has been removed.

• The kexec jump patch set, which uses the kexec mechanism as an alternative way of implementing suspend-to-disk, has been merged.

• The omfs filesystem has been merged.

• /proc now has a file (called syscall) for each process; when read, it displays the process's current system call and the supplied arguments.

• Linux users hoping to upgrade their systems in the near future will be glad to know that a series of patches designed to make the kernel scale to 4096 processors has been merged.

Changes visible to kernel developers include:

• The tracehook mechanism for defining static trace points (described in this article) has been merged, along with a number of trace points in the core kernel.

• A new, lockless form of get_user_pages() has been added:

      int get_user_pages_fast(unsigned long start, int nr_pages, int write,
  			struct page **pages);
  

  Details of this interface can be found in this article, with the one note that early versions were called fast_gup() instead. (See also the related lockless page cache work, which was also merged).

• The long-debated mmu-notifiers patch has been merged. The notifiers allow external memory management units (as may be seen in some graphics cards or in virtualized guests) to be told about decisions made by the core memory management code.

• There is a new framework for debugging boot-time memory initialization; there's also "a few basic defensive measures" intended to prevent difficult-to-debug boot problems.

• The new function:

      int object_is_on_stack(void *obj);
  

  returns a true value if the pointed-to object is on the current kernel stack.

• There is a new macro for issuing warnings:

      WARN(condition, format, ...);
  

  It's much like WARN_ON() in that it will produce a full oops listing; the difference is the added printk()-style format string and arguments.

• A new helper function:

      int flush_work(struct work_struct *work);
  

  waits for the specific workqueue job work to finish executing.

• dma_mapping_error() and pci_dma_mapping_error() have new prototypes:

      int dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
      int pci_dma_mapping_error(struct pci_dev *hwdev, dma_addr_t dma_addr);
  

  In each case, they have gained a new argument specifying which device the mapping is being done for.

• There are a couple of new radix tree functions:

      unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root, 
                                               void ***results,
  					     unsigned long first_index, 
  					     unsigned int max_items);
      unsigned int radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, 
                                                   void ***results,
  						 unsigned long first_index,
  						 unsigned int max_items,
  						 unsigned int tag);
  

  They are useful for looking up multiple items in a single call.

• Slab cache constructors no longer have a pointer to the cache itself as an argument; they now take a single void * pointer to the object itself.

• The long list of Video4Linux2 ioctl() callbacks has been moved into its own structure (struct v4l2_ioctl_ops) which is pointed to by the ioctl_ops member of struct video_device.

Now begins the long task of finding and fixing all the bugs in all this new code. If the usual pattern holds, that process will take about two months, suggesting that we can expect 2.6.27 sometime in October.

Comments (7 posted)

The lockless page cache

One of the biggest problems in kernel development is dealing with concurrency. In a system where more than one thing can be happening at once, one must always take care to keep multiple threads of control from interfering with each other and corrupting the system as a whole. In the same way that two roads become more dangerous when they intersect, connecting two or more processors to the same memory greatly increases their potential for the creation of mayhem.

Travelers to the US are often amused (or irritated) by the often-favored solution to roadway concurrency: putting in traffic lights. Such a light will indeed (if observed) eliminate the potential for a number of unpleasant race conditions within intersections, but at a performance cost: traffic going through the intersection must often stop and wait. This solution also scales poorly; as more roads (or lanes with different destinations) feed into the same intersection, each of them experiences more red-light time.

In kernel programming, the first tool for controlling concurrency - locks in various forms - are directly analogous to traffic lights. It is not coincidental that the name for a common locking primitive (semaphore) matches the name for a traffic light (semaforo) in a number of Latin-derived languages. Locks enforce exclusive access to a kernel resource in the same way that a traffic light enforces exclusive access to an intersection, and with many of the same costs. When too many processors end up waiting at the same lock, the performance of the system as a whole can suffer significantly.

There are two common approaches to mitigating scalability problems with locks. For many years after the 2.0 kernel came out, these problems were addressed through the creation of more locks, each controlling a smaller resource. Lock proliferation is effective, in that it reduces the chance that two processors will be trying to acquire the same lock at the same time. Since it works so well, this approach has led to the creation of thousands of locks in the Linux kernel.

Proliferation has its limits, though. Adding locks increases complexity; in particular, with more locks, the chances of creating occasional deadlock situations increase. Deadlocks can be avoided through the careful observation of rules on the acquisition of locks, and the order in which they are acquired in particular. But nobody will ever be able to sort out - and document - the proper relative locking order for thousands of locks. So kernel developers must make do with rules for some of the most important locks and the vigilance of the lockdep tool to find any remaining problems.

The other problem with lock proliferation is harder to get around, though. The acquisition of a lock requires writing a value to a location in shared memory. As each processor acquires a lock, it must change that value, which causes that processor to acquire exclusive access to the cache line holding the lock variable. The cache lines for heavily-used locks will fly around the system in a way that badly hurts performance, even if no processor ever has to wait for another to release the lock. Adding more locks will not fix this problem; instead, it will just create more bouncing cache lines and make things worse.

So, as the number of processors grows, the path to continued scalability must not include the wholesale creation of new locks; indeed, it requires the removal of locks in the most performance-critical paths. And that is what this whole long-winded introduction leads up to: the 2.6.27 kernel will include some changes by Nick Piggin which implement lockless operation in some important parts of the virtual memory subsystem. And those, in turn, will lead to faster operation on multiprocessor systems.

The first of these changes is a new function for obtaining direct access to user-space pages from the kernel:

	int get_user_pages_fast(unsigned long start, int nr_pages, int write,
			        struct page **pages);

This function works much like get_user_pages(), but, in exchange for some limits on its operation, it is able to do its job without acquiring the mmap semaphore; that, in turn, can lead to a 10% performance boost on "a threaded database workload." The details of how this function works were covered here last March (though the function was called fast_gup() back then), so we'll not repeat that discussion here.

The other big change is a set of patches which Nick has been carrying for quite some time: the lockless page cache. The page cache holds in-memory copies of pages from files on disk; its purpose is to improve performance by minimizing disk I/O. Looking up pages in the page cache is a common activity; it happens as a result of file I/O, page faults, and more. So it needs to be fast. In 2.6.26 kernels, each mapping (each connection between the page cache and a specific file in a filesystem somewhere) has its own lock. So processors will not normally contend for the locks unless they are operating on the same file. But locks for commonly-accessed files (shared libraries, for example) are likely to be frequently bounced between processors.

Most page cache operations are lookups - read-only operations which make no changes. In the lookup operation, the lock protects a few aspects of the task, including:

1. A given page within the mapping must be looked up in the mapping's radix tree to find its location in memory (if any).

2. If the page is resident in the page cache, it must have its reference count increased so that it will not be evicted before the code performing the lookup has done whatever it needs to do.

The radix tree, itself, is a complicated data structure; it must be protected from modification while the lookup is being performed. For certain, performance-critical parts of the radix-tree code, that protection is done through (1) some rules on what can be called when, and (2) the use of read-copy-update (RCU). As a result, the radix tree lookup can be done in a lockless manner.

There is still a problem, though: a given page may be evicted from the page cache (or simply moved) between steps (1) and (2) above. Should that happen, the second step will increment the reference count for a page which now belongs to a different mapping, and return an incorrect pointer. The kernel developers have, through lots of experience over many years, learned that system crashes resulting from data corruption are quite hard on throughput. So true scalability requires that this kind of scenario be avoided; thus the mapping semaphore, which prevents page cache changes from being made until the reference count has been properly updated.

Nick made an interesting observation here: it actually doesn't matter if the wrong reference count gets incremented as long as one ensures that the specific page mapping is still valid afterward. The result is a new, low-level page cache function:

    int page_cache_get_speculative(struct page *page);

If the given page has a reference count of zero, then the page has been removed from the page cache; in that case this function return zero and the reference count will not be changed. If the reference count is non-zero, though, it will be increased and a non-zero value will be returned.

Incrementing a page's reference count will prevent that page from being evicted or moved until the count goes back to zero. So kernel code which has incremented a specific page's reference count will thereby ensure that the page stays in its current state. In the page cache case, the code can obtain a speculative reference to a page found in a mapping's radix tree. But it does not, yet, know whether it actually got a reference to the page it was looking for - something may have happened between the radix tree lookup and the obtaining of the reference. So it must check - after the reference has been acquired - to be sure that it has the right page. If not, it releases the reference and tries again. Eventually it will either pin down the right page or verify that the relevant part of the file is not resident in memory.

Lockless operation forces a bit more care on the part of the page reclaim code, which is trying to get a page's reference count down to zero so that it can remove the page. Since there is no locking around the reference count now, the reclaim code must set it to zero while checking, in an atomic manner, that nobody else has incremented it. That is the purpose of the atomic_cmpxchg() function, which will only perform the operation if it does not collide with another processor. Since page_cache_get_speculative() will not increment the reference count if it is zero, the reclaim code knows that, by getting that count to zero, it now has exclusive control of the page.

The end result of all this is that a set of locking operations has been removed from the core of the page cache, improving the scalability of that code. There is, of course, a cost, in the form of trickier code with a more complex set of rules which must be followed. Chances are that we will see more of this kind of code, though, as the number of processors in our systems increases.

Comments (10 posted)

OLS: The state of Linux wireless networking

Kernel wireless maintainer John Linville outlined the past, present, and future of the Linux wireless stack on the first day of this year's Ottawa Linux Symposium. In his presentation, he ranged from early efforts, which were "a sore spot for Linux" to the future where it is likely that Linux will have support for some features before "that other OS". Along the way, he looked at various issues that wireless support in Linux faces, including vendor participation, suspend and resume, and regulatory issues.

Linville has been the maintainer Linux wireless for two and a half years since being recruited into the job by David Miller and Jeff Garzik. When he took over, wireless support was in disarray, as there were competing stacks to support different hardware. Users were faced with lots of pain in getting things working when "they just want their hardware to work" said Linville. Since that time, things have greatly changed.

The original wireless hardware was what is called "Full MAC hardware", where the implementation of the wireless protocols was handled by the hardware, generally in firmware. The drivers made these devices appear to be regular wired ethernet devices, though they did require some special configuration for SSID and the like. Because the hardware would enforce various regulatory requirements, vendors would generally work with the community in order to support the hardware.

All of that changed with the advent of "Soft MAC hardware"—which Linville likened to winmodems—where the CPU implements most of the protocol. It is a cheaper solution for vendors, but it requires an 802.11 stack for the kernel. The ieee80211 drivers came along to support the Intel Centrino wireless hardware, but they only supported those few devices. Johannes Berg added the ieee80211softmac driver that added some additional hardware support, but it was a kludgy solution. Since then, Linville said, folks have realized that it was "sort of a mistake to go down that road".

Enter the Devicescape stack. It was a feature rich 802.11 stack for Linux that was popular with developers. After some locking and SMP problems were resolved, it was merged into 2.6.22 as the mac80211 driver. Once that happened, wireless drivers started using it, to the point where Linville showed a chart of the current drivers, almost all of which use mac80211. "It's been a boon to us to pick up the mac80211 code."

One notable driver that does not support mac80211 is the libertas driver for the OLPC. Unlike most other current devices, it is a Full MAC device with special requirements. It has support for power saving modes that do not yet exist in mac80211. Because it is a mesh-networking device that still participates in forwarding network traffic when the system is powered down, it has needs that are not yet supported.

Drivers in progress was the next topic Linville addressed. Several of these are in need of developers to work on them, specifically for the Airgo chipset and Atmel USB chipset. The TI chipset drivers have had some questions raised about the reverse engineering process and may require a legal vetting similar to what the SFLC did for ath5k. Marvell is sponsoring development of a mac80211 based driver for its hardware. This driver may also support 802.11n which allows for greater range and higher speeds than current-generation 802.11.

Using data from LWN, Linville looked at the activity level of the wireless development in Linux. He was amazed to note "how much of the 2.6.26 kernel came through this laptop". Using his Signed-off-by as a proxy for wireless LAN commits, he noted 4.3-5.6% of the kernel commits in the last three releases (.24 through .26) were for wireless. In each kernel, wireless was either the fourth or fifth highest number of commits.

The compat-wireless-2.6 project is aimed at supporting newer hardware in older kernels. Because folks are wary of running kernel.org kernels or their distribution supports an older kernel—but they want to run with the latest hardware—the project backports wireless drivers to kernels as old as 2.6.21. It is a set of scripts and patches that build against the user's kernel. Unfortunately, the project may not last much longer as the multiqueue changes that have been merged for 2.6.27 may change the drivers enough that they will be infeasible to backport.

At the top of the list for new features is removal of the wireless extensions in favor of the new cfg80211 mechanism. According to Linville, "nobody likes wireless extensions, and nobody likes the existing tools". The wireless extensions have vague semantics, can have problems with race conditions, and because they are implemented by ioctl() calls, they encourage duplication of code in multiple drivers. cfg80211 will bring a much cleaner API along with fixing some existing bugs like the 31 character limit for SSIDs.

Access point (AP) mode is another feature that is coming. Typically, APs use similar or identical hardware to that in wireless MACs. For Soft MAC hardware, all that is needed is support on the CPU side for AP mode, which is coming for mac80211. Mesh networking, which has been popularized by the OLPC project, is also coming to mac80211. Cozybit has provided an implementation which will allow Linux to have a feature unavailable for Windows.

Areas that are needed, but are not yet being worked on was next on Linville's agenda. Suspend and resume support is "flawed for mac80211 due to connection management issues". Because mac80211 is unaware of suspend and resume, drivers must work around it by de-registering and re-registering with it, which can be slow. Adding support for suspend and resume is on the list, as is supporting power saving modes.

Linville went on to discuss three big issues that are largely outside of the control of the wireless hackers: firmware licensing, vendor participation, and regulatory concerns. Because drivers for Windows come with the firmware in the driver, many hardware vendors do not license the firmware blob separately. This means that it is unclear what can be done with those blobs. Certain vendors—Intel and Ralink were specifically called out—provide liberal licenses for their firmware. Users are encouraged to "vote with your dollars" by purchasing devices that either do not require firmware or that have a clear, free software friendly license.

Another consideration when deciding which vendors to support is whether they are engaged with the community. For the most part, all vendors but Broadcom are working with the wireless hackers by providing documentation and/or source code. Some are even providing dedicated developers to work on Linux drivers—Intel was the first, but both Atheros (which just released a driver for its ath9k hardware) and Marvell have also begun doing that.

Government regulations about what can and cannot be done in the unlicensed frequencies used by wireless are a concern that is frequently cited by vendors when refusing to work with the community. Unfortunately, their concerns are not completely without merit as hardware vendors are expected to ensure compliance with the regulations. "Non-compliance could be a huge loss" for those companies. As Linville points out, though, most vendors find a way to support Linux drivers.

In answer to a question, Linville said that most WiMAX and 3G wireless devices are Full MAC designs, so there should be little or no regulatory concern, which, in turn, means that Linux support should not be much of a problem—at least until Soft MAC devices come along. Overall, Linux wireless has come a long way, but there is lots still to do. One gets the sense that the wireless team is up to the task.

Comments (26 posted)

Patches and updates

Kernel trees

• Linus Torvalds: Linux v2.6.27-rc1. (July 29, 2008)

• Thomas Gleixner: 2.6.26-rt1. (July 29, 2008)

• Greg KH: Linux 2.6.25.13. (July 28, 2008)

• Greg KH: Linux 2.6.25.12. (July 24, 2008)

• Thomas Gleixner: 2.6.24.7-rt15. (July 28, 2008)

Build system

• Sam Ravnborg: kbuild. (July 28, 2008)

Core kernel code

• Rusty Russell: typesafe callbacks. (July 28, 2008)

• Rusty Russell: Introduce down_try() so we can move away from down_trylock(). (July 29, 2008)

Development tools

• Mathieu Desnoyers: LTTng merge plan. (July 28, 2008)

Device drivers

• Alan Cox: : Proposed fix to the I2O problems with > 4GB space. (July 28, 2008)

• Elias Oltmanns: Disk shock protection in GNU/Linux. (July 28, 2008)

• James Bottomley: final SCSI pieces for 2.6.27. (July 28, 2008)

• Bartlomiej Zolnierkiewicz: IDE updates (part 4). (July 28, 2008)

• Magnus Damm: uio: uio_pdrv_genirq V3. (July 29, 2008)

• Claudio Nieder: [PATCH] Backlight driver for Tabletkiosk Sahara TouchIT-213 Tablet PC. (July 29, 2008)

• Marc Pignat: hwmon: ADC124S501 generic driver. (July 30, 2008)

Documentation

• Thomas Renninger: ACPI BIOS Guideline for Linux. (July 28, 2008)

• Jonathan Corbet: A development process document. (July 29, 2008)

• Randy Dunlap: docsrc: build Documentation/ sources. (July 29, 2008)

Filesystems and block I/O

• Theodore Tso: New ext4 patchset: 2.6.26-git6-ext4-2 // and 2.6.26-ext4-4. (July 28, 2008)

• Al Viro: VFS patches, the first series. (July 28, 2008)

• Evgeniy Polyakov: POHMELFS high performance network filesystem. IPv6 support, documentation update.. (July 28, 2008)

• Erez Zadok: 00/19 fsstack+Unionfs updates/fixes/cleanups. (July 30, 2008)

Janitorial

• Mark Asselstine: Removal of the deprecated cli() sti() functions.. (July 29, 2008)

Memory management

• Peter Zijlstra: Swap over NFS -v18. (July 28, 2008)

• Eric Munson: [PATCH 0/5 V2] Huge page backed user-space stacks. (July 29, 2008)

Networking

• Octavian Purdila: net: per skb control messages. (July 28, 2008)

• Octavian Purdila: net: support for hardware timestamping. (July 29, 2008)

• Octavian Purdila: net: support for TX timestamps. (July 29, 2008)

• Luis R. Rodriguez: Add new regulatory infrastructure for wireless. (July 28, 2008)

Architecture-specific

• Jason Wessel: mips kgdb support rev 2. (July 28, 2008)

• Peter Oruba: x86: AMD microcode patch loading support. (July 28, 2008)

• Suresh Siddha: x86, xsave: xsave/xrstor support. (July 29, 2008)

Security-related

• David Howells: Introduce credentials [ver #2]. (July 28, 2008)

Virtualization and containers

• Serge E. Hallyn: user namespaces: introduction. (July 28, 2008)

• Serge E. Hallyn: introduce sys_restore. (July 28, 2008)

• Rusty Russell: lguest patches. (July 29, 2008)

Miscellaneous

• Stephen Hemminger: iproute2 v2.6.26. (July 28, 2008)

• Hugh Blemings: Device Tree Mailing List. (July 28, 2008)

• Hans de Goede: Announcing libv4l 0.3.8. (July 30, 2008)

Page editor: Jonathan Corbet

Distributions

News and Editorials

Debian Lenny is frozen

The Debian project is gearing up for the release of Debian Lenny, the next stable release of the Debian GNU/Linux operating system. This week we heard that Debian Lenny has been frozen.

What does the freeze mean and when can we expect Debian Lenny to be released? To answer the second question first, the release is currently expected in September. While the testing branch is very close to what Debian Lenny will be, there are still Release Critical bugs to squash and other work that must happen before Lenny is pronounced stable. This Debian "lenny" Release Information page gives some pointers to various progress pages where you can find out more about the bugs that still need to be fixed.

Mostly what the freeze means is that there are no more automatic uploads from Debian's unstable branch to the testing branch. Most Debian packages start out in unstable, also known as sid. That gives people a chance to test the packages and report any bugs. Assuming that these packages are working well, they will be automatically uploaded to the testing branch after a certain amount of time. Now though, testing is frozen, so a release manager will need to evaluate each unstable package and manually upload the package to testing, if it is judged suitable for Lenny. Chapter 5.13.3 of the Debian developers reference covers direct updates to testing, if you are looking for more detailed information.

When Debian releases a stable distribution the user can be assured that they are getting a very stable operating system. All the packages will interact well with one another. It will not be the most up-to-date system available, because stability is considered more important than new versions of packages. Many Debian users agree. Some will continue to run Etch, the current stable version, until several months after Lenny is released.

If you want a stable system, but need just one or two more current packages, you might consider building those packages yourself. Backports.org is another way of getting a few more current packages for your stable system. AptPinning allows you to run certain packages from one version, say unstable, on your stable system. There will be some risk with each of these methods, as newer packages may require newer libraries or have other dependencies. The more you change your stable system, the more instability you introduce.

The lenny package list will help you find out what packages are currently in Lenny. Some digging through the sections there will show that Lenny includes linux-image-2.6-486 (2.6.25+14), dpkg (1.14.20) and hal (0.5.11-2) are among the Administration Utilities. The Python section lists python (2.5.2-1) among the many related packages. To find out if Lenny has want you are looking for, just browse through the sections.

Comments (4 posted)

New Releases

Foresight 2.0.4 released and introducing the Foresight GNOME Lite Edition

The Foresight project has announced the Foresight GNOME Edition 2.0.4. This release features a brand new theme, and a number of minor updates and bug fixes, notably a problem when trying to install on certain RAID setups. Also available for the first time is the Foresight GNOME Lite Edition.

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Mandriva Linux 2009 Beta 1 released

Mandriva has announced the release of Mandriva Linux 2009 Beta 1 'thornicrofti'. "This beta includes the newest release of KDE 4, KDE 4.1 final (with initial implementation of the Mandriva Ia Ora theme, although this is not yet complete), and GNOME 2.23.5. It also uses Firefox 3 by default, and kernel 2.6.26 final."

Comments (none posted)

Red Hat Enterprise Linux 4.7

Red Hat has announced the release of RHEL 4.7. "Red Hat Enterprise Linux 4 is now marching toward the Production 2 life cycle phase - formerly known as the 'Transition' or 'Deployment' phase. From this point forward, the amount of change introduced for Red Hat Enterprise Linux 4 minor releases is decreasing constantly as Red Hat focuses its efforts on addressing continued stabilization of the release." New stuff includes Firefox 3, a new intrusion detection package, "SystemTap production support," and more. See the release notes for details.

Comments (3 posted)

Alpha releases from openSUSE and Ubuntu

The first openSUSE 11.1 alpha release has been announced, "but beware, this is an Alpha with very rough edges!" There does not appear to be much information posted (beyond the roadmap on what's in 11.1.

Ubuntu, meanwhile, has released the third Intrepid Ibex alpha. See this page for more information on the alpha3 release.

Comments (none posted)

Distribution News

Debian GNU/Linux

Debian Lenny frozen

Debian's upcoming stable release, codenamed Lenny, has been frozen. New versions or new packages will need compelling reasons to get added to the release. Click below for the full announcement with more information on what the freeze means.

Full Story (comments: 24)

Fedora

Unofficial Fedora FAQ Updated for Fedora 9

The Unofficial Fedora FAQ has been updated for Fedora 9. "For this update, I reviewed and revised almost every single question in the FAQ to be up-to-date and even simpler than before. Of course the new FAQ contains an updated yum configuration, and also working Java plugin instructions, but it also has a whole bunch of other small improvements!"

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The results are in for the Fedora 10 naming

And the codename for Fedora 10 is .... Cambridge.

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Gentoo Linux

Council meeting summary for 24 July 2008

Click below for a summary of the July 24 meeting of the Gentoo Council. Topics include whether the user relations project has the authority to enforce the code of conduct on users and extent of code-of-conduct enforcement in general.

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Mandriva Linux

Happy 10th birthday Mandriva

Mandriva Linux is celebrating its 10th birthday. LWN's announcement for the new Linux-Mandrake is dated July 23, 1998. Conectiva is coming up on 13 years according to Wikipedia.

Full Story (comments: none)

Red Hat Enterprise Linux

What's next in Red Hat Enterprise Linux (part 1) (Red Hat Magazine)

Red Hat Magazine looks forward to the next major RHEL release, noting that it looks a lot like what's in Fedora now. "For the administrator, however, PolicyKit opens up a wealth of new possibilities. This can be seen in the 'Authorizations' tool in the System Preferences menu. If I choose 'Setting the system time', we can see the authorization I just used. I can edit it, or add new authorizations for other users. I can even add implicit authorizations-for example, I could set it so that any user in an active console session can reset the clock."

Comments (3 posted)

Distribution Newsletters

Ubuntu Weekly Newsletter #101

The Ubuntu Weekly Newsletter for July 26, 2008 covers: Intrepid Alpha 3 release, MOTU school sessions, Ubuntu screencasts, LoCo team approvals, Global Bug Jam, Ubuntu Massachusetts press release, Colombian team activity, Launchpod episode #8, New Forums staff members, Forums tutorial, Full Circle Magazine #15, and much more.

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OpenSUSE Weekly News/32

This issue of the OpenSUSE Weekly News covers the openSUSE 11.0 Survey, openSUSE 11.0 PromoDVD, openSUSE 11.1 Alpha1 is Available, Bugzilla: Changed Definitions, One Year of openSUSE News, Andrew Wafaa: Lug Radio Live 2008 Report, and much more.

Comments (none posted)

Gentoo Monthly Newsletter

The July issue of the Gentoo monthly newsletter covers the 2008.0 release, Gentoo at Peel Fresco Music Lounge and more.

Comments (none posted)

Fedora Weekly News Issue 136

The Fedora Weekly News for July 26, 2008 looks at FESCo Election Results, Fedora 10 Alpha Freeze, Announcing the Fedora OLPC Special Interest Group, Fedora Unity releases updated Fedora 9 Re-Spin, Feature Process Improvements, plus Planet Fedora articles and much more.

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DistroWatch Weekly, Issue 263

The DistroWatch Weekly for July 28, 2008 is out. "There's been a lot of activities in distribution releases this past week and a bit in developmental releases as well - openSUSE and Ubuntu developmental versions created a bit of buzz around the Web. In the news this week the Mandriva distribution celebrates 10 years, Foxconn Electronics has angered Linux users, and openSUSE is giving away PromoDVDs. Steven Lake is back with us again this morning with a look at NimbleX 2008, I took Parted Magic for a wee spin, and Caitlyn Martin dissects VectorLinux 5.9 SOHO in Reviewed Last Week."

Comments (none posted)

Newsletters and articles of interest

Red Hat Ups Length Of Top Technical Support For Enterprise Linux (InformationWeek)

InformationWeek reports on Red Hat's plans to extend support for Red Hat Enterprise Linux. "Red Hat on Wednesday said it is extending the first phase of its product lifecycle support for Enterprise Linux, when the most technical support resources are made available, from three years to four. That means that new hardware coming out at any time during the first four years of an Enterprise Linux lifecycle will be supported. That "full support" phase previously only lasted for three years. Any release of Enterprise Linux is given a seven-year lifecycle of support, but the level of support drops back in the fifth year, then is reduced further in the sixth and seventh years."

Comments (none posted)

Interviews

Interview with Helio Chissini de Castro - Mandriva (How Software is Built)

How Software is Built talks with Helio Chissini de Castro, a Brazilian developer working for Mandriva. "I work now as a KDE developer, and at the same time, I do debug consulting for a GIS company called ECOS. So, I'm a full time employee of Mandriva, working mainly on open source applications, mostly desktop and KDE."

Comments (none posted)

Page editor: Rebecca Sobol

Development

MARS and The Cell Broadband Architecture

This article is based on a talk given by Geoff Levand at the Linux Symposium in Ottawa on July 24, 2008.

The latest TOP500 Supercomputers list was released last month and the new front-runner is using a processor quite unlike what you would find in your laptop.

The Cell Broadband Architecture (simply referred to as "Cell" in this article) was produced as a joint venture between IBM, Toshiba and Sony. The Cell is available in server hardware but is most commonly found in Sony's Playstation 3 gaming console.

The Cell is interesting because of its unusual design and performance characteristics. The Cell is described as a heterogeneous multicore CPU. It has one Power Processing Element (PPE) which is a general purpose processor and up to 8 Synergistic Processing Elements (SPEs). An SPE is a high-performance vector processing unit with 256KiB of local memory and its own DMA unit. The PPE, SPEs and memory and I/O controllers are connected by a high speed bus.

The PPE is quite slow compared to modern processors so the SPEs must be used to achieve good performance. This means writing software that takes the Cell's design into consideration because there is no simple way to optimize existing applications. Once an application has been designed to use the Cell's SPEs effectively it may run many times faster than when run on a traditional CPU.

GCC with the Cell SDK can emit code for both the PPE and SPEs, including passing messages and managing overlays when the SPE code size exceeds 256KiB. The Linux kernel can also manage multitasking the SPEs with its scheduler. These conveniences make it easier to write code for the Cell processor, but they can have a significant impact on performance. Preemptive multitasking on an SPE involves swapping all the local memory of the current process with the local memory of the process to be run. This requires time and bus bandwidth for the processor. Ideally you would always have at least as many SPEs as processes you need to run so that your process would never be swapped out.

The Multicore Application Runtime System (MARS) framework is a prototype of a cooperative multitasking system for the Cell that tries to address the performance overhead of running many processes on the Cell's available SPEs. MARS uses a library on the PPE and a very small kernel on the SPEs.

MARS currently has a priority-based cooperative scheduler. This scheduler lets you specify how much context you need to save when your process is swapped out. In the "run complete" case no context needs to be saved allowing the next process to run much more quickly.

Synchronizing of processes is commonly required between the Cell's SPEs and PPE. The only way to synchronize with the existing Cell SDK is to cause your SPE to busy-wait on a semaphore, but the MARS scheduler gives you the option of swapping out a process and doing other work instead.

Cooperative multitasking does have its downsides. You lose protection between your processes, and one process could hang and require intervention to release the PPE. It is also necessary to place manual yield points through your code or design each process to be short-lived. However, if your application needs to make the most of the Cell architecture, MARS is a promising starting point and addresses the need for a more efficient approach to scheduling.

Comments (13 posted)

System Applications

Database Software

Benetl 2.2 is out

Version 2.2 of Benetl has been announced. "Benetl is a free ETL for files using postgreSQL 8.3 In this version, a mature one for production mode, bring a new transformation engine."

Comments (none posted)

Jaybird 2.1.6 released (Critical)

Version 2.1.6 of Jaybird, a JCA/JDBC driver suite for the Firebird DBMS, has been announced. "Due to critical fixes in JDBC-108 and JDBC-119, everybody using Jaybird versions between 2.1.2 and 2.1.5 is advised to upgrade to this new version to avoid data corruption when doing updates via ResultSet.updateRow() when the table has a composite primary key. Cases where table's primary key has only one column or there is no primary key at all are not affected."

Comments (none posted)

PostgreSQL Weekly News

The July 27, 2008 edition of the PostgreSQL Weekly News is online with the latest PostgreSQL DBMS articles and resources.

Full Story (comments: none)

Networking Tools

ehcp: version 0.27 released (SourceForge)

Version 0.27 of ehcp ("easy hosting control panel") has been announced, it adds many new features. "ehcp for Ubuntu designed for hosting of multiple domains on single machine. Its aim:easily installable, e.usage, non-complex, functional. homepage:http://www.ehcp.net * automatically installs and works: dns, apache, mysql, ftp, email, domains".

Comments (none posted)

IPCop: 1.4.21 released (SourceForge)

Version 1.4.21 of IPCop has been announced. "IPCop is a friendly firewall solution protecting networks running on linux. It will be geared towards home and SOHO users. Interface is task based. Hardware requirement could be very minimal and grow with services used. 1.4.21 is a maintenance release to fix minor issues found after 1.4.20 publication."

Comments (none posted)

Zenoss Core: 2.2.3 Now Available (SourceForge)

Version 2.2.3 of Zenoss Core has been announced. "Zenoss Core is an enterprise network and systems management application written in Python/Zope. Zenoss provides an integrated product for monitoring availability, performance, events and configuration across layers and across platforms. We are very pleased to announce that the latest stable release of Zenoss, version 2.2.3 is now available for download. The Zenoss team has been hard at work nailing down defects (80+ closed!) and 2.2.3 should be one of our finest releases yet. While this is primarily a maintenance release, a lot of work has gone into testing and improving upgrades and installations."

Comments (none posted)

Printing

Common UNIX Printing System 1.3.8 announced

Version 1.3.8 of the Common UNIX Printing System (CUPS) has been announced. "The new release fixes some performance and printing bugs."

Comments (none posted)

Web Site Development

Django 1.0 alpha released

Version 1.0 alpha of the Django web development platform has been announced. "This release includes all of the major features due for inclusion in the final Django 1.0, though some lower-priority items are still scheduled to be included before the 1.0 feature freeze, which will occur with the first beta release next month."

Comments (none posted)

PyHP: 1.0.0 alpha 2 has been released (SourceForge)

Version 1.0.0 alpha 2 of PyHP has been announced. "PyHP is an Apache module which embeds the Python language inside web pages. PyHP 1.0.0 alpha 2 has been released. This version includes PDF documentation of all the commands and objects included in PyHP and some fixes in DB module. The official home page has been updated to, you can have a look at: http://www.pyhp.org. PyHP is the Python Hypertext Preprocessor, a way to embed server side python scripts inside HTML very similar in philosophy to PHP."

Comments (none posted)

Desktop Applications

Audio Applications

Development Plan for Jokosher 0.10

A new Development Plan has been posted for the Jokosher audio editor project. "Last Sunday we concluded the IRC meeting, and we decided on a list of things to do for the 0.10 release. We decided for certain that the release will be in August. The tentative release date is August 14th, 2008. All features must be completed by the end of July, or they will not be included in the release."

Comments (none posted)

Rivendell v1.0.0rc4 announced

Version 1.0.0rc4 of Rivendell has been announced. Changes include a bug fix and a database update. "Rivendell is a full-featured radio automation system targeted for use in professional broadcast environments. It is available under the GNU General Public License."

Full Story (comments: none)

Desktop Environments

GARNOME 2.23.5 announced

Version 2.23.5 of GARNOME, the GNOME testing distribution, is out. "This is the fifth development release on our trip to GNOME 2.24, which will be out in September."

Full Story (comments: none)

GNOME Software Announcements

The following new GNOME software has been announced this week:

• Banshee 1.2 (new features and bug fixes)
• cairo-compmgr 0.2.0 (new features and code rewrite)
• cluttermm 0.7.2 (support for clutter 0.8)
• GNOME Commander 1.2.7 (new features and bug fixes)
• gnome-control-center 2.23.5 (new features, bug fixes and translation work)
• Gnome Hearts 0.3 (new features, bug fixes and translation work)
• gnome-mud 0.11 (new features, code rewrite and translation work)
• gnome-settings-daemon 2.23.5 (new features and bug fixes)
• gstreamermm 0.9.6 (new features, bug fixes and documentation work)
• GVFS 0.99.3 (bug fix)
• LibUnique 1.0.0 (first stable release)
• Nemiver 0.6.0 (new features, bug fixes and translation work)
• PyGObject 2.15.2 (new features)
• Swfdec 0.6.8 (bug fixes and compatibility improvements)
• Swfdec 0.7.4 (new features and bug fixes)

You can find more new GNOME software releases at gnomefiles.org.

Comments (none posted)

KDE 4.1 released

The KDE 4.1 release is available. "KDE 4.1 is the first KDE4 release to contain the Personal Information Management suite KDE-PIM with its E-Mail client KMail, the planner KOrganizer, Akregator, the RSS feed reader, KNode, the newsgroup reader and many more components integrated into the Kontact shell. Furthermore, the new desktop shell Plasma, introduced in KDE 4.0, has matured to the point where it can replace the KDE 3 shell for most casual users." See the announcement for details and lots of screenshots.

Comments (32 posted)

KDE Software Announcements

The following new KDE software has been announced this week:

• audiokonverter 5.8-beta (new features)
• aKu 1.0 beta1 (new features and bug fixes)
• Amarok 2.0-a2 (new features and bug fixes)
• CSudoku 0.3 (unspecified)
• KAlarm 2.0.1 (bug fixes and translation work)
• KCheckGMail 0.5.7.5 (bug fixes and translation work)
• KDE3TO4 0.0.3 (unspecified)
• Kicad 2008-07-16 (new features and bug fixes)
• KIPCalc 0.9.6 (unspecified)
• konqil.icio.us 2.5 (bug fix)
• KOVpn 0.3-pre7 (bug fixes)
• NoteFinder 3.0.8 (new features)
• qsfm Quick Soundfont Manager 0.9.9rc2 (new features and bug fix)
• rospell 2007.02 (new features, bug fixes and translation work)
• seiko 0.1 (initial release)
• SMILE 0.4.4 (new feature and bug fixes)
• SMILE 0.5.0 (new features, bug fixes and translation work)
• SMILE 0.5.1 (bug fixes and translation work)
• Soprano 2.1.1 (documentation work)
• sqliteman 1.2.0 (new features and bug fixes)
• uRSSus 0.2.0 (unspecified)
• Xt7-Player 0.6b (unspecified)
• Zhu3D 4.1.0 (new features and bug fixes)

You can find more new KDE software releases at kde-apps.org.

Comments (none posted)

Xorg Software Announcements

Xorg Software Announcements The following new Xorg software has been announced this week:

• inputproto 1.4.4 (code cleanup)
• xf86-video-intel 2.4.0 (new features and bug fixes)
• xpyb 0.9 (initial release)

More information can be found on the X.Org Foundation wiki.

Comments (none posted)

Desktop Publishing

LyX 1.5.6 is released

Version 1.5.6 of LyX, a GUI front-end to the TeX typesetter, is out. "This is the fifth maintenance release in the 1.5.x cycle that has been started exactly one year ago. The aim of this release was to make LyX even more robust and to solve some long-standing annoyances. Also, further translation efforts have been made, and LyX now ships in 23 languages. All users are encouraged to upgrade to this version."

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Electronics

XCircuit 3.4.30 released

Stable version 3.4.30 of XCircuit, an electronic schematic drawing application, has been announced. "XCircuit-3.4 is considered the current stable distribution version. Version 3.5 was branched off of this version as the new development branch, and further changes to the 3.4 branch will only reflect necessary bug fixes."

Comments (none posted)

Financial Applications

SQL-Ledger 2.8.17 released

Version 2.8.17 of SQL-Ledger, a web-based accounting system, has been announced. Changes include: "added option to process recurring transactions anytime. fixed formatting error for payments when amounts > 1000 and numberformat set to other than NA format. added item lookup on order/invoice forms."

Comments (none posted)

Interoperability

Wine 1.1.2 announced

Version 1.1.2 of Wine has been announced. Changes include: "Control panel improvements and new appwiz panel. Restructurations of state handling in Direct3D. Support for timer queue functions. Many MSXML improvements. Several fixes to Solaris support. Various bug fixes."

Comments (none posted)

Mail Clients

Thunderbird 2.0.0.16 is available for download

Version 2.0.0.16 of the Mozilla Thunderbird mail client has been announced. "As part of Mozilla Corporation's ongoing stability and security update process, Thunderbird 2.0.0.16 is now available for Windows, Mac, and Linux for free download from http://getthunderbird.com. We strongly recommend that all Thunderbird users upgrade to this latest release."

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Multimedia

Elisa Media Center 0.5.3 released

Version 0.5.3 of the Elisa Media Center, which was examined on LWN last week, has been announced, it adds a number of new capabilities and bug fixes. "This mail announces the release of Elisa Media Center 0.5.3 codenamed "Attraction"."

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Office Suites

Go-oo - a true OpenOffice.org fork?

The longstanding ooo-build project would appear to have matured into a project called Go-oo, and that, in turn, increasingly looks like a fork of OpenOffice.org. "We believe that copyright assignment to a single corporate entity opens the door for substantial abuse of the best-interests of the codebase and developer community. As such, we prefer either eclectic ownership (cf. Mozilla, GNOME, KDE, Linux), or an independent, meritocratic foundation (cf. Eclipse, Apache) to own the rights." See this page for Go-oo features not (yet) found in OpenOffice.org.

Comments (20 posted)

Speech Software

Speex 1.2rc1 is out

Version 1.2rc1 of the Speex speech CODEC has been announced. "This release adds support for acoustic echo cancellation with multiple microphones and multiple loudspeakers. It also adds an API to decorrelate loudspeaker signals to improve multi-channel performance. In the bugfix department, there are fixes for a few bugs in the echo canceller, jitter buffer and preprocessor. At this point, the API for 1.2 should be stable and only a few very minor additions are planned."

Comments (none posted)

Video Applications

bliptv.reader V1.0 released

The initial release (version 1.0) of bliptv.reader has been announced. "bliptv.reader is a Python wrapper around the API of video hosting service blip.tv. It gives you easy access to shows and episodes and many properties of them. Of course you can also easily access the actual video files including their filesize and dimensions."

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Web Browsers

Firefox 3.1 Alpha 1 now available for download

Firefox 3.1 Alpha 1 has been announced. "The first developer milestone of the next release of Firefox - code named Shiretoko Alpha 1 - is now available for download. Shiretoko is built on pre-release version of the Gecko 1.9.1 platform, which forms the core of rich internet applications such as Firefox. Please note that this release is intended for developers and testers only."

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Languages and Tools

HTML

cssutils 0.9.5 final released

Version 0.9.5 final of cssutils, a Python package to parse and build CSS Cascading Style Sheets, has been announced. "0.9.5 had been in development for about half a year and this is the first *final* release for quite some time now - actually the last has been 0.6 ... It is nevertheless definitely not perfect but tests have been expanded, included scripts should all work and all examples on the website have been checked."

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Python

PyBindGen 0.9 released

Version 0.9 of PyBindGen has been announced. "PyBindGen is a Python module that is geared to generating C/C++ code that binds a C/C++ library for Python. It does so without extensive use of either C++ templates or C pre-processor macros. It has modular handling of C/C++ types, and can be easily extended with Python plugins. The generated code is almost as clean as what a human programmer would write."

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Python-URL! - weekly Python news and links

The July 28, 2008 edition of the Python-URL! is online with a new collection of Python article links.

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Miscellaneous

Project dune: 1.6.1 released (SourceForge)

Version 1.6.1 of Project dune has been announced. "Project Dune is a software project management tool to manage your estimates, project information, issues, releases, scrum tasks, timesheets and test execution results. See the project site at projectdune.org for detailed features. This release of the project fixes a couple of bugs and has a couple of new features, mostly user interface improvements."

Comments (none posted)

Page editor: Forrest Cook

Linux in the news

Recommended Reading

Christmas Comes In July For An Open ATI (Phoronix)

Phoronix reports on developments with ATI Radeon R500 support. "This kernel mode-setting support is currently being housed in separate code branches, but will be merged to master and enter the Linux kernel in the future. David Airlie mentioned in the Radeon IRC channel that the Radeon KMS support will hopefully be merged right behind the Intel KMS support, but before that of course will be GEM going to master. David also hops to ship this ATI support with the Fedora 10 Beta."

Comments (21 posted)

Trade Shows and Conferences

Ubuntu Founder Plans to Rival Macintosh with Linux Desktop (Palluxo.com)

Palluxo.com covers an OSCON talk by Canonical's Mark Shuttleworth. "Mark Richard Shuttleworth, CEO of Canonical Ltd and a founder of Ubuntu Foundation, spoke at the O’Reilly Open Source Convention earlier this week. He announced plans to compete with Apple and talked about development of the Linux desktop (Ubuntu OS), as well as the integration of Linux into mobile development. He sees Linux and Windows linked up together., “Linux is the platform of the future. But I think it’s essential that we learn how to work with Windows.”"

Comments (1 posted)

Companies

Linux smartphone axed (the Inquirer)

The Inquirer reports that the Access Linux Platform (ALP) smartphone will not be released as planned. "In case you are left wondering what killed the first ALP smartphone, all clues point towards LiMo, the Linux Mobile Foundation and its pet project. The reply came from Edelman, Orange's PR firm, which also told us to contact Samsung and Access directly, but stated: "just so you know the Samsung i800 has been withdrawn. Since the original project was defined back in February there have been a number of advances in mobile technology.""

Comments (1 posted)

Re-jigged Intel mobile Linux stack dumps Ubuntu (The Register)

The Register notes Intel's change of Linux distribution on its Moblin mobile device platform. "Intel's project to put a Linux and open source stack on mobile devices is getting overhauled to attract developer support, having failed to generate much interest. A year after launching Moblin, Intel plans a second version of its open source stack in the next three weeks, sporting a new operating system, middleware, tools and graphical user interface (GUI). Under the changes, the existing Ubuntu-based kernel is out and Fedora is in, along with a set of Gnome-compatible mobile components that updates Moblin's previous Gnome implementation." (Thanks to Rahul Sundaram).

Comments (1 posted)

Microsoft to sponsor the Apache Software Foundation (ars technica)

ars technica reports that Microsoft will be contributing $100,000 annually to the Apache Software Foundation. "Microsoft's interest in funding Apache projects is likely driven by consumer demand for interoperability. A growing number of companies are deploying Apache-based technologies on top of Windows servers. Microsoft's understanding of enterprise open source adoption is evolving and the company has slowly been taking steps to foster its own community of Windows-based open source software developers."

Comments (20 posted)

Interviews

Interview with Helio Chissini de Castro (How Software Is Built)

How Software Is Built interviews Mandriva's Helio Chissini de Castro. "Sean: Would you tell me a little bit about how Mandriva’s maintained? ... Helio: Our repository, our packages, and everything we do centralizes in the supervisional server. it’s one of the largest supervisional servers ever–around a hundred gigabytes of database. It has the history of all packages and patches and branches and solutions, and it’s open for everyone that’s using the computers, so they can see what is changing in every part, every time. The most amazing thing is that you can easily port and push patches and make it available for everyone without having the harsh part of, “OK, You need to pick the package that others wish and unpack it and see what is inside and then do the patch and apply for it.” It’s open, and it’s easy to see." (Thanks to Adam Williamson).

Comments (none posted)

Interview: Michael Meeks (der Standard)

der Standard interviews Michael Meeks, desktop architect at Novell; the main topic is OpenOffice.org. "In terms of [Sun] reducing contribution: Yeah I think they still have a bunch of engineers on OpenOffice.org - but they are fewer than they were, it's clear that they are redeploying people internally. And that's fine, Sun can do with it's resources as they like, you can't criticize that per se. But the sad thing is their failure to build a community around it, getting other people involved. And that's tied to Sun owning OpenOffice.org. It's a Sun project. They own all of the code, they demand ownership rights, and that just really retards developer interest."

Comments (none posted)

Red Hat's new CEO aims Linux at the cloud (News.com)

Here's an interview with Red Hat CEO Jim Whitehurst on News.com. "As a company gets more sophisticated, one can argue the value of the support is less, but as companies get more sophisticated, the importance of the thing we provide goes up. So for instance, if Amazon wants to get something upstream into the (Linux) kernel because they need some functionality for EC2 (the Elastic Compute Cloud Web service), who can get it upstream? We can."

Comments (7 posted)

Reviews

Linux-friendly Beagle fetches $150 (LinuxDevices)

LinuxDevices looks at the Beagle board, a 3-inch-square board with ARM's Cortex A8 and TI's OMAP3 architectures. "Jason Kridner, director of open system design at TI, says the Beagle board offers a very user-friendly way to explore the capabilities of the A8 architecture, as well as the C64x DSP, for which a free compiler and open source codecs are available. For development on-the-go, the board can be powered by a laptop's USB port, and it comes with an "unbrickable" boot ROM, he observed. "There are four boot options supported in the OMAP ROM itself. The default is to boot from NAND flash, MC/SD, USB, then serial. But, the 'user' button boots from NAND flash last," Kridner said."

Comments (11 posted)

KDE 4.1 delivers a next-gen desktop Linux experience (ars technica)

ars technica reviews KDE 4.1. "The initial doubts and skepticism I experienced when using 4.0 are completely gone. This is, frankly, what 4.0 should have been. The question now is whether users who were burned by the inadequacies of the 4.0 release will give KDE 4 a second chance."

Comments (8 posted)

Will freedom ring on LiMo's Linux-based mobile platform? (ars technica)

Over at ars technica there is a look at the LiMo mobile phone platform based on some comments by ACCESS open source director David Schlesinger at OSCON. "Schlesinger noted that LiMo's dependence on community-driven technologies gives open source software contributors a unique opportunity to take an active role in shaping the platform. He encouraged those who are interested to work directly with the GNOME Mobile and Embedded community. LiMo's 'unique collaboration between commercial and community interests,' he said, 'allows developers to participate in architecting the platform itself.'"

Comments (none posted)

Miscellaneous

The open source jobs boom (InfoWorld)

InfoWorld covers on the improving open-source job market and examines an O'Reilly report on the subject. "Looking for a good job in IT? Sharpen your knowledge of open source development frameworks, languages, and programming. A just-published study of available IT jobs found that 5 percent to 15 percent of the positions now on the market call for open source software skills. Written by consultant and author Bernard Golden in conjunction with O'Reilly Media, the 50-page report attempts to document the spread of open source in the enterprise. Although the study did not quantify the actual percentage of open source products used in the enterprise, the strong growth in available jobs -- in a period when overall IT job growth may be slowing -- points to a surprising breadth of adoption. Indeed, the recession may be pushing budget-strapped IT execs to examine low-cost alternatives to commercial software."

Comments (none posted)

Page editor: Forrest Cook

Announcements

Non-Commercial announcements

NPR Launches Open API

The US National Public Radio organization has announced the launch of an open API for sharing news content. "This launch represents one of the first comprehensive Open APIs introduced by a major national media organization. It is also the latest step in NPR’s multifaceted digital media strategy, which has included expansion of the NPR.org site, NPR Podcasts, the NPR Music destination site and NPR Mobile on-demand services."

Comments (none posted)

Commercial announcements

CodeWeavers announces CrossOver Games 7.1.0

CodeWeavers has announced the release of CrossOver Games 7.1.0. "This new version is largely an incremental improvement; it fixes a range of bugs in a number of games. It also includes a full merge with the Wine 1.0 code base, so this is now a 'post Wine 1.0' version of CrossOver Games."

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Likewise Open Fall 08 announced

Likewise Software has launched Likewise Open Fall 08, a Cross-Platform Authentication and Administration system "A new version of a free, open source software application from Likewise Software enables administrators to remotely and uniformly manage all network computers, regardless of their operating systems, from a single point of control from virtually any computer. Likewise Software today announced Likewise Fall 08, which supports more than 118 platforms. Building on the success of the current version, this new edition includes features that further streamline the process of integrating Linux, Unix and Mac systems into a Microsoft Active Directory environment".

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Mandriva and Precedent Technologies to launch TechSurfer desktop

Mandriva and Precedent Technologies have announced plans to produce the $399 TechSurfer desktop machine. "Mandriva and Precedent Technologies ("PTech"), announce a new partnership, working together on the release in September in the United States of a new low-cost desktop, with Intel Atom CPUs and Mandriva Linux preinstalled on these machines."

Comments (none posted)

Opera joins the Open IPTV Forum

Opera Software has announced that it has joined the Open IPTV Forum. "This global organization is comprised of key IPTV and TV stakeholders working to produce end-to-end specifications to take the next generation of IPTV services into the mass market. As a part of the Forum, Opera will team up with other members, such as Samsung, Ericsson, Sony and Philips, to help create an end-user mass market for IPTV by developing specifications."

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VIA picks up Harald Welte

VIA Technologies has announced that it has contracted with Harald Welte to be its liaison with the open source community. "Harald will assist VIA to develop drivers that are in line with the standards and best practices of Linux kernel development, enhance the quality and public availability of VIA documentation, and improve interaction with the Open Source development community." VIA's start with the community has been a bit on the rough side, so this would appear to be a good move on their part. (See also: Harald's weblog entry on this announcement).

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New Books

JavaScript: The Missing Manual--New from O'Reilly

O'Reilly has published the book JavaScript: The Missing Manual by David McFarland.

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Open Source in the Enterprise--An O'Reilly Radar Report

O'Reilly has announced the publication of a new Reilly Radar Report entitled Open Source in the Enterprise by Bernard Golden.

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Resources

ActiveState Code (the new Python Cookbook) launched

The Python Cookbook has a new home. ActiveState has launched a site for sharing code recipes and moved over the recipes from their earlier site. The new site uses tags to categorize the recipes which is meant to make it easier to browse for code of interest. A bit more information can be found in the announcement linked below.

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Contests and Awards

Martin von Löwis receives 2008 Frank Willison award

Martin von Löwis has received the 2008 Frank Willison Award. "Martin von Löwis continues to be a tireless worker on behalf of the Python community. He has been a long-term contributor to the Python core, and regularly answers questions on both the python-dev list and the comp.lang.python newsgroup. A PSF director since 2002 he was also the prime mover in transitioning the Python development infrastructure from SourceForge, and has created several Roundup issue trackers for various areas."

Comments (none posted)

White Camel Awards 2008 (use Perl)

use Perl has announced the winners of the 2008 White Camel Awards. "jmcada writes "The White Camel Awards for 2008 were just presented at OSCON. This year's winners are Jacinta Richardson, Tatsuhiko Miyagawa, and Gabor Szabo. The winners have all made significant contributions to the Perl community. Congratulations to the winners!""

Comments (none posted)

Education and Certification

Public Python Class - Washington DC - September 2008

Holden Web is will hold its third public "Introduction to Python" class near Washington DC on September 9-11, 2008.

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Event Reports

OLS Proceedings 2001-2008 now available

All of the papers presented at Ottawa Linux Symposium over the last eight years are now available in one place. In addition, the last six years of GCC Summit Proceedings are available there as well.

Comments (4 posted)

Calls for Presentations

make art 2008 call for projects extended

The call for projects for make art 2008 has been extended to August 8. "Make Art is an international festival dedicated to the integration of Free/Libre Open Source Software (FLOSS) in digital art. The third edition of make art - OpenOS - will take place in Poitiers (FR), from the 24th to the 30th of November 2008. make art offers performances, presentations, workshops and an exhibition, focused on the blurred line between art and software programming."

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Upcoming Events

Firebird Conference 2008

The schedule has been posted for the 2008 Firebird Conference. The event takes place in Bergamo, Italy on September 25-27, 2008.

Comments (none posted)

RailsConf Europe taps into vibrant and rich Rails scene

The schedule for RailsConf Europe has been posted. "Co-presenters O'Reilly Media and Ruby Central have unveiled the program for RailsConf Europe, the official trusted event for the Rails Community in Europe on 2-4 September, 2008, in Berlin, Germany. Organizers have extended early registration until 30 July, offering community members the chance to save up to €150."

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Events: August 7, 2008 to October 6, 2008

The following event listing is taken from the LWN.net Calendar.

Date(s)	Event	Location
August 3 August 9	DebCamp 2008	Mar del Plata, Argentina
August 4 August 7	LinuxWorld Conference & Expo	San Francisco, CA, USA
August 9 August 16	Akademy 2008	Sint-Katelijne-Waver, Belgium
August 9 August 17	Linuxbierwanderung (Linux Beer Hike)	Samnaun/Compatsch, Switzerland
August 10 August 16	Debian Conference 2008	Mar del Plata, Argentina
August 11 August 15	SAGE-AU'2008	Adelaide, Australia
August 12 August 14	Flash Memory Summit	Santa Clara, CA, USA
August 13 August 15	YAPC::Europe 2008	Copenhagen, Denmark
August 18	Debian Day	Buenos Aires, Argentina
August 19 August 24	SciPy 2008 Conference	Pasadena, CA, USA
August 20 August 22	Jornadas Regionales de Software Libre	Buenos Aires, Argentina
August 23 August 24	FrOSCon 2008	Saint Augustin, Germany
August 26 August 29	WebGUI Users Conference 2008	Madison, WI, USA
August 27 August 30	Drupalcon Szeged 2008	Szeged, Hungary
August 28 August 30	Utah Open Source Conference 2008	Salt Lake City, UT, USA
September 2 September 4	RailsConf Europe 2008	Berlin, Germany
September 5 September 7	FUDCon Brno 2008	Brno, Czech Republic
September 6 September 7	DjangoCon 2008	Mountain View, CA, USA
September 7 September 10	Workshop on Open Source Software for Computer and Network Forensics	Milan, Italy
September 7 September 14	Python Game Programming Challenge	Online,
September 8	Encontro Nacional de openSUSE	Porto, Portugal
September 9 September 11	EFMI STC 2008	London, England
September 12 September 14	The UK Python Conference	Birmingham, England
September 15 September 18	ZendCon PHP 2008	Santa Clara, CA, USA
September 15 September 16	Linux Kernel Summit 2008	Portland, OR, USA
September 16 September 19	Web 2.0 Expo	New York, NY, USA
September 17 September 19	The Linux Plumbers Conference	Portland, OR, USA
September 18 September 19	Italian Perl Workshop	Pisa, Italy
September 19 September 20	Maemo Summit 2008	Berlin, Germany
September 20	Celebrating Software Freedom Day in Riga, Latvia	Riga, Latvia
September 22 September 25	Storage Developer Conference 2008	Santa Clara, CA, USA
September 23 September 25	4th International Conference on IT Incident Management and IT Forensics	Manheim, Germany
September 24 September 25	OpenExpo 2008 Zürich	Winterthur, Switzerland
September 25 September 27	Firebird Conference 2008	Bergamo, Italy
September 26 September 27	PGCon Brazil 2008	Sao Paulo, Brazil
September 26	Far East Perl Workshop 2008	Vladivostok, Russia
September 26 September 28	ToorCon Information Security Conference	San Diego, CA, USA
September 27 September 28	WineConf 2008	Bloomington, MN, USA
September 29 October 3	Netfilter Workshop 2008	Paris, France
September 29 September 30	Conference on Software Language Engineering	Toulouse, France
September 30 October 1	BA-Con 2008	Buenos Aires, Argentina
October 1 October 3	Vision 2008 Embedded Linux Developers Conference	San Francisco, USA
October 2 October 3	ekoparty Security Conference	Buenos Aires, Argentina
October 3 October 4	Open Source Days 2008	Copenhagen, Denmark
October 4	PyArkansas 2008	Central Arkansas, USA
October 4 October 5	Texas Regional Python Unconference 2008	Austin, TX, USA

If your event does not appear here, please tell us about it.

Mailing Lists

New Linux Audio Tuning mailing list

The Linux Audio Tuning mailing list has been launched. "A new mailing list has been set up to help GNU/Linux distribution maintainers and other interested users share information on performance tuning matters, especially with regard to audio and real-time Linux kernels."

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Page editor: Forrest Cook