I've recently spent five days debugging a problem in obnam, my backup program. It turned out to be a bug in my B-tree implementation, which I wrote for obnam. The process was pretty long, and it might be instructive to de-brief myself. The bug manifested itself when I ran a backup test that was larger than what I had ran before: one terabyte of live data. The symptom was a key lookup problem in a B-tree. Good: the problem was entirely deterministic, and easy to reproduce. Bad: it took hours to reproduce it. My first step was to fiddle with the obnam parameters to see if I could make it fail faster, but in the same way. I got the time down to half an hour. After this, I started fiddling with the code to see if I can figure out what happens, and perhaps find a quick fix to the bug. After some hours, I realized I was being stupid. I was making essentially random changes to the code, instead of hunting down the actual cause. I had no idea what was going wrong, so trying to fix it was an act of utter stupidty. So I went back to where I had started from. The next step was to run "obnam fsck" on the failing backup store. This did not find any problems. The fsck I've written is a bit simplistic, and merely checks that for every client in the backup store, every generation is found, and within every generation each file's metadata, and data chunks are found. I will improve fsck in the future, but right now it was not helpful. I did not have a tool to verify that the actual B-trees were OK. So I wrote one. It, too, is quite simplistic, but at least it proved that the key was still present in the on-disk version of the B-tree. At this point, I did a code review of the B-tree code. It had been a some months since I'd touched the code, and hence the review brought up a bunch of minor issues: outdated comments, badly formatted code, stupid variable names, etc. One or two buglets, too, but nothing relevant to the case of the missing key. At this point I made a mistake: I concluded that the error was not in the B-tree code, but the obnam code using the B-trees. I spent the next couple of days running the test case, adding more logging, and analyzing the results. Without my mistake, I would not have ignored indicators that would have led me faster into the depths of the B-tree code. I might have saved a day or two of the process. Eventually I narrowed down the problem to a single B-tree insertion call in the obnam code. The call inserted a new value for a given key into one tree, and the value in another tree changed as well. Quite mysterious. My B-trees are an implementation of the Rodeh B-trees. All updates are done using copy-on-write, and this allows efficient cloning of trees. However, as an optimization, a node that is used by only one tree at a time can be modified in-place. This speeds things up a lot when the same tree is updated many times. In obnam, each B-tree represents a backup generation. The specific bug I was hunting was that the key I use for storing the unique identifier for a generation changed in two trees at the same time. Now that I have actually found and fixed the problem, it is clear that I should have realized at once what was happening, but I didn't, so I spent another couple of days adding logging statements into the B-tree insertion code, and tracing where things went wrong. Since B-trees are updated quite heavily by obnam, the log files grew quite big, and the test runs grew quite long. The last run I did resulted in a 94 gigabyte log file, and lasted over 12 hours. less had trouble browsing the log file, probaby due to the rather long lines generated by dumps of the B-trees. I ended up splitting the large file into quite a number of small ones, using csplit. After some more analysis, I figured out the problem: the code that shadowed a B-tree node, i.e., implemented the copy-on-write modification, failed to update the reference counts of the children of a shadowed index node. The Rodeh B-trees use lazy reference counts: when an index node is shadowed, only the immediate children get reference count updates. This turns out to work quite well, and saves quite massive amounts of updates. Unfortunately, my code was too lazy, and did not update any reference counts. After I had come this far, it only took a couple of minutes to write a unit test to catch the problem, fix the code, run the unit tests successfully, and commit. Then I ran the big test case again, without the extra logging I had added, and the code worked fine. At least it worked fine for about 24 hours until it ate up all memory in the VM I was running it on, but that's a separate problem. What can I do to prevent this kind of bug happening in the future? Unit testing didn't catch it, and I have 100% statement coverage with unit tests (not counting 19 excluded statements). Code review by other programmers would surely help. I should perhaps attract others to the project. Please excuse the length of this blog post. It is a distillation of the about ten A4-pages' worth of notes I made during this debugging process. (Always make notes when debugging. Your brain can't remember all details.)

It's been a while since I started working on this project and even longer
since I had the idea. It's therefore a pleasure to finally announce the DACA project.


What is DACA?

Automated Code Analysis helps detect and fix bugs and other issues in source
code. The project aims to give users easy access to a wide variety of tools to
improve quality of software distributed by Debian, while giving the tool's
developers a test bed, more visibility, and more feedback.
This is achieved by running those tools on the complete Debian archive.

http://qa.debian.org/daca/

What is there for everyone?

At the moment there are only partial reports from two tools, but the list of
tools to be evaluated and possibly included goes over twenty.

Current tools: cppcheck, and checkbashisms (at the source package level.)

Limitations

Most of the tools are CPU-bound, limiting considerably the number of tools and
time it takes to check the whole Debian archive. For example, with the typical
sid repository update (i.e. not during the freeze and with a working ftp-
master) it is impossible for the server running cppcheck to keep up with all
the changes.

How can you help?

* First of all you can go and squash bugs!
Please keep in mind what's in the notices at the bottom of the pages. They are
rather static now, but they may change later.

* Second, report false positives, fix bugs, improve the tools
Every report page (at the footer) should mention the version of the tool used
to generate it. They are usually the latest.

* Third, join the DACA project
More hands are needed to evaluate other tools, setup an infrastructure for
running them, and finally generating the web reports.
Discussing tools already available at DACA is also welcome.

There's a project request at Alioth pending its approval, but once accepted
access to the repository and mailing lists will be found at:

http://alioth.debian.org/projects/daca

(the contact email address at the DACA website will be updated accordingly)

* Fourth, donate hardware

If you have equipment with very powerful CPUs or other hardware you (or your
company) can donate, please take a look at the following page:

http://www.debian.org/donations#equipment_donations

Note that this may be handled by people unrelated to the DACA project, and as
such you should mention what you would prefer your hardware to be used for.

* And finally, figure out what I missed, provide feedback, and go back to step
one.


Thanks!

By the way, thanks to the DSA team for tolerating a few hiccups on the host running
cppcheck, and to those who previewed the website and provided feedback.

As I'm not currently working on any suitable paper, I'll just post this to my blog so it does not completely slip off my radar ;-) Also, it might be interesting to my reader. Readers? Oh, there are two of you now? Good! Yesterday, I learnt thanks to Beatriz Busaniche that a group of South American Free Culture activists launched number zero of a magazine that promises to be very interesting: Cultura RWX, cultura en modo lectura, escritura y acci n (culture in reading, writing and action mode). Guys, best luck with this new project! Anyway, reading it, I found this asseveration I want to keep at hand:

( )cuando surge la industria musical aparecen los derechos de autor como forma de defensa de los productores musicales, espec ficamente los m sicos. No tanto frente a los usuarios, porque hasta el cassette no existi posibilidad de copiar una obra musical. Era una defensa frente a las discogr ficas, que buscaban cerrar contratos muchas veces abusivos con los artistas. M sica en Libertad: La industria musical frente al cambio de paradigma; Mat as Lennie, adaptaci n: Sebasti n Vazquez

Yes, yes, translating to English:

( )when the musical industry was born, copyright appeared as a means of defense of the musical producers, specifically of the musicians. Not so much against the users, because up until the invention of the cassette there was no possibility to copy a musical creation. It was a defense against the discographic companies, which tried to close often abusive contracts with the artists. Music in Freedom: Musical industry and the paradigm shift; Mat as Lennie, adaptation: Sebasti n V zquez

I have argued (i.e. in here) in this same line regarding the birth of copyright itself It was an arrangement that had to be made between writers and printers, back in the XVI/XVII centuries. Simple individuals were just unable to get anything of value out of the copying technology they had at hand. Copyright was born in a time where reproduction required specialized equipment. Today, massive reproduction technology is a given for a good portion of the planet's population. Copyright now only defends big corporations And will inevitably fade away as anachronic. Of course, it refuses to go without a fight... But it cannot win long-term. We cannot afford to allow it!

Last week I attended the WebKitGTK+ 2010 hackfest. It was a great opportunity to meet up with the other developers, discuss some plans for the future, hack away at WebKitGTK+. But, most importantly, play Street Figher 2 =). Thanks to Collabora and Igalia for sponsoring the hackfest, Igalia for hosting and organizing it (well done!), and the GNOME foundation for having sponsored my trip to Coru a! Unlike last year we didn t find any big design issues hurting our work (page cache, I m looking at you!) on new futures. I also didn t have any huge plans for new API, although we did manage to get some new stuff in there, like the plugins management API Xan created, and the further work done by Dan in soup. This meant, from my point of view the hackfest has been a great oportunity to look at refactorings that we could do to further simplify understanding the code, changing it, and even sharing it =). Besides pushing the debian packaging of the 1.3.x series a bit further. Coru a was great as always, and I enjoyed going around, eating and hacking there, although I got a cold on the last days which kinda hindered my ability to stare at the screen for too long, some times. Now that I m at the hot brazilian summer again I ll hopefully get better soon =) Cheers \o/

I've released libpipeline 1.1.0, and uploaded it to Debian unstable. The changes are mostly just to add a few occasionally useful interfaces:

• Add pipecmd_exec to execute a single command, replacing the current process; this is analogous to execvp.
• Add pipecmd_clearenv to clear a command's environment; this is analogous to clearenv.
• Add pipecmd_get_nargs to get the number of arguments to a command.

The shared library actually ends up being a few kilobytes smaller on Debian than 1.0.0, probably because I tweaked the set of Gnulib modules I'm using.

(This is part of a series of posts on Why Linux?) My first PC was an Amstrad PPC640D; an 8088 with twin 720k 3.5" disk drives. It never ran Windows (3.0 was current at that point in time and I don't think it would manage to run off a single floppy), so ran DOS. I moved on to an 8086 desktop machine, complete with 10M full height 5.25" HDD and CGA graphics. It still runs DOS. From there I moved to an 80386DX-40 desktop, with 4M RAM and SVGA graphics. A massive leap forward, and something actually capable of running more than DOS. Except I didn't. I had a Windows for Workgroups 3.11 install, but mostly I still did what I needed to from DOS. The machine was never networked; it had a modem attached but that was used to connect to Fidonet which was well serviced by DOS tools. I put Linux on the box at one point but it was C and TCP/IP and I was Pascal and Fido in those days, so I didn't really know what to make of it. Fast forward a few years and I'm still mostly using DOS, but I'm on a 486 and am running a separate machine as a BBS. It's using RemoteAccess under DOS and it feels like with 486 hardware I should be able to do some of this multitasking lark. I try OS/2 and Windows 95, but both end up dropping modem data when doing other things (I've moved on to ISDN at this point). Maybe I just needed to tweak things more, but I deem multitasking with BBS software a failure and go back to DOS and 2 machines. When I went to university one of my new course mates had brought a machine running Linux, and various of the older students are already running it. There was a wealth of information and interest available to me. So I try again. I've learnt C and TCP/IP networking since last time, and suddenly it all makes more sense and I'm able to do more with it (I'm sure a summer using HP/UX on my desktop at Nortel helped). And, as I finally get to the point, it's efficient. It makes use of the extra memory in the machine that DOS can only touch with kludges. It allows me to multitask in a usable fashion. I don't feel the need for a GUI so I don't have to run one, which no doubt helps, but everything that's running is easily visible and tunable. I start running it as my desktop at university and convert the BBS over to it at some point soon after. It doesn't drop modem data. I rejoice, and don't look back. In those days I was running hardware that was probably at the low end of what the popular multitasking OSes wanted (I remember seeing Win95 on a 4M machine when it first came out, and it crawled). These days my main machines are (I would hope) more than capable of running Windows well. The efficiency angle is still an appeal of Linux though; for example in the server space I don't understand why you'd want to run something with the overhead of an always on GUI (people who leave Linux servers running GDM confuse me). I want to be able to do everything I need on a server remotely, be that via SSH or, in a pinch, a serial console. I don't want to sit at the box and use a GUI. Linux lets me run only what I actually need on the machine.

The two first interviews were dedicated to long-time Debian developers. This time I took the opposite approach, I interviewed David Kalnischkies who is not (yet) a Debian developer. But he s contributing to one of the most important software within Debian the APT package manager since 2009. You can already see him in many places in Debian sharing his APT knowledge when needed. English is not his native language and he s a bit shy, but he accepted the interview nevertheless. I would like to thank him for the efforts involved and I hope his story can inspire some people to take the leap and just start helping My questions are in bold, the rest is by David. Who are you? I am David Kalnischkies, 22 years old, living in the small town Erbach near Wiesbaden in Germany and I m studying computer science at the TU Darmstadt. Furthermore I am for more than half a decade now young group leader of my hometown. I never intended to get into this position, but it has similarities with my career in this internet-thingy here. I don t remember why, but in April 2009 I was at a stage that some simple bugs in APT annoyed me so much that I grabbed the source, and most importantly I don t know why I did it but I published my changes in Mai with #433007, a few more bugs and even a branch on launchpad. And this public branch got me into all this trouble in June: I got a mail from Mr. package managment Michael Vogt regarding this branch A few days later I joined an IRC session with him and closely after that my name appeared for the first time in a changelog entry. It s a strange but also addicting feeling to read your own name in an unfamiliar place. And even now after many IRC discussions, bugfixes and features, three Ubuntu Developer Summits and a Google Summer of Code in Debian, my name still appear in places I have never even thought about e.g. in an interview. What s your biggest achievement within Debian? I would like to answer MultiArch in APT as it was my Google Summer of Code project, but as it has (not much) use for the normal user at this point will hopefully change for wheezy I chose three smaller things in squeeze s APT that many people don t even know yet:

• MMap run out of room , the most famous error related to the APT::Cache-Limit option is gone. The DynamicMMap in APT now deserves its name
• Download and usage of multiple Translations of Descriptions
• crazy stuff like apt-cache show ^apt-.*$/experimental works

If your impression is now that I only do APT stuff: that s completely right, but that s already more than enough for me for now as the toolchain behind the short name APT contains so many tools and use cases that you always have something different. You re an active member of the APT development team. Are there plans for APT in Debian Wheezy? What features can we expect? That s very hard to answer, as the team is too small to be able to really plan something. I mean, you can have fancy plans and everything and half a second later someone arrives on the mailing list with a small question which eats days of development time just for debugging But right now the TODO list contains (in no particular order):

• MultiArch managing packages built for different architectures like i386 on amd64 to ease the usage of packages which only work on specific architectures or cross-compiling.
• rewriting the subsystem responsible for downloading files to e.g. enable tools like apt-file or debtags to reuse the infrastructure by plugging into it.
• splitting long descriptions out of the Packages file to possibly decrease the size to download on an apt-get update . Includes mostly pulling the button only to enable it by the archive masters
• backporting popular features of some frontends to enable all frontends to use them, e.g. apt-get changelog or apt-get download
• support research on resolver improvements by implementing support for a distribution independent upgrade problem format (CUDF).
• an additional single binary for users wrapping apt-get, apt-cache and co.
• getting in contact (again) with various forks like apt-rpm and derivatives like maemo or telesphoreo to join forces instead of splitting them by working on different (and possibily very old) heads of the dragon

We will see what will get real for wheezy and what is postponed, but one thing is sure: more will be done for wheezy if you help! If you could spend all your time on Debian, what would you work on? I would spend it on APT s debbugs count zero would be cool to look at! We make progress in this regard, but with the current velocity we will reach it in ten years or so. Reading more mailing lists would be interesting, as I am kind of an information junky. Maintaining a package could be interesting to share the annoyance of a maintainer with handcrafted dependencies just to notice that APT doesn t get it in the way I intended it to be. Through, to make it feel real I need to train a few new APT contributors before so they can point my mistake out, but this unfortunately doesn t depend so much on time but on victims Maybe I could even be working on getting an official status. Beside that, I would love to be able to apt-get dist-upgrade the increasing mass of systems I and many others carry around in their pockets. In regards to my phone, this is already fixed, but there is much room for improvements. What s the biggest problem of Debian? You need to be lucky. You need to talk at the right time to the right person. That s not really a debian-only problem as such, but in a global project full of volunteers you can see it clearly as there are plenty of opportunities to be unlucky. For example, it s unlikely that an interview would be made with me now if Michael had not contacted me in June 2009. In a big project like Debian, you are basically completely lost without a mentor guiding you, so things like the debian-mentors list are good projects, but I am pretty certain they could benefit from some more helping hands. The other thing which I consider a problem is that and I read from time to time some people don t care for translations. That s bad. Yes, a developer is able to read English, otherwise s/he couldn t write code or participate on the mailinglists. Still, I personally prefer to use a translated application if I have the chance as it s simply easier for me to read in my mother tongue, not only because I am dyslexic, but because my mind still thinks in German and not in English. Yes, I could personally fix that by thinking in English only from now on, but its a quite big problem to convince my family which is not really familiar with tech-stuff to use something if they can t understand what is written on screen. It was hard enough to tell my mother how to write an SMS in a German interface. My phone with English words all over the place would be completely unusable for her despite the fact that my phone is powered by Debian and better for the task from a technical point of view. You are not yet an official Debian developer/maintainer, but you re already perceived in the community as one the most knowledgeable person about APT. It s a great start! What s your advice to other people who want to start contributing to Debian in general, and to APT in particular? It was never a goal in my life to start contributing . My goal was and still is to make my life easier by letting the computer work for me. At some point APT hindered the success of this goal, so it needed to be fixed. I didn t expect to open pandora s box. So, my advice is simple: Just start. Ignore the warning signs telling you that this is not easy. They are just telling you that you do something useful. Only artificial problems are easy. Further more, contribution to APT, dpkg or any other existing package is in no way harder than opening an ITP and working on your own, and it s cooler as you have a similar minded team around you to talk to. APT didn t accept release codenames as target release was one of the first things I fixed. If I had asked someone if that would be a good starting point the answer would have been a clear no , but I didn t search for a good starting point As a kid I can start playing football by just walking on the field and play or I can sit near the field, watching the others play, while analyzing which position would be the best for me to start ruling out one by one as the technical requirements seem too high Oh bicycle kick that sounds complicated I can t do that Julian Andreas Klode is working on a APT replacement, there s also Cupt by Eugene V. Lyubimkin. Both projects started because their authors are not satisfied with APT, they find APT s code difficult to hack partly due to the usage of C++. Do you share their concerns and what s your opinion on those projects? I don t think C++ is a concern in this regard, after all cupt is currently rewritten to C++0x and APT2 started in vala and is now C + glib last time I checked at least. I personally think that something is wrong if we need to advertise an application by saying in which language it is written The major problem for APT is probably that the code is old : APT does its job for more than 12 years now, under different maintainers with an always changing environment around it: so there are lines in APT which date from a time when nobody knew what a Breaks dependency is, that packages can have long descriptions which can be translated or even that package archives can be signed with a gpg key! And yet we take all those for granted today. APT has proven to adapt to these changes in the environment and became in this process very popular. So I don t think the point is near (if it will come at all) that APT can go into retirement as it is completely replaced by something else. The competitors one the other hand have their first 12 years still to go. And it will be interesting to see how they will evolve and what will be the state of the art in 2022 But you asked what I think about the competitors: I prefer the revolution from inside simply because I can see effects faster as more users will profit from it now. Cupt and co. obviously prefer the normal revolution. The goal is the same, creating the best package manager tool, but the chosen way to the goal is different. aptitude and cupt have an interactive resolver for example: that s something I dislike personally, for others that is the ultimate killer feature. cupt reading the same preference file as APT will have a different pinning result, which we should consider each time someone mentions the word drop-in replacement . APT2 isn t much more than the name which I completely dislike currently from a user point of view, so I can t really comment on that. All of them make me sad as each line invested in boilerplate code like configuration file parsing would be in my eyes better be spent in a bugfix or new feature instead, but I am not here to tell anyone what they should do in their free time But frankly, I don t see them really as competitors: I use the tools I use, if other do that too that s good, if not that s their problem. The thing that annoys me really are claims like plan is to remove APT by 2014 as this generates a vi vs. emacs like atmosphere we don t need. If some people really think emacs is a good editor who cares? I really hope we all can drink a beer in 2022 in Milliways, the restaurant at the end of the package universe, remembering the good old 2010 Is there someone in Debian that you admire for his contributions? No, not one, many! Michael Vogt who has nearly the monopole of package manager maintainer by being upstream of APT, synaptics and software center to name only the biggest and still has the time to answer even the dumbest of my questions. Jason Gunthorpe for being one of the initial developers behind deity who I will probably never meet in person beside in old comments and commit logs. Christian Perrier for caring so much about translations. Obey Arthur Liu as a great admin for Debian s participation in Google s Summer of Code. Paul Wise for doing countless reviews on debian-mentors which are a good source of information not only for the maintainer of the package under review. I guess I need to stop here because you asked for just one. So let s end with some big words instead: I am just a little cog in the big debian wheel

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Thank you to David Kalnischkies for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

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As I mentioned recently, the Ubuntu Technical Board is reviewing the most popular topics in Ubuntu Brainstorm and coordinating official responses on behalf of the project. This means that the most popular topics on Ubuntu Brainstorm receive expert answers from the people working in these areas. This is the first batch, and we plan to repeat this process each quarter. We ll use feedback and experiences from this run to improve it for next time, so let us know what you think. Power management (idea #24782) Laptops are now outselling desktops globally, and laptop owners want to get the most out of their expensive and heavy batteries. So it s no surprise that people are wondering about improved power management in Ubuntu. This is a complex topic which spans the Linux software stack, and certainly isn t an issue which will be solved in the foreseeable future, but we see a lot of good work being done in this area. To tell us about it, Amit Kucheria, Ubuntu kernel developer and leader of the Linaro working group on Power Management, contributed a great writeup on this topic, with technical analysis, tips and recommendations, and a look at what s coming next.

I am going to attempt to summarize the various use profiles and what Ubuntu does (or can do) to prolong battery life in those profiles. Power management, when done right, should not require the user to make several (difficult) choices. It should just work providing a good balance of performance and battery life.

IP address conflicts (idea #25648) IP addressing is a subject that most people should never have to think about. When something isn t working, and two computers end up with the same IP address, it can be hard to tell what s wrong. I was personally surprised to find this one near the top of the list on Ubuntu Brainstorm, since it seems unlikely to be a very common problem. Nonetheless, it was voted up, and we re listening. There is a tool called ipwatchd which is already available in the package repository, and was created specifically to address this problem. This seems like a further indication that this problem may be more widespread than I might assume. The idea has already been marked as implemented in Brainstorm based on the existence of this package, but that doesn t help people who have never heard of ipwatchd, much less found and installed it. What do you think? Have you ever run into this problem? Would it have helped you if your computer had told you what was wrong, or would it have only confused you further? Is it worth considering this for inclusion in the default install? Post your comments in Brainstorm. Selecting the only available username to login (idea #6974) Although Linux is designed as a multi-user operating system, most Ubuntu systems are only used by one person. In that light, it seems a bit redundant to ask the user to identify themselves every time they login, by clicking on their username. Why not just preselect it? Indeed, this would be relatively simple to implement, but the real question is whether it is the right choice for users. Martin Pitt of the Ubuntu Desktop Team notes that consistency is an important factor in ease of use, and asks for further feedback.

So in summary, we favored consistency and predictablility over the extra effort to press Enter once. This hasn t been a very strong opinion or decision, though, and the desktop team would be happy to revise it.

Icon for .deb packages (idea #25197) Building on the invaluable efforts of Debian developers, we work hard to make sure that people can get all of the software they need from Ubuntu repositories through Software Center and APT, where they are authenticated and secure. However, in practice, it is occasionally necessary for users to work with .deb files directly. Brainstorm idea 25197 suggests that the icon used to represent .deb packages in the file manager is not ideal, and can be confusing. Matthew Paul Thomas of the Canonical Design Team responds with encouragement for deb-thumbnailer, which makes the icon both more distinctive and more informative. He has opened bug 685851 to track progress on getting it packaged and into the main repository.

I have reviewed the proposed solutions with Michael Vogt, our packaging expert. Solution #1 is straightforward, but we particularly like solutions #5 and #10, using a thumbnailer to show the application icon from inside each package.

Keeping the time accurate over the Internet by default (idea #25301) It s important for an Internet connected computer to know the correct time of day, which is why Ubuntu has included automatic Internet time synchronization with NTP since the very first release (4.10 warty ). So some of us were a little surprised to see this as one of the most popular ideas on Ubuntu Brainstorm. Colin Watson of the Ubuntu Technical Board investigated and discovered a case where this wasn t working correctly. It s now fixed for Ubuntu 11.04, and Colin has sent the patches upstream to Debian and GNOME.

My first reaction was hey, that s odd I thought we already did that? . We install the ntpdate package by default (although it s deprecated upstream in favour of other tools, but that shouldn t be important here). ntpdate is run from /etc/network/if-up.d/ntpdate, in other words every time you connect to a network, which should be acceptably frequent for most people, so it really ought to Just Work by default. But this is one of the top ten problems where users have gone to the trouble of proposing solutions on Brainstorm, so it couldn t be that simple. What was going on?

More detail in GNOME system monitor (idea #25887) Under System, Preferences, System Monitor, you can find a tool to peek under the hood at the Linux processes which power every Ubuntu system. Power users, hungry for more detail on their systems inner workings, voted to suggest that more detail be made available through this interface. Robert Ancell of the Ubuntu Desktop Team answered their call by offering to mentor a volunteer to develop a patch, and someone has already stepped up with a first draft. Help the user understand when closing a window does not close the app (idea #25801) When the user clicks the close button, most applications obediently exit. A few, though, will just hide, and continue running, because they assume that s what the user actually wants, and it can be hard to tell which has happened. Ivanka Majic, Creative Strategy Lead at Canonical, shares her perspective on this issue, with a pointer to work in progress to resolve it.

This is more than a good idea, it s an important gap in the usability of most of the desktop operating systems in widespread use today.

Ubuntu Software Centre Removal of Configuration Files (idea #24963) One feature of the Debian packaging system used in Ubuntu is that it draws a distinction between removing a package and purging it. Purging should remove all traces of the package, such that installing and then immediately purging a package should return the system to the same state. Removing will leave certain files behind, including system configuration files and sometimes runtime data. This subtle distinction is useful to system administrators, but only serves to confuse most end users, so it s not exposed by Software Center: it just defaults to removing packages. This proposal in Ubuntu Brainstorm suggests that Software Center should purge packages by default instead. Michael Vogt of the Ubuntu Foundations Team explains the reasoning behind this default, and offers an alternative suggestion based on his experience with the package management system.

This is not a easy problem and we need to carefully balance the needs to keep the UI simple with the needs to keep the system from accumulating cruft.

Ubuntu One file sync progress (idea #25417) Ubuntu One file synchronization works behind the scenes, uploading and downloading as needed to replicate your data to multiple computers. It does most of its work silently, and it can be hard to tell what it is doing or when it will be finished. John Lenton, engineering manager for the Ubuntu One Desktop+ team, posts on the AskUbuntu Q&A site with tools and tips which work today, and their plans to address this issue comprehensively in the future. Multimedia performance (idea #24878) With a cornucopia of multimedia content available online today, it s important that users be able to access it quickly and easily. Poor performance in the audio, video and graphics subsystems can spoil the experience, if resource-hungry multimedia applications can t keep up with the flow of data. Allison Randal, Ubuntu Technical Architect, answers with an analysis of the problem and the proposed solutions, an overview of current activity in this area, and pointers for getting involved.

The fundamental concern is a classic one for large systems: changes in one part of the system affect the performance of another part of the system. It s modestly difficult to measure the performance effects of local changes, but exponentially more difficult to measure the network effects of changes across the system.

The bug webinterface of the Ultimate Debian Database currently knows about the following release critical bugs:

In Total:	712
Affecting Squeeze:	256
Squeeze only:	76
Remaining to be fixed in Squeeze:	180

Of these 180 bugs, the following tags are set:

Pending in Squeeze:	10
Patched in Squeeze:	51
Duplicates in Squeeze:	21
Can be fixed in a security Update:	40
Contrib or non-free in Squeeze:	7
Claimed in Squeeze:	3
Delayed in Squeeze:	2
Otherwise fixed in Squeeze:	34

Ignoring all the above (multiple tags possible) 79 bugs need to be fixed by Debian Contributors to get Debian 6.0 Squeeze released. However, with the view of the Release Managers, 174 need to be dealt with for the release to happen. Please see Interpreting the release critical bug statistics for an explanation of the different numbers.

As part of my work for EDF, I ve had to package and integrate a set of tools for performance measurement and profiling of HPC code. This toolbox comprises tools for analysis of both sequential and parallel codes, MPI communications profiling and, of course, visualization frontends. Without going into too much details, here s the list:

• OpenSpeedShop: a complete performance and profiling workbench, including I/O and MPI
• PerfSuite: a relatively simple and easy to use performance analysis toolkit
• TAU: a complete performance analysis framework including automatic instrumentation with PDT
• Scalasca: a tool for performance optimization of parallel codes, including MPI communications
• a number of dependencies: slog2, Open Trace Format libraries, VampirTrace, dyninst, monitor, perfctr, pfmon, PAPI,
• visualization frontends: paraprof, jumpshot4, cube3,

If you ve been anywhere near HPC code, the names probably ring a bell; they re the best tools out there in their category, developed and used by the top laboratories. Over the past year, all the tools have received some level of testing, meaning we know they do work at the very least to some extent. As you can imagine, testing such tools is no easy task and takes an insane amount of time and resources of all kinds. Testing is all the more important that I had to produce a number of patches to integrate the tools properly in the distribution and, in some cases, to even get them to build. Now, we would like to share this work with the HPC community in and around Debian. How exactly we are going to do that isn t clear just yet; most probably, we ll end up building a team with other interested parties and offer our packages as a base to build upon. There are a number of challenges with these tools: they re not easy to build, they re not easy to maintain, they re not easy to use, they re not easy to understand. Basically, nothing is easy. Some of those tools were never meant to be packaged and integrated in a distribution and no sane amount of patching will fix that, so we have to live with packages that aren t quite as polished as we like them to be. And then, there are licenses. Some tools are non-free due to usage restrictions. Others rely on non-free dependencies. Although I ve been looking at the licenses, a thorough license check will be required and decisions will need to be made. It s not for the faint of heart! If you are interested in these tools and in bringing them to Debian, please get in touch. I ve also had to package the Apache Derby database (Java); if someone out there cares about Derby, I d be more than happy to provide my packages as a start base for getting Derby into Debian. The packages need some work by someone who knows a thing or two about Derby and who can test and enhance the packaging of the server part.

Wow, it's been 3 months since I stopped using flash.

dpkg.log.3.gz:2010-09-14 11:24:35 purge flashplugin-nonfree 1:2.8.1 1:2.8.1

At the time, there were known, open security holes in flash, and Adobe had announced a fix date -- rather far in the future. It made a lot of sense to remove flash at least temporarily. I never found a compelling reason to reinstall it. I've missed out on a small amount of content, and had to do a little more to get at other content. But it's been worth it to not need to worry about flash slowing pages to a crawl, being insecure, bypassing cookie management, and being generally nasty, proprietary software. Between youtube's html5 beta and Vimeo's easy link on every page to switch to html5, I have no trouble seeing most videos. One annoyance is when someone embeds a video somewhere using only the flash player, and also doesn't link to its page -- but I am seeing more youtube embeds being done with html5 recently. Youtube is also still inconsistent with some videos not yet being encoded in html5, and so I have to pull out youtube-dl occasionally to download and watch something. On the audio side, links to sound files are everywhere, and use of html5 <audio> is also very common. The only thing I ever miss is Super Mario Bros. Crossover. I look forward to the day when the only use of flash is to play such historical roms in MAME.

Uh... Holger just pointed me to an error I introduced, when I ported my script to create the rc stats from using the bts.turmzimmer.net interface to the UDD: The Number of bugs for the release managers view did not included bugs fixed in Debian's unstable branch, but still open in it's testing branch. Of course Release Managers are also interested in these bugs, as the packages fixing these bugs need to be migrated to testing (prefered solution) before the release can happen. I just fixed my script, and reviewed the other queries. Seems fine now, so that starting with next fridays stats, everything should be working again. Looking at it with repaired Release Team glasses, that brings us up from 110 bugs to 175 bugs. (And still 72 release critical bugs without known solution). Sorry.

The bug webinterface of the Ultimate Debian Database currently knows about the following release critical bugs:

In Total:	689
Affecting Squeeze:	240
Squeeze only:	87
Remaining to be fixed in Squeeze:	153

Of these 153 bugs, the following tags are set:

Pending in Squeeze:	14
Patched in Squeeze:	53
Duplicates in Squeeze:	20
Can be fixed in a security Update:	20
Contrib or non-free in Squeeze:	6
Claimed in Squeeze:	2
Delayed in Squeeze:	2
Otherwise fixed in Squeeze:	25

Ignoring all the above (multiple tags possible) 72 bugs need to be fixed by Debian Contributors to get Debian 6.0 Squeeze released. However, with the view of the Release Managers, 110 need to be dealt with for the release to happen. Please see Interpreting the release critical bug statistics for an explanation of the different numbers.

(This is a part of a series of posts on my recent experience with Windows; see Windows (I) and Windows (II): User Interface.)

Every GNU/Linux desktop distribution hangs on a package management system as a foundation, and as a result the packaging systems are quite advanced, while Windows is stuck with those pesky installation wizards. There have been several stabs to implement a package system for Windows (see here), but none seem to have caught on.

There are three main disadvantages on not having good package management: tedium of manual installation, no dependency resolution and no system-wide automatic updates. In practice they are less important than it might seem. Installation wizards are indeed tedious, but in terms of time I found them to be quick enough to get through. Moreover, apps tend to be less specialized and more encompassing than Linux utilities, and as a result you do not need to install as many things as in Linux. For the same reason dependency resolution is not as important: there are few dependencies in general. As for automatic updates, most high-profile apps have integrated mechanisms to deal with that, however, I found that those mechanisms tended to result in nagging the user with messages. After a while I started ignoring the update notifications. I suspect that happens to many users.

The one thing that Windows has going for it is simplicity. You download installation binaries and you run them, and that's it. Linux package systems tend to be very complicated, and if (when) they break, you will need serious sysadmin chops to deal with the problem. Also installing specific versions (either older ones, or newer ones not yet available in the distro) of specific apps/libraries can be unnecessarily complicated, and the dependency graph limits your actions. In my experience, Windows does well enough without all this complexity as long as you don't reinstall your system too often.

As for the other complaints, I frequently run into the restriction of moving/editing files opened by another application. Coming from Linux, that one is stupidly annoying. Furthermore, it is frustrating not to be able to move inactive (or stuck) background windows. I really miss my unified filesystem namespace. Also there's quite a bit of nagging in general on Windows which I would rather do without. In the end, these are not dealbreakers though.

In my next (and probably final) post I will discuss software development on Windows.

For my birthday back in October, my wonderful wife gave me a Kindle 3 from Amazon. I d been considering other e-book readers for quite some time, but I had mostly ignored the Kindle due to the lack of EPUB support and a general dislike of Amazon s DRM enforcement. In the end, the superior hardware and ecosystem of the Kindle overpowered those concerns and overall I m very pleased with the purchase. The screen is amazing, literally just like reading off a piece of paper and the selection of books is OK. I ve been buying almost all my books from Amazon to date since it s so easy (the Whispernet is amazingly quick!) but it s not terribly difficult to get EPUBs from elsewhere onto the device after a quick run through Calibre to turn them into a MOBI file, so I keep telling myself I ve still got some flexibility. Almost as much fun as reading on the device has been learning about how it works. The Mobile Read forums have lots of step by step posts on how to do specific tasks like replacing the screensaver image, but they don t give much background detail on how the Kindle is actually operating which is what really interests me. Luckily among all the step by step posts I also found a usbnetwork package which also adds an SSH server to the Kindle, so after installing that and then SSHing in to my Kindle I ve been poking around. Under the cover the Kindle reveals a fairly standard Linux installation. While the hardware and IO devices are obviously unique, compared to something like an Android phone, the Kindle is refreshingly normal . Hardware

• Freescale MX35 ARMv6 based CPU with Java specific instruction support.
• 256MB RAM
• 4GB of internal flash presented as an SDHC device with four partitions. A ~700MB root partition, a ~30MB /var/local partition, another roughly 30MB kernel partition and then the rest (~3.1G) as the writeable user partition where your books and other content are stored. The root and /var/local partitions are ext3! (not jffs or some other more traditional flash based file system) while the user partition is vfat for easy use with Windows, etc.
• The board is code-named luigi and there are lots of references to mario and fiona scattered around the device, and even in some URLs on Amazon s website. Someone was obviously a Super Mario fan.
• The wireless chipset is Atheros based using the ar6000 drivers.
• The WAN (3G) modem presents itself as a USB serial device and is controlled via a custom daemon named wand which uses the standard Linux pppd package to establish IP connections over a private APN Amazon (provided by Vodafone here in Ireland).
• The EInk display shows up as some special files under /proc rather than as a device. With a bit of digging I found some simple constants that when written to the proc files cause the screen to display the standard boot/progress/upgrading images. I haven t deciphered how to make more complex updates to the display yet.

Software

• The kernel is based on Linux 2.6.26, with a bunch of hardware specific patches and drivers from lab126.com, an Amazon subsidiary who appear to be responsible for much of the low-level driver and device development.
• Lots of familiar open source projects are present, e.g. syslog-ng, DBus, busybox, pppd, wpa_supplicant, gstreamer, pango, openssl and the list goes on. You can download all the sources from Amazon s website. I haven t spent any time to see what if anything has been modified.
• There were a few unexpected finds as well such as GDB and powertop! No doubt useful for the developers, but highly unlikely to actually be used on a shipping Kindle.
• Boot-up is controlled by a set of sysv style init scripts which setup the filesystems and then start a handful of daemons to look after the low-level subsystems (network, power, sound) as well as the standard syslog and cron daemons you d expect to see on any Linux box.
• Once the basic system is up and running the init scripts kick off the framework which lives under /opt/amazon/ebook and consists of lots of Java classes. The system uses the cvm Java environment from Sun/Oracle which is specialised for embedded low-memory devices like this. The framework appears to take over most of the co-ordination, management and interaction tasks once it has started up.

The application/framework code is heavily obfuscated apparently using the Allatori Java Obfuscator. The jrename and jd-gui utilities have proven very handy in helping to untangle the puzzle, although they still only leave you with a pile of Java source code with mostly single letter alphabetic variable and class names! I ve been using IntelliJ s support for refactoring/renaming Java code to slowly work through it (thanks in large part to error/log messages and string constants found through the code which can t be obfuscated easily and help to explain what is going on), and I m slowly beginning to piece together how the book reading functionality works. I ll maybe write more on this in a future post. In one of my initial tweets about the Kindle I mentioned that it seemed to be regularly uploading syslog data to Amazon based on some sendlogs scripts I d noticed and a few syslog lines containing GPS co-ordinates that had been pasted on the Mobile Read forums. I can t find any trace of GPS co-ordinates in any syslog messages I ve seen on my device, but there is definitely information about the cell sites that my Kindle can see, the books that I m opening and where I m up to in them:

101206:235431 wand[2515]: I dtp:diag: t=4cfd77b7,MCC MNC=272 01,Channel=10762,Band=WCDMA I IMT 2000,Cell ID=1362209,LAC=3021,RAC=1
,Network Time=0000/00/00 00.00.00,Local Time Offset=Not provided,Selection Mode=Automatic,Test Mode=0,Bars=4,Roaming=1,RSSI=-88,Tx
Power=6,System Mode=WCDMA,Data Service Mode=HSDPA,Service Status=Service,Reg Status=Success,Call Status=Conversation,MM Attach St
ate=Attach accept,MM LU State=LU update,GMM Attach State=Attach accept,GMM State=Registered,GMM RAU State=Not available,PDP State=
Active,Network Mode=CS PS separate attach mode,PMM Mode=Connected,SIM Status=Valid; PIN okay; R3,MM Attach Error=No error,MM LU Er
ror=No error,GMM Attach Error=No error,GMM RAU Error=Not available,PDP Rej Reason=No error,Active/Monitored Sets=0;39;-11 1;180;-1
5,RSCP=-111,DRX=64,HSDPA Status=Active,HSDPA Indication=HSDPA HSUPA unsupp,Neighbor Cells=,Best 6 Cells=,Pathloss=,MFRM=,EGPRS Ind
ication=,HPLMN=,RPLMN=272;01 ,FPLMN=234;33 234;30 234;20 272;05 ,n=1: 101206:235758 cvm[3426]: I Reader:BOOK INFO:book asin=B003IWZZ3Y,file size=233168,file last mod date=2010-11-27 19.18.22 +0000,con
tent type=ebook,length=MobiPosition_ 465747,access=2010-12-06 09.44.32 +0000,last read position=MobiPosition_ 464387,isEncrypted=f
alse,isSample=false,isNew=false,isTTSMetdataPresent=false,isTTSMetadataAllowed=true,fileExtn=azw: 101206:233416 udhcpc[5639]: Offer from server xxx.xxx.2.254 received
101206:233416 udhcpc[5639]: Sending select for xxx.xxx.2.10...
Interestingly you can see from the last two lines, that Amazon has taken some care to preserve privacy by not including the full IP address given to the device by my local Wifi network, so in light of that I find it interesting that they decided not to obfuscate the Cell and Book IDs in those respective log messages too. Seems rather inconsistent. As to how and when these logs are sent to Amazon, the picture is a little bit murky. Every 15 minutes tinyrot runs out of cron and rotates /var/log/messages if it is greater than 256k in size. Rotated logs are stored into /var/local/log under filenames like messages_00000044_20101207000006.gz and alongside the log files are a set of state files named nexttosendfile, messages_oldest, messages_youngest. Something regularly sweeps through this directory to update the state and remove the old logs (after sending them up to Amazon I assume). I suspect that something is buried in the Java application code mentioned above. On the whole the Kindle is a fascinating piece of technology. It delivers a wonderful reading experience on top of a familiar Linux system and is going to provide me with many more hours of entertainment as I unpack all the tricks and techniques that have gone into this device. I would recommended it as a present for geeks everywhere.

I disagree with Lars. Respect needs to be earned. It should not be a default, and it should not be demanded either on one's own behalf or for others, or you are conflating it with something incredibly ignoble. When you do not respect someone, and you show that person respect, you are being deceitful. Of this I disapprove.

The relationship between Debian and Ubuntu has been the subject of many vigorous debates over the years, ever since Ubuntu s launch in 2004. Six years later, the situation has improved and both projects are communicating better. The Natty Narwhal Ubuntu Developer Summit (UDS) featured like all UDS for more than 2 years a Debian Health Check session where current cooperation issues and projects are discussed. A few days after that session, Lucas Nussbaum gave a talk during the mini-Debconf Paris detailing the relationship between both projects, both at the technical and social level. He also shared some concerns for Debian s future and gave his point of view on how Debian should address them. Both events give valuable insights on the current state of the relationship. Lucas Nussbaum s Debian-Ubuntu talk Lucas started by introducing himself. He s an Ubuntu developer since 2006 and a Debian developer since 2007. He has worked to improve the collaboration between both projects, notably by extending the Debian infrastructure to show Ubuntu-related information. He attended conferences for both projects (Debconf, UDS) and has friends in both communities. For all of these reasons, he believes himself to be qualified to speak on this topic. Collaboration at the technical level He then quickly explained the task of a distribution: taking upstream software, integrating it in standardized ways, doing quality assurance on the whole, delivering the result to users, and assuring some support afterward. He pointed out that in the case of Ubuntu, the distribution has one special upstream: Debian. Indeed Ubuntu gets most of its software from Debian (89%), and only 7% are new packages coming from other upstream projects (the remaining 4% are unknown, they are newer upstream releases of software available in Debian but he was not able to find out whether the Debian packaging had been reused or not). From all the packages imported from Debian, 17% have Ubuntu-specific changes. The reasons for those changes are varied: bugfixes, integration with Launchpad/Ubuntu One/etc., or toolchain changes. The above figures are based on Ubuntu Lucid (10.04) while excluding many Ubuntu-specific packages (language-pack-*, language-support-*, kde-l10n-*, *ubuntu*, *launchpad*). The different agendas and the differences in philosophy (Debian often seeking perfect solutions to problems; Ubuntu accepting temporary suboptimal workarounds) also explain why so many packages are modified on the Ubuntu side. It s simply not possible to always do the work in Debian first. But keeping changes in Ubuntu requires a lot of work since they merge with Debian unstable every 6 months. That s why they have a strong incentive to push changes to upstream and/or to Debian. There are 3 channels that Ubuntu uses to push changes to Debian: they file bug reports (between 250 to 400 during each Ubuntu release cycle), they interact directly with Debian maintainers (often the case when there s a maintenance team), or they do nothing and hope that the Debian maintainer will pick up the patch directly from the Debian Package Tracking System (it relays information provided by patches.ubuntu.com). Lucas pointed out that those changes are not the only thing that Debian should take back. Ubuntu has a huge user base resulting in lots of bug reports sitting in Launchpad, often without anyone taking care of them. Debian maintainers who already have enough bugs on their packages are obviously not interested in even more bugs, but those who are maintaining niche packages, with few reports, might be interested by the user feedback available in Launchpad. Even if some of the reports are Ubuntu-specific, many of them are advance warnings of problems that will affect Debian later on, when the toolchain catches up with Ubuntu s aggressive updates. To make this easier for Debian maintainers, Lucas improved the Debian Package Tracking System so that they can easily get Ubuntu bug reports for their packages even without interacting with Launchpad. Human feelings on both sides Lucas witnessed a big evolution in the perception of Ubuntu on the Debian side. The initial climate was rather negative: there were feelings of its work being stolen, claims of giving back that did not match the observations of the Debian maintainers, and problems with specific Canonical employees that reflected badly on Ubuntu as a whole. These days most Debian developers find something positive in Ubuntu: it brings a lot of new users to Linux, it provides something that works for their friends and family, it brings new developers to Debian, and it serves as a technological playground for Debian. On the Ubuntu side, the culture has changed as well. Debian is no longer so scary for Ubuntu contributors and contributing to Debian is The Right Thing to do. More and more Ubuntu developers are getting involved in Debian as well. But at the package level there s not always much to contribute, as many bugfixes are only temporary workarounds. And while Ubuntu s community follows this philosophy, Canonical is a for-profit company that contributes back mainly when it has compelling reasons to do so. Consequences for Debian In Lucas s eyes, the success of Ubuntu creates new problems. For many new users Linux is a synonym for Ubuntu, and since much innovation happens in Ubuntu first, Debian is overshadowed by its most popular derivative. He goes as far as saying that because of that Debian becomes less relevant . He went on to say that Debian needs to be relevant because the project defends important values that Ubuntu does not. And it needs to stay as an independent partner that filters what comes out of Ubuntu, ensuring that quality prevails in the long term. Fixing this problem is difficult, and the answer should not be to undermine Ubuntu. On the contrary, more cooperation is needed. If Debian developers are involved sooner in Ubuntu s projects, Debian will automatically get more credit. And if Ubuntu does more work in Debian, their work can be showcased sooner in the Debian context as well. The other solution that Lucas proposed is that Debian needs to communicate on why it s better than Ubuntu. Debian might not be better for everybody but there are many reasons why one could prefer Debian over Ubuntu. He listed some of them: Debian has better values since it s a volunteer-based project where decisions are made publicly and it has advocated the free software philosophy since 1993. On the other hand, Ubuntu is under control of Canonical where some decisions are imposed, it advocates some proprietary web services (Ubuntu One), the installer recommends adding proprietary software, and copyright assignments are required to contribute to Canonical projects. Debian is also better in terms of quality because every package has a maintainer who is often an expert in the field of the package. As a derivative, Ubuntu does not have the resources to do the same and instead most packages are maintained on a best effort basis by a limited set of developers who can t know everything about all packages. In conclusion, Lucas explained that Debian can neither ignore Ubuntu nor fight it. Instead it should consider Ubuntu as a chance and should leverage it to get back in the center of the FLOSS ecosystem . The Debian health check UDS session While this session has existed for some time, it s only the second time that a Debian Project Leader was present at UDS to discuss collaboration issues. During UDS-M (the previous summit), this increased involvement from Debian was a nice surprise to many. Stefano Zacchiroli the Debian leader collected and shared the feedback of Debian developers and the session ended up being very productive. Six months later is a good time to look back and verify if decisions made during UDS-M (see blueprint) have been followed through. Progress has been made On the Debian side, Stefano set up a Derivatives Front Desk so that derivative distributions (not just Ubuntu) have a clear point of contact when they are trying to cooperate but don t know where to start. It s also a good place to share experiences among the various derivatives. In parallel, a #debian-ubuntu channel has been started on OFTC (the IRC network used by Debian). With more than 50 regulars coming from both distributions, it s a good place for quick queries when you need advice on how to interact with the distribution that you re not familiar with. Ubuntu has updated its documentation to prominently feature how to cooperate with Debian. For example, the sponsorship process documentation explains how to forward patches both to the upstream developers and to Debian. It also recommends ensuring that the patch is not Ubuntu-specific and gives some explanation on how to do it (which includes checking against a list of common packaging changes made by Ubuntu). The Debian Derivative Front Desk is mentioned as a fallback when the Debian maintainer is unresponsive. While organizing Ubuntu Developer Week, Ubuntu now reaches out to Debian developers and tries to have sessions on working with Debian . Launchpad has also been extended to provide a list of bugs with attached patches and that information has been integrated in the Debian Package Tracking system by Lucas Nussbaum. Still some work to do Some of the work items have not been completed yet: many Debian maintainers would like a simpler way to issue a sync request (a process used to inject a package from Debian into Ubuntu). There s a requestsync command line tool provided by the ubuntu-dev-tools package (which is available in Debian) but it s not yet usable because Launchpad doesn t know the GPG keys of Debian maintainers. Another issue concerns packages which are first introduced in Ubuntu. Most of them have no reason to be Ubuntu-specific and should also end up in Debian. It has thus been suggested that people packaging new software for Ubuntu also upload them to Debian. They could however immediately file a request for adoption (RFA) to find another Debian maintainer if they don t plan to maintain it in the long term. If Ubuntu doesn t make this effort, it can take a long time until someone decides to reintegrate the Ubuntu package into Debian just because nobody knows about it. This represents an important shift in the Ubuntu process and it s not certain that it s going to work out. As with any important policy change, it can take several years until people are used to it. Both issues have been rescheduled for this release cycle, so they re still on the agenda. This time the UDS session was probably less interesting than the previous one. Stefano explained once more what Debian considers good collaboration practices: teams with members from both distributions, and forwarding of bugs if they have been well triaged and are known to apply to Debian. He also invited Ubuntu to discuss big changes with Debian before implementing them. An interesting suggestion that came up was that some Ubuntu developers could participate in Debcamp (one week hack-together before Debconf) to work with some Debian developers, go through Ubuntu patches, and merge the interesting bits. This would nicely complement Ubuntu s increased presence at Debconf: for the first time, community management team member Jorge Castro was at DebConf 10 giving a talk on collaboration between Debian and Ubuntu. There was also some brainstorming on how to identify packages where the collaboration is failing. A growing number of Ubuntu revisions (identified for example by a version like 1.0-1ubuntu62) could indicate that no synchronization was made with Debian, but it would also identify packages which are badly maintained on the Debian side. If Ubuntu consistently has a newer upstream version compared to Debian, it can also indicate a problem: maybe the person maintaining the package for Ubuntu would be better off doing the same work in Debian directly since the maintainer is lagging or not doing their work. Unfortunately this doesn t hold true for all packages since many Gnome packages are newer in Ubuntu but are actively maintained on both sides. Few of those discussions led to concrete decisions. It seems most proponents are reasonably satisfied with the current situation. Of course, one can always do better and Jono Bacon is going to ensure that all Canonical teams working on Ubuntu are aware of how to properly cooperate with Debian. The goal is to avoid heavy package modifications without coordination. Conclusion The Debian-Ubuntu relationships used to be a hot topic, but that s no longer the case thanks to regular efforts made on both sides. Conflicts between individuals still happen, but there are multiple places where they can be reported and discussed (#debian-ubuntu channel, Derivatives Front Desk at derivatives@debian.org on the Debian side or debian@ubuntu.com on the Ubuntu side). Documentation and infrastructure are in place to make it easier for volunteers to do the right thing. Despite all those process improvements, the best results still come out when people build personal relationships by discussing what they are doing. It often leads to tight cooperation, up to commit rights to the source repositories. Regular contacts help build a real sense of cooperation that no automated process can ever hope to achieve.

This article was first published in Linux Weekly News. You can get my monthly summary of the Debian/Ubuntu news, all you have to do is to click here to subscribe to my free newsletter.

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As a first step on the road to evaluating different configuration management systems, I set up two VMs to test out puppet. Puppet is conveniently packaged within Debian so client and server installation was very simple. By default, puppet clients will look for a host named puppet on the local network, so by naming the server sensibly the two started talking to each other. puppetca --sign [client hostname] on the server started the ball rolling. My first test configuration was to add a user to the sudoers file. With CF Engine 2, I would have achieved this by using editfiles to check for a regular expression and insert a line if necessary. I stumbled across some CF Engine-style definitions for puppet in a Debian Administration article (taken originally from puppet's own wiki, which have since been moved/deleted) and achieved it using

append_if_no_such_line   sudo:
  file => "/etc/sudoers",
  line => "jon ALL=(ALL) ALL"
 

I'm a little concerned that this approach to problem solving is no better than CF Engine 2, and in fact worse than how I'd do it with CF Engine 2: if the host had a line with a different quantity of whitespace, such as jon ALL=(ALL) ALL, it won't match exactly and a duplicate line will be appended, whereas with CF Engine 2 I would have checked for something like ^jon \+ALL=(ALL) \+ALL$. I set up my work laptop as another test node, and used puppet to install some packages that I commonly use:

class jon-desktop  
  package   ['icedove', 'git-core', 'vim-gnome', 'vinagre', 'build-essential',
             'devscripts', 'subversion', 'git-buildpackage', 'mutt',
             'offlineimap', 'ascii', 'gitk', 'chromium-browser'
            ]: ensure => installed  
 

This worked fine, but is a little verbose and the package list is awkward to maintain buried inside the puppet syntax. I spent some time trying to see whether I could populate a puppet list based on the contents of a file: then I could list the packages one-per-line in a separate file. I haven't found a way of doing that yet. Using my laptop as a second node also exposed some interesting puppet client behaviour. Once I went off-site, the laptop tried to look up puppet on foreign networks (such as my home network). I would have assumed that, once the strong SSL association had been made, the client would try to connect to the FQDN of the server. This probably isn't a serious problem in practice, as we probably won't need to rely on nodes off-site talking to the configuration server, but I hope that the client doesn't trust any host that happens to answer to puppet... I fixed this by hacking my hosts file to include an entry for puppet. I could maintain this hack using Puppet itself, which would protect me against stale definitions if any renumbering takes place. I could also have added a line

server = puppet.fqdn.example.org

in /etc/puppet/puppet.conf, which is a more robust way of solving the problem.

A few weeks ago it became apparent to me that I may end up having to run Windows on my work PC. We're getting new machines soon with Vista images preloaded. There's a Linux image option (of unknown base, but possibly Ubuntu), but I've kinda been assuming that I could continue in my current approach - I run Debian, and accept that IT won't give me any support in doing so other than caring about the hardware. Seems like a reasonable deal to me. Except it requires an infrastructure that's platform agnostic, and that's the problem. There's a danger our new bug tracking system is much, much happier in IE than anything else. That's kinda a problem if I can't access it. The event last week was around a web streamed meeting, which is annoying but not as critical. I was unhappy at this realization. Very unhappy. And yet I had trouble finding the words to explain why. I don't do Linux advocacy these days (I'm not sure I ever really did). I probably gave up at the point my parents' bought a replacement machine for my mother while I was living in England and went for a Windows box (she'd been running Debian) because "they had knowledge of that in the house given I wasn't around". And then promptly rang me after it arrived to ask how to configure networking. Anyway. If I can't come up with some decent reasons about why I run Linux over Windows then I can't justifiably complain if I end up with a Windows desktop. So I think I need to collect together some thoughts about it. I'll try to break them up into a bunch of separate posts rather than one huge dump that no one will read. Let's start with the obvious: Familiarity This was the first question a coworker asked; is it because you're used to Linux? And it would be untruthful to say that doesn't play a part. I've been running Linux on the desktop for the past 12 years or so (well, I had few years running FreeBSD on my primary desktop too, but close enough). The only time I've ended up with a Windows desktop was when I worked for Aviva. I don't currently have a working Windows install anywhere. I have little experience of working with Windows these days. I mean, I can do it, but I don't find it comfortable (to the extent that I managed about 3 hours when I ended up with a Windows desktop back in August before installing Debian on it). That's the argument often used to stay with Windows (as per my parents, above). And it's not accurate. Why did I try Linux in the first place, and stick with it long enough to get to this point?

Hace ya alg n tiempo escrib sobre el uso de libpam-ccreds y libnss-db para conseguir la implementaci n de un servicio de cach de credenciales. Sin embargo, hace casi un a o revisit el producto Likewise Open, en un proyecto grande de autenticaci n de Linux contra un Active Directory de Microsoft, o contra un dominio Windows desarrollado con Samba. En realidad Likewise Open elimina la incertidumbre de un setup artesanal de cach de credenciales, siempre y cuando el equipo se est loggeando contra un dominio Windows. Si usted tiene la necesidad de integrar una distribuci n de Linux moderna (una versi n reciente de Debian, Ubuntu, Fedora, por ejemplo) con un dominio Windows servidor por un Active Directory o por Samba, mi recomendaci n es que use Likewise Open. Likewise es libre, abierto y gratuito, y viene en los repositorios de muchas distribuciones, o se baja de la p gina Web de Likewise. Tiene dos versiones (paquetes), likewise-open-gui y likewise-open; el primero instala el segundo y ofrece una interfaz gr fica sencilla para unir el equipo al dominio. Solo se requiere el nombre del dominio, el nombre del equipo (se toma de hostname) y el usuario y la clave de un usuario que pueda agregar equipos al dominio. Como siempre, la resoluci n del dominio se hace consultando al DNS provisto en la configuraci n de red (u otorgado por el DHCP) por ciertos registros SRV, para obtener la IP de uno de los controladores de dominio, y luego ciertas conexiones a algunos puertos del controlador de dominio. Por lo tanto es importante que, si va a probar este escenario en una m quina virtual, la conexi n est en modo puente con la red en la que se encuentra el controlador de dominio. Una vez que el equipo se une al dominio, se crea la cuenta de m quina en el controlador de dominio, y al cerrar la sesi n, ya pueden ingresar a Linux los usuarios del dominio, usando la sintaxis DOMINIO.AD\usuario o DOMINIO\usuario (formas largas y cortas) y la contrase a del dominio. Las pol ticas de inicio de sesi n y contrase as ser n respetadas. Tambi n se puede usar domainjoin-cli para unirse por CLI. Obviamente, Likewise ya ofrece el servicio de cach de credenciales y de cach de usuarios y grupos (importa los grupos del dominio) y lo hace de forma transparente. Por ello, en muchos casos yo recomendar a que si tienes un OpenLDAP y quieres hacer cach con pam-ccreds y nss-db, haz un upgrade de OpenLDAP a un dominio usando Samba y usa Likewise. Ahorra muchos dolores de cabeza. En Likewise Open no hay soporte para GPOs. En ning n caso funcionar n las GPO que se hacen para Windows, pero en versiones pagadas de Likewise hay una funci n que a ade nuevas GPO para GNOME y otras aplicaciones. No he probado estas funcionalidades.