Search Results: "ag"

28 January 2012

Christian Perrier: 2012 update 7 for Debian Installer localization

Status for D-I level 1 (core D-I files): Status for D-I level 2 (packages that have localized material that may appear during default installs, such as iso-codes, tasksel, etc.): Status for D-I level 3 (packages that have localized material that may appear during non-default installs, such as win32-loader) Full 100% completeness (hall of fame) for 17 languages: Bulgarian, Czech, German, Esperanto, Spanish, Persian, French, Italian, Japanese, Kazakh, Dutch, <polish>, Portuguese, Russian, Slovak, Turkish Simplified Chinese

27 January 2012

Petter Reinholdtsen: Handling non-free firmware in Debian Edu/Squeeze

With some computer hardware, one need non-free firmware blobs. This is the sad fact of todays computers. In the next version of Debian Edu / Skolelinux based on Squeeze, we provide several scripts and modifications to make firmware blobs easier to handle. The common use case I run into is a laptop with a wireless network card requiring non-free firmware to work, but there are other use cases as well. First and foremost, Debian Edu provide ISO images for DVD and CD with all firmware packages in the Debian sections main and non-free included, to ensure debian-installer find and can install all of them during installation. This take care firmware for network devices used by the installer when installing from from local media. But for example multimedia devices are not activated in the installer and are not taken care of by this. For non-network devices, we provide the script /usr/share/debian-edu-config/tools/auto-addfirmware which search through the dmesg output for drivers requesting extra firmware. The firmware file name is looked up in the Contents-ARCH.gz file available in the package repository, and the packages providing the requested firmware file(s) is installed. I have proposed to do something similar in debian-installer (BTS report #655507), to allow PXE installs of Debian to handle firmware installation better. Run the script as root from the command line to fetch and install the needed firmware packages. Debian Edu provide PXE installation of Debian out of the box, and because some machines need firmware to get their network cards working, the installation initrd some times need extra firmware included to be able to install at all. To fill the PXE installation initrd with extra firmware, the /usr/share/debian-edu-config/tools/pxe-addfirmware script is provided. Again, just run it as root on the command line to fill the PXE initrd with firmware packages. Last, some LTSP clients might also need firmware to get their network cards working. For this, /usr/share/debian-edu-config/tools/ltsp-addfirmware is provided to update the LTSP initrd with firmware blobs. It is used the same way as the other firmware related tools. At the moment, we do not run any of these during installation. We do not know if this is acceptable for the local administrator to use non-free software, and it is their choice. We plan to release beta3 this weekend. You might want to give it a try.

Jon Dowland: An Early Start

early start
An early start.

Alexander Reichle-Schmehl: Release Critical Bug report for Week 04

The bug webinterface of the Ultimate Debian Database currently knows about the following release critical bugs:
In Total:1491
Affecting Wheezy:893
Wheezy only:179
Remaining to be fixed in Wheezy:714
Of these 714 bugs, the following tags are set:
Pending in Wheezy:48
Patched in Wheezy:102
Duplicates in Wheezy:45
Can be fixed in a security Update:19
Contrib or non-free in Wheezy:14
Claimed in Wheezy:0
Delayed in Wheezy:5
Otherwise fixed in Wheezy:48
Ignoring all the above (multiple tags possible) 491 bugs need to be fixed by Debian Contributors to get Debian 7.0 Wheezy released. However, with the view of the Release Managers, 788 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.

Michal &#268;iha&#345;: Future of Gammu

All of Gammu and Wammu related projects are slowly dying under my hands in past months (maybe I could even say years). The reason for this is lack of motivation and time to work on that properly. Last year I've managed to collect some bugfixes and to fix some bugs myself what lead to releasing Gammu 1.31.0, which seems to be quite good release. But since then, I've again hardly done any work there and my biggest motivation for working on Gammu is that without my involvement the project would be probably completely dead. This is definitely not the best motivation and the outcome can be clearly seen. The project definitely has it's problems (I could name them, but let's avoid making this blog post too long), but there are quite a lot of users using it. Currently most interesting feature seems to be SMS daemon, which is probably superior to what others provide, because this is where Gammu gets most of it's new users. Unfortunately not much of them are active in development, the biggest contribution I can expect there is to fix issues they face. On the other side bug tracker and mailing list are full of reported bugs. Not speaking of feature requests to support new phone models. Some of them should be easy to support like new S40 based Nokia's, but things like Android, iPhone or Windows Mobile would require much more work. Of course the big question is whether somebody needs anything else than SMSD. In modern phones, you anyway have most of the data on "cloud" as well, being it Google, Apple or Microsoft and possibility of doing backups to the computer are not that important as in past. I'm definitely not using Gammu to backup my phone (anyway MeeGo is not supported) and I don't think I will in near future. Simply there are better and easier ways to get my data out of phone than implementing support for Gammu. Anyway if anybody is willing to help Gammu now or in future, I'm definitely willing to help him.

Filed under: English Gammu 6 comments Flattr this!

Rapha&#235;l Hertzog: People Behind Debian: Josselin Mouette, founder of the Debian GNOME team

Josselin Mouette is one the leaders of the pkg-gnome team, he takes sound technical decisions and doesn t fear writing code to work-around upstream issues. He deserves kudos for the work he has put into packaging GNOME over the years. He can also be very sarcastic (sometimes he even enjoys participating to flamewars on debian lists), and there are quite a few topics where we have long agreed to disagree. But this kind of diversity is also what makes Debian a so interesting place Read on to learn more about the pkg-gnome team, its plans for Wheezy, Josselin s opinion on the GNOME 3 switch, and much more. Raphael: Who are you? Josselin: I am a 31 years old Linux systems engineer. I started in life with physics, which I studied at the ENS Lyon. I started a thesis on experimental and numerical models for optoelectronics, but when it became clear that research was not for me, I abandoned it and accepted a job at the CEA, which holds the largest computing center in Europe. Working on these machines has been the most awesome job ever (except for it being near Paris). After that I worked a bit on system monitoring technologies. I am married, currently living in Lyon, and working for EDF (the French historical electricity company) on scientific workstations using Debian. EDF is using Debian on more than a thousand workstations and holds the fastest Debian supercomputer in the world (200 Tflops), which makes it another obvious place for Debian developers. Raphael: How did you start contributing to Debian? Josselin: I discovered Debian in 1999 while studying at the ENS, which is one of the biggest nests of Debian developers while being a small place, it is producing almost one Debian developer per year on average. After wondering for a while what it could be useful for, hacking on a slink snapshot made me think that it was for, well, everything except for gaming. Later, in 2002, when I was working on optoelectronics computing codes, I started to package them for Debian in order to make them easier to install, for us as well as other labs over the world. I started the NM process, and it was going smoothly but also going to take time. However, at that moment, the frozen-bubble game went out and made quite some buzz. Since I knew a guy who knew the game s developer, he asked me to package it. The package found 3 sponsors in a very short time and was fast-tracked into the archive at a speed that was unseen before. After which the NM process was completed very quickly. At that time, I was a heavy WindowMaker user, but I didn t like the direction the project was taking (actually, I wonder if there was one). GNOME was starting to become attractive, but its packaging in Debian was very ineffective, with many inconsistent packages maintained by people who didn t ever talk to each other some of them didn t speak English, and some of them didn t talk at all. Together with awesome people, among which Jordi Mallach, Gustavo Noronha Silva, JHM Dassen, Ross Burton and S bastien Bacher, we started the GNOME team in 2003, introducing consistent packaging practices, and initiating synchronized uploads. Releasing a completely integrated GNOME 2.8 in sarge was a considerable achievement; proving (together with the Perl team) that a team was the best way to maintain large package sets changed the way people work on Debian.
Proving [ ] that a team was the best way to maintain large package sets changed the way people work on Debian.
Raphael: You re one of the most active contributors of the team which is packaging GNOME for Debian. What would you suggest to a new contributor who would like to help the team? Josselin: There are several ways to contact the team, but the recommended one has always been IRC. We hang on #debian-gnome on the OFTC network, so just come around and ask for us. The real question is what you want to do in the team. Of course, most new volunteers want to help packaging the latest and greatest version of GNOME into unstable as soon as possible, but unless they already have Debian background, this is not the easiest task. Since there are already people working on this, the big packages are usually waiting on dependencies. I used to direct newcomers towards bug triage, but it is a tedious task and I m now convinced that our huge bug backlog will never be dealt with. The most useful thing to do for newcomers now is probably to find a GNOME or GNOME-related package that needs improvement or is lagging behind, and simply try to work on it. You can also come and fix the bugs you find annoying. Find a patch on the GNOME bugzilla, or cook it yourself, propose it, and if it s worthy enough you ll soon get commit access.
Our huge bug backlog will never be dealt with.
At this point I feel worth mentioning that if no one answers in 10 minutes, it doesn t mean that no one will answer in 2 hours, so please stay on the channel after asking. Raphael: There s been some controversy about GNOME 3 and the direction that the project is taking. What s your personal stance on GNOME 3? And what s the position of the pkg-gnome team? Josselin: The controversy is not new to GNOME 3, but the large-scale changes made with it have put it more prominently. The criticism usually boils down to a few categories:
  1. General lack of configurability
  2. Strange design decisions
  3. Red Hat centric development
  4. Hardware requirements
  5. Change resistance
The lack of configuration options has been an ongoing criticism since GNOME 2.0 has decided to rip off most of them. Of course, when the control center was redesigned again for 3.0, there was a surge of horrified exclamations from people who missed their favorite buttons. On this topic, I fully concur with GNOME developers. The configuration option that is useful for you is not necessarily useful for someone else. Of course, sometimes developers go a bit too far, but the general direction is right. At work, we found that only a minority of users actually configure anything on their desktops: they just want something that works to launch their applications. Apple and Google have sold millions of devices by making them the simplest possible and without any configuration. Design decisions are, on the contrary, individual decisions, and each of them, while having reasons behind it, can be questioned. I remember seeing a lot of complaints when the OK and Cancel buttons were reversed in dialog boxes, something that nobody questions anymore. GNOME Shell is full of such changes; some are easy to get accustomed with, some others just make eyebrows raise. The most obvious example is the user menu in GNOME 3.2, which contains an entry to configure your Google account, but no entry to shutdown the computer. Both decisions were taken independently, each of them with (good or bad) reasons, but the result is simply ridiculous. The default configuration in Debian will contain an extension to make it a bit better, but on the whole we don t intend to diverge from the upstream design, on which a lot of good work has been done.
On the whole we don t intend to diverge from the upstream design, on which a lot of good work has been done.
Point 3 is more complex. Red Hat being the company spending the most on GNOME, it is obvious that their employees work on making things work for their distribution. An example is the recurring discussions about relying on system services that are currently only implemented by systemd. Since there is a lot of (mostly unjustified) resistance against systemd in Debian, and since it won t work on kFreeBSD anyway, someone needs to develop an alternative implementation of these services for upstart and sysvinit. Everything is in place for someone else to do the job but it has to be done, and this can be frustrating. Especially since it can also be hard to integrate changes needed for other distributions . Hardware requirements are mostly a consequence of the previous criticism: there s hardware that most distributions just don t want to bother supporting. We ve seen it in squeeze with the introduction of a hard dependency on PulseAudio. The Debian GNOME team (together with the Gentoo maintainers) made this dependency optional, carrying heavy patches, in order to cover the cases where it does not work. Now that it has gained more maturity, making this effort obsolete, the new tendency is to require 3D acceleration. For various reasons, it is not available to everyone . On this matter, the position of the Debian GNOME team has always been to support as much different configurations as possible with reasonable effort. Thanks to efforts from the incredible Vincent Untz, upstream supports a so-called fallback mode , which is the GNOME panel from 2.x with a lot of its bugs fixed. We intend to support this mode for as long as reasonably possible in Debian, possibly even after upstream ends up dropping it. However, other applications are going to require 3D because GStreamer is moving to clutter too, affecting video playback performance on non-accelerated systems . For epiphany this is not a problem; only embedded video will be affected. But for totem, this is a major issue; because of that we will probably keep totem 3.0 in wheezy. Finally, there is a natural human tendency to dislike change (I have it too), and it applies a lot to desktop users habits. Needless to say a change of such a scale as introducing GNOME Shell can trigger reactions. However, I don t think it is reasonable, because of this resistance, to keep gnome-panel 2.x in Debian. This would be a lot of work on obsolete technology, and would prevent the upcoming removal of a lot of deprecated libraries. This time is much better spent improving gnome-panel 3.x in Debian and keeping the fallback mode great. One of the change that was made in Debian was to make it easier to find, being available as GNOME Classic directly from the login manager, instead of having to find it in an obscure configuration panel. In all cases, I would recommend to actually try GNOME Shell for a few hours before ditching it. I had never been accustomed to a new environment as quickly ever before.
In all cases, I would recommend to actually try GNOME Shell for a few hours before ditching it.
Having seen several of my GDM patches reverted without a warning, I know we are not finished with carrying patches in Debian packages.
Scientific workstations are a non-trivial example, since there is a measurable effect of using 3D in the window manager on heavy 3D applications.
On the other hand, on accelerated systems, this feature should end up improving performance a lot. Raphael: What are your plans for Debian Wheezy? Josselin: The first goal of the GNOME team is, of course, to provide again a great desktop environment to work on. For wheezy it will probably be based on GNOME 3.4. There also needs to be some work on package management interfaces. Upstream bases everything on PackageKit, but it is not as featureful as the aptdaemon Ubuntu technology. If I have time, I would also like to improve HTTP proxy support, since currently it is based on a stack of terrible hacks. Raphael: If you could spend all your time on Debian, what would you work on? Josselin: Obviously I would like to make GNOME in Debian even better. That would imply working on underneath dependencies (what we now like to call plumbing) to make sure everything is working great. This would also imply working more as GNOME upstream to make it more suitable for our needs. I would also work on large-scale improvements on the distribution, like conditional recommends which I d love to see implemented , or automatic build-dependency generation. I would also work on the installer to make it better for desktops machines. The idea is to automatically install language packs, or glues between two packages when both packages are installed. Raphael: What s the biggest problem of Debian? Josselin: The obvious answer is the same as the one most people you interviewed before gave: not enough members in core teams. A lot of developers join Debian to work on a small number of pet packages, and don t necessarily want to be involved with existing teams. It is probably still not obvious enough that the primary way to start contributing to Debian is to join an existing team. But if there is one thing that is preventing Debian from gaining more momentum now, it is a completely different one: the too short support timeframe. 3 years is really not enough for corporate users. One year to migrate from one version to another is too short, and it is not possible to skip a release. It is definitely possible to change that with reasonable effort: the long-term support after 3 years doesn t have to cover the same perimeter as the short-term one. For example, we could upgrade the kernel to the version in the current stable release, and stop fixing all non-remote security holes. The important thing is to cover the most basic needs: companies are ready to take the risk of having less support if it allows skipping a version, but not the risk of having no support at all. And even more important is to say that you do something. Red Hat says they support a release for 10 years, but of course after 5 years the supported perimeter is extremely small.
3 years [of support] is really not enough for corporate users.
Long-term support will not magically fix all problems in Debian, but it will bring more corporate users into the picture. And with corporate users come paid Debian developers, who can work on critical pieces of the system. Debian was built on the synergy between individuals and companies, and in recent years perhaps as a reaction against what happened with Ubuntu we ve kind of forgot the latter. A lot of individuals have joined the project, and they are actively working, for example, on shortening the release cycle, which goes against the interest of professionals. We should embrace again such users and developers, and that means adapting to the current needs of larger entities. Raphael: You re the maintainer of python-support, a packaging helper that was competing with python-central. Both helpers are now deprecated in favor of dh_python2. Does this mean that the situation of Python in Debian is now sane? Or are there remaining problems? Josselin: dh_python2 (and the Python3 version, dh_python3) has a sane enough design. It fixes a lot of issues in python-central and also python-support, at the expense of somehow reduced functionality for developers. However, just like the previous tools, it merely works around design mistakes in the Python interpreter. For example it is not possible to split binary modules, pure-Python modules and byte-compiled modules in different directory trees, like Perl does although PEP 3147 introduces a way to do so. There is still no sane and standardized way to deal with module versions. There is no difference made between the module (which is a part of language semantics) and the file containing it (an information which depends on the implementation). Developers heavily rely on introspection features and make assumptions based on the implementation, that make it impossible to work around problems with module files. Such problems are not restricted to Python. Those who fought against Ruby gems could tell even worse stories. While introducing GObject introspection packages in Debian (they can be used in JavaScript and Python to provide modules based on GObject libraries), I was pleased to see a clear distinction between file and module, but I was again struck by the fact you are not forced to declare API versions in your Python/JS code. In all cases, there is no reliable way to detect runtime dependencies in a given Python or JavaScript file, which leaves the maintainer to declare them by hand, and of course, often be wrong about them. Add to that the fact that most errors cannot be detected before runtime. For all these reasons, and while still being fond of Python for scripts and prototyping, I ve become really skeptical of using purely interpreted languages to write real applications. Some GNOME developers are moving away from Python and JavaScript, mostly towards Vala; I can only approve of that move and hope the same happens to other projects. Raphael: Is there someone in Debian that you admire for their contributions? Of course there is the never-sleeping, never-stopping, Michael Biebl who can upload a whole GNOME release in a single week-end. But there are a lot of awesome people who make Debian something that simply works. I could talk about Cyril Brulebois from the X strike force, Julien Cristau from the release team, Sjoerd Simons for his sound advice and work on plumbing, Luca Falavigna who is so fast at processing NEW, to quote only a few of those I work with frequently. And of course, Jordi and Sam for their humor.
Thank you to Josselin for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Note that you can find older interviews on http://wiki.debian.org/PeopleBehindDebian.

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Nikita Youshchenko: Cryptkeeper

Situation: a home Debian-based desktop, used by non-technical family members, without any lock-screen passwords or so to maximize convenience. Need: without making much noise, hide private files from too curious relatives. Solution: aptitude install cryptkeeper.

Craig Small: Unlucky sometimes

Sometimes life throws little curves at you to see if you are still awake, today has been one of those days. fglrx is (apparently) fixed I ve had a long-running problem with fglrx on my laptop. The problem stems from ATI closed-source drivers with one of those laptops that has an ATI and Intel driver. It means I am basically using the slow Intel chip only. This morning I had enough and backed up my home and started to rebuild the laptop with debian 6.0.3. So I kicked off the very very slow process of reformatting the crypto drive (it has taken 5 hours and still going) let it gurgle on its merry way and started to read my email. One of the emails was that my bug about fglrx not working is closed, apparently it is fixed. If I had read that 10 minutes earlier, a simple apt-get install fglrx-driver would of perhaps fixed it; oh well. My problem is now is do I move to the latest driver and hope their fix is my fix or leave it with some ancient version? My preference is the former; I only hope it works! psmisc 22.15 and buffer overflows psmisc has a program called pstree which prints the set of processes in a tree fashion. It hasn t changed much for quite a while. I released version 22.15 and the Debian package 22.15-1. 22.15-1 I also adopted the harden CFLAGS as suggested for procps. I was a little surprised that I received an important bug. The report was saying I had a buffer overflow introduced in 22.15-1, but no relevant code had changed. The compiler options had done their job and stopped a buffer being overflowed. But where exactly was the overflow? Running gdb on pstree quickly showed that it was line 267 of pstree.c which uses strcpy(). That function set off warning bells. The relevant code is:
    PROC *new;
 
    if (!(new = malloc(sizeof(PROC))))  
        perror("malloc");
        exit(1);
     
    strcpy(new-&gt;comm, comm);
Now comm is the short command name you find in /proc//stat. It is fixed in the kernel at 16 characters. The PROC structure has this field as 17 characters long, one extra for the NUL. I went and checked the Linux source and yes, it is still 16 characters long. The clue was in the name of the program that it died on.
#6  new_proc (comm=0x6111b0 " console-kit-dae ", pid=1571, uid=0)
  at pstree.c:267
That string is 17 characters long. The problem is that 16 characters is for the name only. If the name is in brackets or braces, then that 16 character limit doesn t apply. The buffer overflow bug has been there for a long time, but only with the compiler flags did it become visible. Given you need to read names out of the /proc filesystem and if someone can fiddle with that you have bigger problems it doesn t seem to be too much of an issue. It should be (and is in Debian 22.15-2) fixed but is a nice example of the compiler catching bad things.

Lior Kaplan: PHP 5.4 @ Zend

As a Linux integration guy at Zend, most of my time is spent in compiling PHP related code or dealing with the variety of Linux distributions we support. With the coming release for PHP 5.4, we (at Zend) had some interesting stuff going on. As part of the RC phase, I got to check the status of the 50-60 PHP extensions we provide, especially the PECL extensions which have different release cycles than the main PHP. With minor versions, this usually doesn t really matter, but for major versions this means that some extensions need a little bit of love and fixes to work well with the new PHP version. This of course with the help of our developers. The changes are usually one-liners due to a variable type change, or finding commits in the extension s SCM and applying/back-porting it to the current versions (e.g. pecl memcache). Our policy regarding the patches we have, is that they should at least be sent to upstream (a core member or a bug report, e.g. #55703). I think I m in the best position to enforce that patch policy, so in a few recent cases, I found myself asking one of our developers if the patch he sent me was already accepted upstream before willing to take it into the build process (in this case they are used temporarily, till we ll work with the next RC or final release).
While most people build PHP as a final and standalone product, we also test it against ZendServer (or the other way around, depends on your POV). This helps to discover problems related to and implications of the changes done in the major version. During the PHP 5.4 RC cycle (which is still not finished), we had, more than a few times, that an internal problem discovered led to debugging, code reviewing and sending feedback (and patches when relevant) to the PHP project. Providing fixes for the issues found, helps having PHP in a better shape for release. At least for me, that s one of the fun parts of work getting the chance to contribute back to the community (or at least making sure others do, as I don t write the patches myself).

Filed under: PHP

26 January 2012

Guido G nther: git-buildpackage in experimental

I've started uploading snapshots of git-buildpackage to experimental recently. Here's a short list of what changed over the version in wheezy and sid: This blog is flattr enabled.

Ond&#345;ej &#268;ert&iacute;k: When double precision is not enough

I was doing some finite element (FE) calculation and I needed the sum of the lowest 7 eigenvalues of a symmetric matrix (that comes from the FE assembly) to converge to at least 1e-8 accuracy (so that I can check calculation done by some other solver of mine, that calculates the same but doesn't use FE). In reality I wanted the rounded value to 8 decimal digits to be correct, so I really needed 1e-9 accuracy (but it's ok if it is let's say 2e-9, but not ok if it is 9e-9). With my FE solver, I couldn't get it to converge more than to roughly 5e-7 no matter how hard I tried. Now what?

When doing the convergence, I take a good mesh and keep increasing "p" (the polynomial order) until it converges. For my particular problem, it is fully converged for about p=25 (the solver supports the order up to 64). Increasing "p" further will not increase the accuracy anymore, and the accuracy stays at the level 5e-7 for the sum of the lowest 7 eigenvalues. For optimal meshes, it converges at p=25, for not optimal meshes, it converges for higher "p", but in all cases, it doesn't get below 5e-7.

I know from experience, that for simpler problems, the FE solver can easily converge to 1e-10 or more using double precision. So I know it is doable, now the question is what the problem is: there
are a few possible reasons:

When using the same solver for simpler potential, it converged nicely to 1e-10. So this suggests there is no bug in the assembly or solver itself. It is possible that the quadrature is not accurate enough, but again, if it converges for simple problem, it's probably not it. So it seems it is the ill conditioned matrix, that causes this. So I printed the residuals (that I simply calculated in Fortran using the matrix and the eigenvectors returned by LAPACK), and it only showed 1e-9. For simpler problems, it can go to 1e-14 easily. So that must be it. How do we fix it?

Obviously by making the matrix less ill conditioned, which is caused by the mesh for the problem (the ratio of the longest/shortest elements is 1e9) but for my problem I really needed such a mesh. So the other option is to increase the real number accuracy.

In Fortran all real variables are defined as real(dp), where dp is an integer defined at a single place in the project. There are several ways to define it, but it's value is 8 for gfortran and it means double precision.So I increased it to 16 (quadruple precision), recompiled. Now the whole program calculates in quadruple precision (more than 30 significant digits). I had to recompile LAPACK using the "-fdefault-real-8" gfortran option, that promotes all double precision numbers to quadruple precision, and I used the "d" versions (double precision, now promoted to quadruple) of LAPACK routines.

I rerun the calculation ---- and suddenly LAPACK residuals are around 1e-13, and the solver converges to 1e-10 easily (for the sum of the lowest 7 eigenvalues). Problem solved.

Turning my Fortran program to quadruple precision is as easy as changing one variable and recompiling. Turning LAPACK to quadruple precision is easy with a single gfortran flag (LAPACK uses the old f77 syntax for double precision, if it used real(dp), then I would simply change it as for my program). The whole calculation got at least 10x slower with quadruple. The reason is that gfortran runtime uses the libquadmath library, that simulates quadruple precision (as current CPUs only support double precision natively).

I actually discovered a few bugs in my program (typically some constants in older code didn't use the "dp" syntax, but had the double precision hardwired). Fortran warns about all such cases, when the real variables have incompatible precision.

It is amazing how easy it is to work with different precision in Fortran (literally just one change and recompile). How could this be done with C++? This wikipedia page suggests, that "long double" is only 80bit in most cases (quadruple is 128bit), but gcc offers __float128, so it seems I would have to manually change all "double" to "__float128" in the whole C++ program (this could be done with a single "sed" command).

Ben Hutchings: Testing backport of the isci driver for Intel C600 SAS/SATA controllers

Phil Kern made a general call for testing of Debian 6.0.4. I would like to more specifically point out that I backported the isci driver for Intel C600 SAS/SATA controllers. Unfortunately I have not yet had any testing results for this. If you have any machines with this hardware not yet in production, please do consider testing the new Linux kernel package, version 2.6.32-41. Updated: I now have a positive test result from the user who requested this driver in the installer.

Michal &#268;iha&#345;: Dictionaries for N9/N950

I was just about to start writing own viewer for StarDict dictionaries for Harmattan, when I noticed that somebody already took the effort and the application is available. It's called DictionaryStar and it's developed on gitorious. With the hard part done, I've adjusted packaging of various dictionaries I've made available for StarDict so that it works fine on Harmattan. For now only English-Czech one is completed, you hopefully be able to get it soon at Nokia store. The reason I've started with only one is that this pretty much does not fit into content guidelines for Nokia store and I expect problems when this will be passing their QA. So I've decided to push only one for now and once I get it through, adding others will be easy.

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Aigars Mahinovs: Zombies. Wait, don t run away, yet

I never got the craze for the zombie this and zombie that. I saw the premise as thinner than vampire storyline which in my book only had a good day with Buffy franchise. But then I got Kindle and run out of stuff to read and decided to pick up something less lively and more shambling. And you know what I found there are a few great books hiding behind the zombie label. I read them in the worng order, so to help you guys out, here is the way I would recommend to check out if the zombie genre is interesting to you: Start with World War Z: An Oral History of the Zombie War. It is written as a historical book documenting the memories of people that have survived the world wide zombie apocalipse is a series of escalating short stories. This is a perfect bathroom or bus reading. Each story focuses on how people react (or fail to react) to a radical change in their environment. Zombies are a tool to expose the human condition for this book. The next you could read (or you could even skip this if it get a bit boring for you) is The Zombie Survival Guide: Complete Protection from the Living Dead this is a problem solving book, it basically takes a problem ( ZOMBIES! ) a goal ( I want to survive! ) and describes the logical steps needed to reach the goal in the context of the problem. It is very educational on the issue of problem solving, especially with unusual problems. But it can get boring for people if so, don t give up, but just skip this book for now and move on the the best of them all The third is a trilogy, two books are already published, the third is coming soon first books is Feed (Newsflesh, Book 1) and the second is Deadline (Newsflesh, Book 2). This is a rare gem of modern literature. Basically this is a book set in the world long time after a zombie outbreak (with a good reason why and how it happened) where people have already lived a few decades with the problema and the kids are very used to it. So the book is written from a perspective of a young woman and her brother, who were born after Rising and are now into one of the most dangerous profession journalism. :) Early on they become the first bloggers to be picked to follow a presidential election campagn (book was written before Obama campaign really took off) and it only get wilder from there. I really liked these books. So much so, that I will now explore the other zombie fiction books to see if there possibly is something good there as well. Any recommendations?

Ian Wienand: pylint and hiding of attributes

I recently came across the pylint error:
E:  3,4:Foo.foo: An attribute affected in foo line 12 hide this method
in code that boiled down to essentially:
class Foo:
    def foo(self):
        return True
    def foo_override(self):
        return False
    def __init__(self, override=False):
        if override:
            self.foo = self.foo_override
Unfortunately that message isn't particularly helpful in figuring out what's going on. I still can't claim to be 100% sure what the message is intended to convey, but I can construct something that maybe it's talking about. Consider the following using the above class
foo = Foo()
moo = Foo(override=True)
print "expect True  : %s" % foo.foo()
print "expect False : %s" % moo.foo()
print "expect True  : %s" % Foo.foo(foo)
print "expect False : %s" % Foo.foo(moo)
which gives output of:
$ python ./foo.py 
expect True  : True
expect False : False
expect True  : True
expect False : True
Now, if you read just about any Python tutorial, it will say something along the lines of:
... the special thing about methods is that the object is passed as the first argument of the function. In our example, the call x.f() is exactly equivalent to MyClass.f(x). In general, calling a method with a list of n arguments is equivalent to calling the corresponding function with an argument list that is created by inserting the method s object before the first argument. [Official Python Tutorial]
The official tutorial above is careful to say in general; others often don't. The important point to remember is how python internally resolves attribute references as described by the data model. The moo.foo() call is really moo.__dict__["foo"](moo); examining the __dict__ for the moo object we can see that foo has been re-assigned:
>>> print moo.__dict__
 'foo': <bound method Foo.foo_override of <__main__.Foo instance at 0xb72838ac>> 
Our Foo.foo(moo) call is really Foo.__dict__["foo"](moo) -- the fact that we reassigned foo in moo is never noticed. If we were to do something like Foo.foo = Foo.foo_override we would modify the class __dict__, but that doesn't give us the original semantics. So I postulate that the main point of this warning is to suggest to you that you're creating an instance that now behaves differently to its class. Because the symmetry of calling an instance and calling a class is well understood you might end up getting some strange behaviour, especially if you start with heavy-duty introspection of classes. Thinking about various hacks and ways to re-write this construct is kind of interesting. I think I might have found a hook for a decent interview question :)

Russ Allbery: Do symbols files make sense for C++?

I also posted this to debian-devel, which is where the discussion will be, but I wanted to post it on my journal as well so that others who may be interested will see it on Planet Debian. For those not familiar with Debian, this concerns the implications of a new feature for how Debian tracks shared library dependencies. I'm currently working on the Policy modification to document (and recommend) use of symbols instead of shlibs, but I'd only personally used symbols with C libraries. Today I decided that I should try adding a symbols file to a C++ library, particularly if I'm going to recommend everyone do it. I tried this exercise with xml-security-c, which is, I think, a reasonably typical C++ library. Not the sort of core C++ library that would sit at the center of the distribution, but a random software package that's in Debian because other things use it. The experience was rather interesting, and I ended up uploading the new version without a symbols file and continuing to just use shlibs. That's for the following reasons:
  1. The generated symbols file was HUGE. Hundreds of lines. This is a marked difference from the typical C symbols file, which is of quite manageable size. Some of that is that the library provides a lot of different classes, but some of it is that C++ just generates a lot of exported symbols. There's no way that I could do what I would do with a C library and understand those symbols, why they're there, and whether they are likely to have changed between revisions.
  2. Generating a reasonable symbols file was a pain. Generating an unreasonable symbols file that just contains all of the mangled symbols is largely mechanical and uninteresting, but that symbols file doesn't seem to me to convey useful information. So I did some scripting to translate the symbols back with c++filt, and add (c++) tags, and then try to understand what I was looking at and figure out whether I should sort the symbols list because the default sort is by mangled name, which is meaningless. This is a rather unappealing process. It's not particularly difficult, but it's very awkward and feels like it's missing vital tools.
  3. The resulting symbols file is incomprehensible to someone without strong knowledge of C++. It's full of opaque entries that don't make sense to the non-C++ programmer, which I suspect is a substantial number of people who package C++ libraries for Debian. I know enough C++ from school that I can evaluate security fixes, make simple patches, and review upstream changes, and I think that's all that should be needed to package things for Debian. But I'm deeply uncomfortable producing a symbols file on my own that contains entries for things that I know nothing about and cannot evaluate when they've last changed, like "non-virtual thunk to FooClass::~FooClass@Base".
  4. Once I had a symbols file that resulted in a successful build and that I could have uploaded, I started thinking about how I was going to maintain it. With a C program, I would change the symbols file versions when the underlying function implementation changes in a way that may not offer eqiuvalence, similar to bumping shlibs. I realized that I was going to have no idea when that happened, and the only way that I would maintain the symbols file would be to either trust upstream to maintain ABI equivalence and therefore only change the symbols file when upstream changes the SONAME, or not trust upstream to maintain ABI equivalence and therefore change all the versions with each new upstream release. That gives me exactly the same semantics as a shlibs file, so what's the point in having a symbols file?
  5. The exported symbols of the library contained many symbols that obviously weren't really from that library, but instead were artifacts of the C++ compilation process, things like instantiations of std::vector. Do those go into the symbols file? Do they change from architecture to architecture? If they disappear again, is that actually an ABI break? How do I know? It's all very mysterious, and while shlibs provides the same semantics as just ignoring this, at least I'm not then including in the package data, generated by me, things that I'm just blindly ignoring.
I came away from this experience thinking that I should revise the Policy amendment to say that symbols files are really for C libraries and for C++ libraries with either a tightly maintained symbol export list or maintained by a C++ expert, and that most C++ library maintainers should just not bother with this and use shlibs, bumping the shlibs version or not based on their impression of how good upstream is at maintaining ABI equivalence. But that feels like a result contrary to what I had previously thought was the intended direction, so I wanted to ask the Debian development community as a whole: am I missing something? Are these symbols files actually useful? Am I missing some trick to make them useful?

MJ Ray: Phones, Privacy and Co-ops

And now a slightly longer than usual rant: The problem with the o2 network disclosing mobile browsers phone numbers that I repeated 2 days ago (and it appeared on our co-op website) snowballed yesterday to the point that it was on the short bulletins from ITN, BBC, IRN and probably many more. And then o2 fixed it. Good! The reply claims that it s only since 10th January which is rather at odds with other claims that it has been happening since at least March 2010 in some situations. I started buying from o2 in December. I was using Three, but their network where I stay in Norfolk isn t reliable and you can t just buy a device in a shop for The Phone Co-op. The dongle from o2 is a recent Huawei USB device that just worked in debian and was fairly easy for me to get working in Ubuntu. There s space in it for a memory card, so maybe I could boot from it but that s an idea for later. The o2 deal is OK but not great, and the included wifi is nowhere near as good as it looked: when it says it includes BT Openzone that doesn t include any of the BT Openzone-H hotspots that are much more common. You re only allowed to register one device for wifi, so no using your phone, tablet and laptop at different times! I can t believe it s legal to advertise that as unlimited wifi , but o2 is still a better offer than access to BT Openzone-H hotspots at 39/month (yes, that s the price for wifi-only ). Ultimately, I think the problem is that there s a rubbish choice of mobile (wifi or 3G) internet access providers in the UK. It s a completely and utterly failed market, so you need to use Virtual Private Networks and similar tricks to protect yourself from the dysfunctional networks. My VPN meant my mobile number was safe: how about yours? As luck would have it, I had already proposed a resolution about protecting customer privacy to The Phone Co-op (affiliate link) for our AGM on Saturday 4 February (if you re a member, let me know). We were trying to find a compromise wording and I don t think this little o2 scandal has hurt my proposal at all! At least the phone co-op s mobile service is based on Orange s network, which wasn t affected. How does your network perform? There s an Internet Service Provider evilness test which might tell you.

Joey Hess: announcing github-backup

Partly as a followup to a Github survey, and partly because I had a free evening and the need to write more haskell code, any haskell code, I present to you, github-backup. github-backup is a simple tool you run in a git repository you cloned from Github. It backs up everything Github knows about the repository, including other forks, issues, comments, milestones, pull requests, and watchers. This is all stored in the repository, as regular files, on a "github" branch. Available in Cabal now, in Debian maybe if someone packages haskell-github.

Russell Coker: Links January 2012

Cops in Tennessee routinely steal cash from citizens [1]. They are ordered to do so and in some cases their salary is paid from the cash that they take. So they have a good reason to imagine that any large sum of money is drug money and take it. David Frum wrote an insightful article for NY Mag about the problems with the US Republican Party [2]. TreeHugger.com has an interesting article about eco-friendly features on some modern cruise ships [3]. Dan Walsh describes how to get the RSA SecureID PAM module working on a SE Linux system [4]. It s interesting that RSA was telling everyone to turn off SE Linux and shipping a program that was falsely marked as needing an executable stack and which uses netstat instead of /dev/urandom for entropy. Really the only way RSA could do worse could be to fall victim to an Advanced Persistent Attack :-# The Long Now has an interesting summary of a presentation about archive.org [5]. I never realised the range of things that archive.org stores, I will have to explore that if I find some spare time! Jonah Lehrer wrote a detailed and informative article about the way that American high school students receive head injuries playing football[6]. He suggests that it might eventually be the end of the game as we know it. Fran ois Marier wrote an informative article about optimising PNG files [7], optipng is apparently the best option at the moment but it doesn t do everything you might want. Helen Keeble wrote an interesting review of Twilight [8]. The most noteworthy thing about it IMHO is that she tries to understand teenage girls who like the books and movies. Trying to understand young people is quite rare. Jon Masters wrote a critique of the concept of citizen journalism and described how he has two subscriptions to the NYT as a way of donating to support quality journalism [9]. The only comment on his post indicates a desire for biased news (such as Fox) which shows the reason why most US media is failing at journalism. Luis von Ahn gave an interesting TED talk about crowd-sourced translation [10]. He starts by describing CAPTCHAs and the way that his company ReCAPTCHA provides the CAPTCHA service while also using people s time to digitise books. Then he describes his online translation service and language education system DuoLingo which allows people to learn a second language for free while translating text between languages [11]. One of the benefits of this is that people don t have to pay to learn a new language and thus poor people can learn other languages great for people in developing countries that want to learn first-world languages! DuoLingo is in a beta phase at the moment but they are taking some volunteers. Cory Doctorow wrote an insightful article for the Publishers Weekly titles Copyrights vs Human Rights [12] which is primarily about SOPA. Naomi Wolf wrote an insightful article for The Guardian about the Occupy movement, among other things the highest levels of the US government are using the DHS as part of the crackdown [13]. Naomi s claim is that the right-wing and government attacks on the Occupy movement are due to the fact that they want to reform the political process and prevent corruption. John Bohannon gave an interesting and entertaining TED talk about using dance as part of a presentation [14]. He gave an example of using dancerts to illustrate some concepts related to physics and then spoke about the waste of PowerPoint. Joe Sabia gave an amusing and inspiring TED talk about the technology of storytelling [15]. He gave the presentation with live actions on his iPad to match his words, a difficult task to perform successfully. Thomas Koch wrote an informative post about some of the issues related to binary distribution of software [16]. I think the problem is evenm worse than Thomas describes. Related posts:
  1. Links January 2011 Halla Tomasdottir gave an interesting TED talk about her financial...
  2. Links January 2010 Magnus Larsson gave an interesting TED talk about using bacteria...
  3. Links January 2009 Jennifer 8 Lee gave an interesting TED talk about the...

25 January 2012

Phil Hands: The future arrived

... a week ago, in the shape of Alexandra Daphne Scholz, my enchanting daughter. A proud father shows the world his adorable 6 day old daughter She seems to have inherited my hairstyle. Gundemarie Scholz (my wife) and she are both doing remarkably well, to the extent that they both keep surprising medical staff with their rapid progress. For those of you that care about such things: She was 2.9kg (6lb 6oz) at birth, and 49cm (1'7") tall ... or should that be "long", given that she's not doing so much standing up as yet? What she is doing is sleeping, breast feeding, and excreting ... rather a lot. Between times, it's mostly gurgling cheerfully, looking around at the world, and attempting to study her own hands -- I find her completely fascinating. That being the case, don't expect anything very sensible out of me for the foreseeable future (so no change there, eh? ;-) ) and because I cannot resist the urge, here are a few more snaps of her: Alexandra in the Neonatal unit, having a well earned nap when a day old Alexandra in the Neonatal unit, looking around at the world Alexandra snuggled up in bed this morning As you can see, at only one day old, it seems that she'd already managed to get hold of the Amulet of Yendor, and was having a well earned nap ;-)

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