It took a long time to get all the parts of the Xen support into the Linux kernel. While rudimentary Dom0-support was available since 2.6.38, support for device backends were missing. It was possible to replace this backend with a userspace implementation included in qemu, but I never tested that. With Linux 3.0, both the traditional block backend and the network backend are available. They are already enabled in the current 3.0-rc3/-rc4 packages in experimental, so the packages can be used as Dom0 and run guests. Right now the backend modules are not loaded, so this still needs some work. Neither the init scripts loads them, because the names where in flux the last time I laid hand on it, nor does the kernel themself expose enough information to load them via udev. I think using udev to load the modules is the way to go. This step marks the end of a five year journey. Around 2.6.16 the Xen people started to stay really close to Linux upstream. With the 2.6.18 releas this stopped and the tree was pushed in different states into Debian Etch and RHEL 5. After that, Xen upstream ceased work on newer versions completely, only changes to the now old 2.6.18 tree where done. SuSE started a forward port of the old code base to newer kernel versions and Debian Lenny released with such a patched 2.6.26. Around that time, minimal support for DomU on i386 using paravirt showed up and Lenny had two different kernels with Xen support. Since 2.6.28 this support was mature and works rather flawless since. Somehow after that, a new port of the Dom0 support, now using paravirt, showed up. This tree based on 2.6.32 is released with Debian Squeeze. After several more rounds of redefining and polishing it is now mostly merged into the core kernel. I don't know what the future brings. We have two virtualization systems supported by Linux now. The first is KVM that converts the kernel into a hypervisor and runs systems with help of the hardware virtualization. The later one is Xen that runs under a standalone hypervisor and supports both para- and hardware virtualization. Both works, KVM is easier to use and even works on current System z hardware. It can be used by any user with hopefully enough margin of security between them. Xen's home is more suited for servers, where you don't have users at all. Both have advantages and disadvantages, so everyone have to decide what he needs, there is no "one size fits all".

Second speaker at today'sseminar,Vladimir Mojica. He is talking about th legal backing for DRM and TPM as well as laws against circumvention. He quotes USA's DMCA as one of the most complete, advanced and forward-minded laws,inviting the audience to push for such a law here. I hope he gets to my (written)question, as today is a very important day in this regard: The Senate has requested the presidency to reject signing the ACTA treaty!
[Update] The Senate is sending Resolution agreeing to prompt the Federal Executive Power titular to instruct the State Secretaries and other dependencies involved in the Anti-Counterfeiting Trade Agreement not to sign said agreement, as it would hinder free interchange of legal material. It also mentions the ISPs should not become de-facto authorities to define when an intellectual/intangible properties right violation is in course, and that it would be unacceptable for ISPs to monitor the users' activities in the net, or to analize the content of the IP packets. Very good news, in a document very well made, in a precise, legal and coherent(!) way.

Excuse me in advance for any typos. itting in a dark room and posting with a Kindle has its down sides. I have been participating for about 1.5 years on a seminar about the copyright in the ediyorial ambit. This year, the focus is on digital media. Today the first speaker is Dr. Kyoshi Tsuru, General Director of BSA Mexico. He is talking about the beauties and advantages of DRM and TPM. It was interesting to hear how he began by saying how people are afraid of nice, good, protective measures and call it with derogatoey, morally charged ways:Specifically about "self-utelage"measures. It is interesting t hear him in the role I often speak eg. by repeating that piracy is a derogatory,morally charged term for "making illegal copies" Fun to hear how he defends that mainly academicians are disconnected from the real world...

Come to the Portland Debian SOCIAL SCENE. There will be beer and flannel for all. Join us as we hack on software to promote the supremity of Cascadia! Note: neither beer nor flannel guaranteed

The office is located not too far from a church (dutch) which contains a fully-functional carillon. For one thing, this means that during day hours, once every fifteen minutes the bells play a little bit of music; for another, it also means that once every so often, someone sits behind the carillon's keyboard, and plays some live music. This is often done in the afternoon between 14:00 and 15:00 on weekdays, when I'm at work. I've grown to like this. Usually the music is classic carillon music; but quite often they add in something unexpected. Today, for example, I was surprised to hear a carillon version of Nothing Else Matters, which sounded surprisingly nice. I've been thinking off and on to place a microphone on the roof of the office, so that I could stream the carillon concerts to the Interwebz. It hasn't happened yet, mainly because it would require me to get organized a bit more than I currently am, but perhaps I might actually go through with it at some undeterminate point in the future... oh well.

When the programming language Python came out while it seemed like an interesting idea, I didn t really see the point. I already know Perl, PHP and C (plus a few others) why learn another language? So until recently, I didn t Recent frustrations with PHP and how loose it is with things like variables made me have another look at Python and what it could do for me. As just learning a language by itself it pretty boring I decided to write some small programs in the language and used the framework Turbogears to do it. First of all, learning the basics of python from perl or PHP is dead simple. The idea of what a language looks like is not too different between these three so it was a snap to write simple stuff in python. So, what does yet-another language give me?

• Variables must be defined before being used, but assigning them defines them too. This is a nice compromise between PHP where you can check undefined variables and C where it all must be defined first, or else.
• try and except. For code that might fail, use try and then catch the error in except. We ve all been guilty of using the @ symbol in PHP to supress stupid error messages, this does it correctly.
• No PHP extract() or compact(). Actually just no extract function is good enough. That function is pure evil.
• Sqlalchemy A proper you look after the database and ill play with objects database extraction layer thingamy. I don t want to play with databases just let me write code and thats what sqlalchemy does well.
• Testing Turbogears uses nosetests which does functional and unit testing. I do get some annoying artifacts based upon testing but generally its all good.
• Python has help() everywhere and pydoc on the command line. Not sure what variable foo can do? Just type help(foo) or even stick it in your script.
• paster! You can run a development site off the command-line using a simple sqlite database. Don t like it, dump the DB and reinstall it with one command.

It s not one-way though, there have been some challenges. Quite likely these are more my deficiencies than the languages.

• Error messages take up a whole screen and often make it difficult to isolate. It s not quite 10-screens-full ala Eiffel but sometimes the error messages tell you something is going wrong, but not what. Mess up your object versus database table references and you get something rather obscure.
• When is an integer not an integer? The answer is, sometimes. Sometimes they work, sometimes they break. It s probably more to do with what pysnmp is doing with them.
• Documentation some is great, some is downright misleading. It comes down to the writer of the documentation for modules. At least it doesn t have well get round to it like some functions in PHP on their website. Documents that say you can directly iterate dictionaries were another dead-end I wandered down. If you are stuck here, add a .items() at the end of it.
• Deployment. It s not just a matter of taring the files up and sticking them into /var/www/sitename and you re done. There are probably good reasons why, but its just annoying.

Despite the minor problems, python really does give you much much more than PHP and some more than Perl. For me and what I am intending on writing it is worth learning yet another language.

Related articles

• A Python programmer s first impression of CoffeeScript (ssokolow.com)
• Guido van Rossum: 21 Years of Python (perspectives.mvdirona.com)
• Which language next? (sfmlcoder.wordpress.com)
• Python vs. Perl vs. C++ Python is Better (strombergers.com)

I just pushed Iceweasel 5.0 to Debian experimental. Why not unstable, some will ask? Well, because we still need to give some time after a first notice before breaking plenty of packages (Thanks to Julien Cristau for the MBF, by the way). I also discontinued the Iceweasel 4.0 backport for Squeeze, as Iceweasel 4.0 won t be receiving security updates. Speaking of security updates, 3.6.18 was also made available on mozilla.debian.net for Wheezy, Squeeze and Lenny. However, I still have to backport the necessary patches to 3.5 in Squeeze and 3.0 in Lenny. My real life schedule wasn t compatible with the security release schedule, so I got late on the security backport train. In the coming weeks, there will also be some additional changes to the mozilla.debian.net repository, but I ll give more details when that happens.

forked-daapd v0.17 is out; the main purpose of this release is to add support for libav 0.7. There are also a few bugfixes that made it into this release, but nothing earth-shattering. One More Thing You ll notice an extra tarball and tag in this release, both marked 0.17gcd. With this release, the GCD (Grand Central Dispatch / libdispatch) codebase is making its debut. libdispatch replaces libevent and allows for greater concurrency inside forked-daapd. This makes forked-daapd snappier, which shows when using Remote or a SoundBridge. The filescanner also benefits from this; it now scans several directories concurrently, reducing the time needed for a rescan by making better use of the machine resources. Thanks to Mark Heily s efforts on libdispatch/libkqueue/libpthread_workqueue over the past year, we now have a Linux version of libdispatch that works well enough to support forked-daapd. This codebase will become the primary codebase for forked-daapd once the database performance issue will be fixed. After this point, the current libevent 1.4 codebase will be legacy and won t see any further development (we ll discuss bugfixes in due time). This new codebase comes with new requirements:

• the Clang compiler from the LLVM project is required, due to the use of the C Blocks extension that isn t supported by GCC;
• libdispatch, of course, is required;
• libtre is a new dependency for concurrent regexps;
• glibc 2.13+ is required, or any glibc version containing a fix for glibc BZ#10563.

libdispatch and its dependencies are available in Debian unstable; it s best and easier to use whatever is in unstable, instead of mixing and matching the libdispatch/libkqueue/libpthread_workqueue versions until they all work together. Due to platform support in Clang, the GCD codebase can only be built for and will only run on i386 and amd64, as far as Linux is concerned. Other architectures will have to wait until support for them is added to Clang. FreeBSD is untested and will probably require some modifications to work; recent enough versions of FreeBSD have a native pthread_workqueue implementation and do not need libpthread_workqueue. Packages are available in experimental for Debian users; they ll end up in unstable in a few weeks, before the libevent2 migration happens there. Tarballs available at http://alioth.debian.org/~jblache/forked-daapd/ ; GPG signatures made with my Debian key F5D65169.

For some time, code documentation for phpMyAdmin had no official place. The reason for this was phpdoc eating way too much memory on daily runs, so I've disabled the cron job. Today I gave a try to DocBlox and it seems to work fine, so I've re-enabled daily builds. The new (daily updated) documentation is available at same location as the original one was: http://www.phpmyadmin.net/phpdoc/ You can also check build failures in the build.log: http://www.phpmyadmin.net/phpdoc/build.log

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John Atherton sent me a link to cyberunions discussing open-source and worker co-ops. In general, it s a very good show and worth a listen by anyone from the union movement, in my opinion. It s available in Ogg as well as MP3, which I think is also a plus point. There were a couple of points where I was ranting at the radio, though The first was the choice to try Skype alternatives. Leaving aside the danger of playing the alternatives game, I can understand why they chose that (the change of corporate control to Microsoft has been in the headlines recently and the phones affect them but not their listeners or readers), but open internet phones are a bit fiddly because they try to move quite a lot of data (audio) in real-time and a lot of domestic network devices don t behave correctly with the protocols that they use to do it. I agree with their conclusion that the problem is probably networking, but I wonder why they didn t log in to their routers, look at any debugging output and try to find the setting to change? Or try switching on debugging in the software and see what s wrong, or send it to someone who can help? Instead, it seemed like Linphone and Ekiga got blamed for not doing Skype-style router-busting without asking. They don t mention whether they tried switching on the STUN option mentioned in the Linphone FAQ and I don t see a email on linphone-users asking for support but I don t read every mail on that list. Am I being unfair, expecting them to seek support? Maybe but I m not sure. If you got the software from a store, what would you do? Would you throw it away and tell people that the stupid thing doesn t work? Moreover, would you use your podcast to say it doesn t work because users need to be clever enough for that obscure tool? That s a great way to scare people off unnecessarily. Wouldn t you usually think you might be overlooking some detail and ask for support, from its maker or the place where you got it? I think you d ask. I d probably ask, even though I m available for hire to fix FOSS problems and it s not the proudest feeling when I have a script-reading call-centre worker solve my mistake. Of course, with most from-store software, you ve paid an artificially-inflated box price, but the bigger cost is your time and that s the same for downloaded free and open source software, so why give it less of a chance to work? I also think they had easier options, like switching more of their website over to free and open source software, like getting rid of the rubbish comment system which doesn t work if you don t let it run javascript on your browser. I ve had a bit of discussion with them since the show and it seems my first suggestion may no longer work (typical!), so we ll see how that goes. Back to the show: the next segment did a good job of linking FOSS to the co-operative movement. I really think they should call it Free and Open Source Software and not just open source because I feel the freedom should be important to the labour movement. Also, calling the whole thing open source seems like calling all of the political left Revolutionary Socialism : inaccurate at best. I don t often express this objection these days (I ve bigger targets to work on), but it s important when trying to inform new audiences, else they only see part of our rainbow, a less radical part. Pretty interesting to suggest Orbea bikes as Mondragon s most famous brand. I d pick Eroski or Caja Laboral. What about you? Then it moved on to a pretty good description of UK co-ops, mentioning co-ops that I m a member of (the Co-operative Group) or buy from (John Lewis and Suma). I was surprised that it seemed to stop short and didn t mention any of the co-ops that work with free software, or with any software in fact. Of course, I d love software.coop to be mentioned, but there are other interesting and very different ones like BristolWireless.net and OSAlliance.com. Globally, many of the worker tech co-ops are linked through the tech-coop mailing list. This was the second part where I was shouting at the speakers. After all, Debian is a great voluntary project making a fantastic GNU/Linux distribution, but it is not a worker co-op by a long way and I suspect some of my fellow developers would be horrified to hear that suggested. Why not mention some actual tech worker co-ops? Finally, before the listener feedback, suggestions of tools which union activists could use. There was some minor confusion about exactly which version or name was really FOSS and a surprising claim about openoffice into LibreOffice (I thought Oracle were still screwing that up with Apache s help but I may have missed some news), but it was a good list of door-opening suggestions. I hope some activists will take them up. It seems there s an earlier show about open social networks, which is a topic I ll look at after I finish my series of posts about mailing lists. So, please let me know if you have comments on this show, that show, open social networks or mailing lists which you think I might find interesting, or if there s anything above you d like me to expand upon (or correct often, correct ).

I've been getting strange failures on some architectures for xdotool. xdotool is a library and a command-line tool to allow you to inject events into an existing X11 session. I'm trying to understand (or even to reproduce) these errors so i can fix them. The upstream project ships an extensive test suite; this test suite is failing on three architectures: ia64, armel, and mipsel; it passes fine on the other architectures (the hurd-i386 failure is unrelated, and i know how to fix it). The suite is failing on some "typing" tests -- some symbols "typed" are getting dropped on the failing architectures -- but it is not failing in a repeatable fashion. You can see two attempted armel builds failing with different outputs: The first failure shows [ and occasionally < failing under a us,se keymap (that is, after the test-suite's invocation of setxkbmap -option grp:switch,grp:shifts_toggle us,se):

Running test_typing.rb
Setting up keymap on new server as us
Loaded suite test_typing
Started
...........F..
Finished in 19.554214 seconds.
  1) Failure:
test_us_se_symbol_typing(XdotoolTypingTests)
    [test_typing.rb:58:in  _test_typing'
     test_typing.rb:78:in  test_us_se_symbol_typing']:
<" 12345678990-=~ !@\#$%^&*()_+[] ;:\",./<>?:\",./<>?"> expected but was
<" 12345678990-=~ !@\#$%^&*()_+] ;:\",./>?:\",./<>?">.
14 tests, 14 assertions, 1 failures, 0 errors

The second failure, on the same buildd, a day later, shows no failures under us,se, but several failures under other keymaps:

Running test_typing.rb
Setting up keymap on new server as us
Loaded suite test_typing
Started
..F.F.F.......
Finished in 16.784192 seconds.
  1) Failure:
test_de_symbol_typing(XdotoolTypingTests)
    [test_typing.rb:58:in  _test_typing'
     test_typing.rb:118:in  test_de_symbol_typing']:
<" 12345678990-=~ !@\#$%^&*()_+[] ;:\",./<>?:\",./<>?"> expected but was
<" 12345678990-=~ !@\#$%^&*()_+] ;:\",./<>?:\",./<>?">.
  2) Failure:
test_se_symbol_typing(XdotoolTypingTests)
    [test_typing.rb:58:in  _test_typing'
     test_typing.rb:108:in  test_se_symbol_typing']:
<" 12345678990-=~ !@\#$%^&*()_+[] ;:\",./<>?:\",./<>?"> expected but was
<" 12345678990-=~ !@\#$%^&*()_+[] ;:\",./<>?:\",./<>?">.
  3) Failure:
test_se_us_symbol_typing(XdotoolTypingTests)
    [test_typing.rb:58:in  _test_typing'
     test_typing.rb:88:in  test_se_us_symbol_typing']:
<" 12345678990-=~ !@\#$%^&*()_+[] ;:\",./<>?:\",./<>?"> expected but was
<" 12345678990-=~ !@\#$%^&*()_+ ;:\",./>?:\",./<>?">.
14 tests, 14 assertions, 3 failures, 0 errors

I've tried to reproduce on a cowbuilder instance on my own armel machine; I could not reproduce the problem -- the test suites pass for me. I've asked for help on the various buildd lists, and from upstream; no one resolutions have been proposed yet. I'd be grateful for any suggestions or hints of things i might want to look for. It would be a win if i could just reproduce the errors. Of course, one approach would be to disable the test suite as part of the build process, but it has already helped catch a number of other issues with the upstream source. It would be a shame to lose those benefits. Any thoughts?

As most of the GSoC projects in phpMyAdmin go on quite well, we're already merging some of the new features to our master branch. You can try them all on our demo server and you are welcome to report any issues found :-). First big part which has been changed is rewriting of server status page done by Tyron Madlener. It now provides more information, provides real time charts and much more. This change also included change in charts produced in other places in the code, so they are now more interactive and allow easy exporting. The browse mode got improved as well, you can now reorder columns (by Aris Feryanto) and there are new options for displaying GIS data (by Madhura Jayaratne). While speaking about GIS, I have to mention another new feature - rendering of GIS data, either as polygons or on OpenStreetMap map (you can see it by clicking on "Visualize GIS data" link on browse page, it is not possible to link it directly due to XSS protection). Many smaller changes are being done by Thilanka Kaushalya to convert various parts of user interface to AJAX. And last but not least we have nice support for editing stored procedures and functions. Support for events and triggers will follow soon. All these are being done by Rouslan Placella. I hope you will like these new features and thanks to all our GSoC students who are doing great job.

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Yesterday I became a member of the CNT. Now I just need to buy the tshirt :)

This is a kernel module I cooked in a couple of days. The idea is to expose a v4l device that gets its data from user space.

I had 2 use cases in mind:
1) Educational purpose for myself (I'm really a kernel noob).
2) Streaming movies over skype, google talk, ... etc.

The idea could be good or completely rubbish but hey ? Learning can only be done with stupid ideas!

The code is highly unstable. It shouldn't oops the kernel but I'm not responsible. I've been developing and testing it inside qemu.

Clone it from the git repository via:

Here are a few missing bits off the top of my head:

* I'm not following the kernel coding style yet ;-)
* I'm sure my locking, unlocking and concurrency handling is flawed.
* The code is a bit fragile.
* It'd be nice to implement mmap support for the character device. This should eliminate data copies.
* Perhaps expose the character device all the time and generate "fake" frames when streaming starts ? Problem now is one has to be very fast in feeding data to the module otherwise select() on the v4l device will timeout.
* Many more...

If someone finds this idea useful, please drop me a line.
Comments, use cases, ideas and tips are really welcomed!

If I see a lot of interest, I might try to push it to the kernel tree one day ;-)

Update: Seems vloopback already exists and renders my code useless. I might still do something with it as my idea seems a bit simpler but whatever.

Update 2: There's also v4l2loopback and its fork. read more

I uploaded a new upstream version of the ttf-oldstandard font. The new version is a real 2.2 while the former was numbered 2.02 by upstream but got accidentally numbered 2.2 by us, packagers.. The occasion was good and I renamed the source package to follow the "yes-yes-yes-soon-to-be-published" fonts packaging policy for naming. The new package is "fonts-oldstandard". A new upstream version of samba was released and I packaged it just after the last 3.5.8 package entered testing. Samba is now 3.5.9 in unstable. I should work on backporting (for backport.debian.org) what's entered in testing, by the way. I sent l10n NMU proposals for unattended-upgrades, memtest86+, cacti. I also NMUed memtest86 (still in DELAYED).

After my post about the vector screenshots two days ago stirred quite some interest, I was hard-pressed to push the code out in proper form. So here you are: You can get release tarballs which can be installed with the usual configure && make && sudo make install. You can also get the code via git from the gitorious project page. Freshmeat and ohloh registration will follow soon. I don t think though that I need more infrastructure, e.g. a mailing list would be overkill, unless the project becomes much larger than I expect at the moment. After all, I do prefer small projects.
Over the version that you saw in the screencast two days ago (which almost broke my server, as I included the video via the <video> tag, and every reader of my blog entry automatically started downloading the 2MB file), I have added support for SVG, PostScript and (hear hear) PNG, made the button much more visible and improved minor usability things. Since Saturday, the work was covered in ycombinator s hacker news and on golem.de. If the interest stays high and I get positive feedback from users of the above code, I ll also upload it to Debian. I would really like to have this as a stand-alone program that can take screenshots of any running gtk-3 application, but I m not sure if this is possible in a clean fashion. Can I somehow hook into a running glib application and call object methods there, maybe similar to how gdb would do it? Alternatively, I could install the module system wide, so that it is loaded into every application, and then somehow triggered (e.g. using a signalling mechanism based on X window s property). Ideas and patches welcome!

The upstream and debian packages for psmisc version 22.14 were released tonight. This version has a lot of bugfixes. I ve also taken some time to clean up some of the minor compile warnings I used to get which were mainly variables set but not used. Two bugs that I ll concentrate on getting fixed for the next version are all about the command line. The first is that the fuser -s flag changes the return code for items found. It should be consistent so it doesnt matter if fuser displays values or not, 0 means found something and 1 means didn t find it. I can see why in the code it might be different, because the code follows different paths with the s option, but not exactly where the problem is. The second bug is the -M flag for fuser only works if it is before the mount points so -M -m /foo works but -m /foo -M does not. Unlike the -s problem, I can see where it is failing. Currently fuser scans the options one by one. If it finds a -m option, it checks at that point if the -M option is set. The solution is to store all potential targets and only after exhausting the entire command line do we add the potential targets to our real targets. It means scanning the command line, or a subset of it, twice but the performance penalty is tiny. Finally, I released there was a rather neat Makefile command make distcheck . This target makes a tar.g archive, extracts it, builds then cleans. It is a very good program for trapping things like a file exists in your local directory but is not included in the tar.gz (lists.h was missing until I ran this). For some make distcheck is something they re known for years, but if you have an autotools package you develop, have a look at it. With all the talk about testing and test driven releases, I was going to put some test cases in. The problem is there doesn t seem to be an easy way to do testing. I might have to just hack up some scripts but surely there is a better way. That would trap, for example that fuser -s returns 1 but fuser returns 0. I looked at check, but it doesn t work for single-file programs like psmisc is mainly made of.

Reading the thingiverse blog, I came across two highlights of interesting parts of the Autodesk and Microsoft Kinect End User License Agreements (EULAs), which illustrates quite well why I stay away from software with EULAs. Whenever I take the time to read their content, the terms are simply unacceptable.