$ sudo apt-get install packaging-dev

Quilt manages a series of patches by keeping track of the changes each of them makes. They are logically organized as a stack, and you can apply, un-apply, update them easily by traveling into the stack (push/pop). Quilt is good for managing additional patches applied to a package received as a tarball or maintained in another version control system. The stacked organization is proven to be efficient for the management of very large patch sets (more than hundred patches). As matter of fact, it was designed by and for Linux kernel hackers (Andrew Morton, from the -mm branch, is the original author), and its main use by the current upstream maintainer is to manage the (hundreds of) patches against the kernel made for the SUSE distribution.

$ ls debian/patches/
01_use_stdlib_htmlparser_when_possible.diff
02_disable-sources-in-sphinxdoc.diff
03_manpage.diff
06_use_debian_geoip_database_as_default.diff
series
$ cat debian/patches/series
01_use_stdlib_htmlparser_when_possible.diff
02_disable-sources-in-sphinxdoc.diff
03_manpage.diff
06_use_debian_geoip_database_as_default.diff

for where in ./ ../ ../../ ../../../ ../../../../ ../../../../../; do
    if [ -e $ where debian/rules -a -d $ where debian/patches ]; then
        export QUILT_PATCHES=debian/patches
        break
    fi
done

QUILT_PUSH_ARGS="--color=auto"
QUILT_DIFF_ARGS="--no-timestamps --no-index -p ab --color=auto"
QUILT_REFRESH_ARGS="--no-timestamps --no-index -p ab"
QUILT_DIFF_OPTS='-p'

$ quilt series
02_disable-sources-in-sphinxdoc.diff
03_manpage.diff
06_use_debian_geoip_database_as_default.diff
$ quilt applied
No patches applied
$ quilt next
02_disable-sources-in-sphinxdoc.diff
$ quilt push
Applying patch 02_disable-sources-in-sphinxdoc.diff
patching file docs/conf.py
Now at patch 02_disable-sources-in-sphinxdoc.diff
$ quilt push
Applying patch 03_manpage.diff
patching file docs/man/django-admin.1
Now at patch 03_manpage.diff
$ quilt applied
02_disable-sources-in-sphinxdoc.diff
03_manpage.diff
$ quilt unapplied
06_use_debian_geoip_database_as_default.diff
$ quilt pop -a
Removing patch 03_manpage.diff
Restoring docs/man/django-admin.1
Removing patch 02_disable-sources-in-sphinxdoc.diff
Restoring docs/conf.py
No patches applied
$ quilt push 03_manpage.diff
Applying patch 02_disable-sources-in-sphinxdoc.diff
patching file docs/conf.py
Applying patch 03_manpage.diff
patching file docs/man/django-admin.1
Now at patch 03_manpage.diff
$ quilt top
03_manpage.diff

$ quilt push
[...]
Hunk #1 succeeded at 1362 (offset 11 lines).
Hunk #2 succeeded at 1533 with fuzz 1 (offset 4 lines).
[...]

$ quilt pop -a
[...]
$ while quilt push; do quilt refresh; done

$ quilt push
Applying patch 04_hyphen-manpage.diff
patching file docs/man/django-admin.1
Hunk #1 FAILED at 194.
1 out of 1 hunk FAILED -- rejects in file docs/man/django-admin.1
Patch 04_hyphen-manpage.diff can be reverse-applied

$ quilt delete -r 04_hyphen-manpage.diff
Removed patch 04_hyphen-manpage.diff

$ quilt push
Applying patch 01_disable_broken_test.diff
patching file tests/regressiontests/test_utils/tests.py
Hunk #1 FAILED at 422.
1 out of 1 hunk FAILED -- rejects in file tests/regressiontests/test_utils/tests.py
Patch 01_disable_broken_test.diff does not apply (enforce with -f)

$ quilt push -f
Applying patch 01_disable_broken_test.diff
patching file tests/regressiontests/test_utils/tests.py
Hunk #1 FAILED at 422.
1 out of 1 hunk FAILED -- saving rejects to file tests/regressiontests/test_utils/tests.py.rej
Applied patch 01_disable_broken_test.diff (forced; needs refresh)
$ vim tests/regressiontests/test_utils/tests.py    
$ quilt refresh
Refreshed patch 01_disable_broken_test.diff

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• Get a great vantage point. In my case that was my apartment balcony. I actually chose this particular place specifically because of the great views in two different directions from the large windows. But really any high point with a roof will do
• Setup you camera on a tripod in the general direction of the incoming storm, frame the shot to include some ground in the shot, so you get the sense of scale and perspective
• Get a focus lock on either the horizon or some far away building an then switch to manual focus to preserve that. You want the lens focused to infinity as the action will be outside the normal focus range of most lenses
• Set manual mode, 5-10 second exposure, aperture (F) to 8 or above, no flash, iso 100
• Take a test shot, make sure you bracketing is ok, make sure that the sky is dark or black without the lightning, but that if there are any lights from buildings that those are bright and clear and sharp
• I use 5 second exposures. If you set it longer, you will get less shots to check and more chance of more than one lightning per shot, but you will then have to up the aperture to avoid overexposure and you do not want aperture over F16, because then you will loose detail due to diffraction in the lens. If it is too dark, either increase exposure time, or up the iso to 200, but do not lower F under 8, otherwise you risk out of focus shots.
• Disable long exposure noise reduction this feature works by taking another photo with the shutter closed, that will take extra time the same length as your exposure time, which means that you will miss half the lightning strikes
• Find some way to make the camera shoot continually without your action. I switched my camera to continuous shot mode and then used a bit of duck tape, a couple zip ties and a plastic nob to press the shutter button and keep it pressed down fully all the time. This makes the camera take a new shot as soon as it is done with the last one, so with a 5 second exposure it takes a photo every 5 seconds.
• Make sure you have plenty of space on the card and a full battery. I had a 32Gb SD card, but I barely shot 8Gb in one stormy evening
• Watch the show! Do not forget to adjust the way the camera is pointing as the storm moves. There is a splitsecond window where the camera viewfinder shows the image between the shots, you can use that to make sure that the shot is looking good after adjusting the camera location.
• After all is done, just filter out the pictures with some lightning in them It is usually easy to see even in a thumbnail

• [1] http://cuddletech.com/blog/pivot/entry.php?id=984
• [1] http://etbe.coker.com.au/2012/03/23/cheap-nas-devices-suck/

1. New Storage Developments Eweek has an article on a new 1TB Seagate drive....
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• using Build-Depends-Indep
• stage building
• cross compilation

Build-Depends: huge (>= 1.0) [i386 arm] <!embedded !bootstrap>, tiny

I'm really sorry to inform you that my supervisor refused the share transfer request to the other account. He told me that we do not transfer products either in those cases. I deeply apologize since I thought it was possible. I thank you for your confidence in Gandi, and hope that this occurrence does not deter you from continuing with us.

$ mkdir build
$ gunzip -c config.gz > build/.config # Or whatever you need to prepare a .config
$ make silentoldconfig prepare headers_install scripts ARCH=arm CROSS_COMPILE=arm-eabi- O=build KERNELRELEASE= adb shell uname -r 

#include <linux/module.h>       /* Needed by all modules */
#include <linux/kernel.h>       /* Needed for KERN_INFO */
#include <linux/init.h>         /* Needed for the macros */
static int __init hello_start(void)
 
  printk(KERN_INFO "Hello world\n");
  return 0;
 
static void __exit hello_end(void)
 
  printk(KERN_INFO "Goodbye world\n");
 
module_init(hello_start);
module_exit(hello_end);

obj-m = hello.o

MODULE_INFO(vermagic, VERMAGIC_STRING);

hello: version magic '3.0.21-perf-ge728813-00399-gd5fa0c9' should be '3.0.8-perf'

struct module __this_module
__attribute__((section(".gnu.linkonce.this_module"))) =  
 .name = KBUILD_MODNAME,
 .init = init_module,
#ifdef CONFIG_MODULE_UNLOAD
 .exit = cleanup_module,
#endif
 .arch = MODULE_ARCH_INIT,
 ;

struct module
 
        (...)
#ifdef CONFIG_UNUSED_SYMBOLS
        (...)
#endif
        (...)
        /* Startup function. */
        int (*init)(void);
        (...)
#ifdef CONFIG_GENERIC_BUG
        (...)
#endif
#ifdef CONFIG_KALLSYMS
        (...)
#endif
        (...)
(... plenty more ifdefs ...)
#ifdef CONFIG_MODULE_UNLOAD
        (...)
        /* Destruction function. */
        void (*exit)(void);
        (...)
#endif
        (...)
 

static const struct modversion_info ____versions[]
__used
__attribute__((section("__versions"))) =  
	  0xsomehex, "module_layout"  ,
	  0xsomehex, "__aeabi_unwind_cpp_pr0"  ,
	  0xsomehex, "printk"  ,
 ;

hello: disagrees about version of symbol symbol_name

bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
                                    struct module *owner,
                                    void *data),
                         void *data)
 
        struct module *mod;
        static const struct symsearch arr[] =  
                  __start___ksymtab, __stop___ksymtab, __start___kcrctab,
                  NOT_GPL_ONLY, false  ,
                  __start___ksymtab_gpl, __stop___ksymtab_gpl,
                  __start___kcrctab_gpl,
                  GPL_ONLY, false  ,
                  __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
                  __start___kcrctab_gpl_future,
                  WILL_BE_GPL_ONLY, false  ,
#ifdef CONFIG_UNUSED_SYMBOLS
                  __start___ksymtab_unused, __stop___ksymtab_unused,
                  __start___kcrctab_unused,
                  NOT_GPL_ONLY, true  ,
                  __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
                  __start___kcrctab_unused_gpl,
                  GPL_ONLY, true  ,
#endif
         ;
        if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
                return true;
        (...)

struct symsearch  
        const struct kernel_symbol *start, *stop;
        const unsigned long *crcs;
        enum  
                NOT_GPL_ONLY,
                GPL_ONLY,
                WILL_BE_GPL_ONLY,
          licence;
        bool unused;
 ;

$ adb shell dmesg   grep "\.init"
<5>[01-01 00:00:00.000] [0: swapper]      .init : 0xc0008000 - 0xc0037000   ( 188 kB)

$ python extract-symvers.py -B 0xc0008000 kernel-filename > Module.symvers

$ cp /path/to/Module.symvers build/
$ make M=/path/to/module/source ARCH=arm CROSS_COMPILE=arm-eabi- O=build modules

$ adb shell
# insmod hello.ko
# dmesg   grep insmod
<6>[mm-dd hh:mm:ss.xxx] [id: insmod]Hello world
# lsmod
hello 586 0 - Live 0xbf008000 (P)
# rmmod hello
# dmesg   grep rmmod
<6>[mm-dd hh:mm:ss.xxx] [id: rmmod]Goodbye world

• I've wrapped up a couple of years of discussions with FSF representatives, proposing a joint working group on FSF' assessment of Debian Free-ness. Some news coverage ensued. The discussion list that has been set up welcomes participants and, in particular, could use some more DDs, fond of Debian principles but also interested in external review of our free/non-free separation.
• DebConf12 has happened!, and many of us attended it. Due to family reasons I've been able to attend only DebCamp and DebConf day-0, just in time to deliver the traditional "bits from the DPL" speech. Among other topics, in the speech I've discussed governance scaling issues in our governance, and in particular about the role of the DPL --- issue which I'm partly trying to address with the "DPL helpers" initiatives. Slides and videos of the talk are available. As many others DebConf people, I took part in Nicaraguan TV shows about DebConf, showing a good deal of interest by the local media in our presence. I don't have links to the recordings yet, but I suspect DebConf orga people will provide them as soon as they're available.
• Many others DebConf12 events are relevant for future Project directions. I went through many of the events I've missed thanks to the work of the video team and of the gobby note takers. I recommend doing the same. Some events are particularly relevant to recent project-wide discussions, such as EFI, hijacking, and the release process and I'm sure you'll find more If you're a DebConf12 speaker and produced slides, please upload them to penta, so that they could be used as future reference.

• On the hardware front, we bought another server according to DSA's "5-year plan". It will be used as a ganeti node at the man-da hosting location. We bought it thanks to donated money, for a total of ~6'600 EUR.
• (After ~8 months of pestering,) we got from SPI a data dump of Debian financial transactions there. Thanks for this result goes to the SPI Board and in particular to Robert Brockway and Joerg Jaspert. This was the last blocker to produce detailed financial reports for the past couple of years of Debian activities. Unfortunately, it still is a blocker: Debian auditors found out that the data dump is not complete. SPI will send us remaining data soon , but I don't have an ETA, unfortunately.
• An ftpmasters sprint is being organized and I've been happy to approve its budget. Help is still needed on the -sprints list to keep up with the organization part of sprints, including activities like documenting sprints to show donors what we do with their help.

• to stop the absurdity of not using the official logo ("with Debian") as part of our official theme, I advanced a bit on the topic of relicensing the logo under a DFSG-free license. I sought a second legal advice to SFLC (as requested by the SPI board). They confirm we can safely do the relicensing (without undermining our rights on contained marks) under a license like dual LGPLv3+ / CC-BY-SA, provided that a suitable trademark policy is in place
• which is why I've posted to -project a trademark policy draft, based on legal advice from SFLC. I've gather useful feedback already, but more is welcome. Note that, as Russ very eloquently put it, we do not particularly enjoy thinking about which restrictions we put on the usage of our marks. But given we do have (and use) those marks, we should better empower the legal owners (SPI in this case) to properly defend them. Our specification for the policy to SFLC has been "as free as possible", and that is what we're trying to achieve.

• I got the legal advice we asked about the possibility of turning mentors.debian.net into an official service. The worry there was about the potential copyright infringements by mentees. In the end, we don't need to worry about that, provided we've clear contact points (and "reasonable" timing ) for removing infringing material once it's been reported, and that we declare our public policy about that. I've a draft policy document to start with. I'll soon contact mentors.d.n to adapt it where needed and have it vetted by SPI before going live.
• I've worked with GNOME maintainers (thanks in particular to Jordi Mallach) to rework the mixed Debian/GNOME logo on their alioth project page, to stay on the safe side and avoid any ambiguity wrt GNOME trademark policy.

• we've been happy to accept an invitation to attend the GNOME Advisory Board meeting at GUADEC: Jord (thanks, again!) kindly accepted to represent Debian there. An early report has been posted on his blog, a more detailed one is forthcoming to -project.
• OSI has discussed with their affiliates the possibility of signing the Declaration of Internet Freedom. On behalf of Debian, I've vouched for it. By the way, I'm serving pro tempore as Debian liaison at OSI, but if there are people interested in doing that, I'll be happy to consider handing over the responsibility to other (it's a quite lightweight one, at present).

 g_signal_connect(tree_view, "button-press-event", 
   G_CALLBACK(view_on_button_pressed), NULL);

gboolean view_on_button_pressed(GtkWidget *tree_view, 
                                GdkEventButton *event, 
                                gpointer user_data)  
  GtkTreeSelection *selection;
  GtkTreePath *tree_path;
  GtkTreeModel *tree_model;
  GtkTreeIter tree_iter;
  gchar *name;
 
  if (event->type == GDK_BUTTON_PRESS && event->button == 3)  
    tree_model = gtk_tree_view_get_model(GTK_TREE_VIEW(tree_view));
    if (gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(tree_view),
          (int)event->x, (int)event->y,
          &tree_path, NULL, NULL, NULL))  
      if (gtk_tree_model_get_iter(tree_model, &tree_iter, tree_path))  
        gtk_tree_model_get(tree_model, &tree_iter, NAME_COLUMN, &name, -1);
        g_print("rc name is %s\n", name);
       
     
   

• Line 1:The callback s widget is the GtkTreeView widget we connected the signal with
• Line 10:Checks the event was a button press and button #3 (right button)
• Line 11: Find the GtkTreeModel from the given GtkTreeView
• Lines 12-14: Get the GtkTreePath that the right-click was sitting at by using the event coordinates.
• Line 15: Convert the GtkTreePath into a GtkTreeIter
• Line 16: Find the actual value we put into this row.

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• [1] http://www.samharris.org/blog/item/the-fall-of-jonah-lehrer

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• [1] http://www.hetzner.de/en/hosting/produktmatrix/rootserver-produktmatrix-ex
• [2] https://robot.your-server.de/order/market

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• I uploaded dpkg 1.16.7 with an important bugfix for a regression.
• I initiated a new round of discussions about how we were going to solve the problem that source packages with Multi-Arch: same binary packages can t be individually bin-nmued.
• Following that discussion, I opened a bunch of bugs to plan/discuss the transition of changelog/copyright files within the package metadata (#681289 on debian-policy, #681293 on apt-listchanges, #681295 on www.debian.org for packages.debian.org).
• I also filed #681292 on sbuild to get it to use dpkg s new syntax for bin-nmus. It will allow us to do binary-only rebuilds with arbitrary versions (instead of only +b1 suffixes). Ubuntu could use this for their +rebuild1, we could use this to build backports which do not require source changes (and share the common source package instead of duplicating it). It can also be useful if we ever get to the situation where transitions are prepared in external repositories and where we want bin-nmus in those repositories to have unique versions (even though the same package might be bin-nmued in multiple repositories in case of concurrent transitions).
• I filed an unblock request for dpkg once it was almost 10 days old.
• I did reconsider the bug #316521 where dpkg looses track of some shared directories with manually created files and proposed an updated patch. No words from Guillem on the patch yet. Fixing this would help to fix a bunch of piuparts issues.
• And just before my vacation, I filed many bugs against dpkg itself, effectively moving some of the items that accumulated in my TODO in a public place where others can help (I ll be happy to mentor anyone who wants to tackle one of these):
  • #681443: dpkg-source commit should be able to merge changes in an existing patch
  • #681470: dpkg-shlibdeps: should also scan Build-Depends-Arch for minimal versions
  • #681474: Dpkg::Vendor: should support /etc/os-release and /etc/os-release.d/*
  • #681477: dpkg-vendor: implement select-closest command
  • #681480: base-files: Provide HOME_URL, SUPPORT_URL and BUG_REPORT_URL in /etc/os-release
  • #681489: base-files: Add /etc/os-release.d/debian and make it easy to provide supplementary /etc/os-release.d/* files
• In #595112 we discussed the specifics of a new dpkg-mainstscript-helper feature to move a conffile from one package to another.

No comment Liked this article? Click here. My blog is Flattr-enabled.

• Jacob Appelbaum s keynote about Tor brought up some surprising facts about how the project has outgrown its past performance problems and how useful it was during e. g. the Arab revolution
.
• Philip Whitnall s presented Bendy Bus, a tool to mock D-Bus services for both unit and fuzz testing. He successfully used it to find and replicate bugs in Evolution (by mocking evolution-data-server) as well as libfolks (by mocking the telepathy daemons). It should work just as well to mock system services like upower or NetworkManager to test the UI bits that use it. This is a topic which has been on my wishlist for a long time already, so I m happy that there is already an existing solution out there. We might have to add some small features to it, but it s by and large what I had in mind, and in the discussion afterwards Philip said he d appreciate patches against it.
• Christophe Fergeau showed how to easily do Windows builds and installers from GNOME tarballs with MinGW-w64, without having to actually touch/use Windows (using cross-building and running tests etc. under wine). I found it surprising how easy that actually is, and it should not be hard to integrate that in a jhbuild-like setup, so that it does not keep breaking every time.
• Colin Walters gave an introduction to OSTree, a project to build bootable images from kernel/plumbing/desktop upstream git heads on a daily basis. This is mostly to avoid the long delays that we otherwise have with doing upstream releases, packaging them, and getting them into a form that can safely be tested by users. In an afterwards discussion we threw some ideas around how we can integrate existing and future tests into this (something in spirit like our autopkgtest). This will be the area where I ll put most focus on in the next time.
• Adam Dingle of yorba fame shared his thoughts about how we can crowdfunding of Free Software Projects work in practice, comparing efforts like codefoundry and kickstarter. Of course he does not have a solution for this yet, but he raised some interesting concerns and it spun off lots of good discussions over lunchtime.
• Last but not least, the sport event on Saturday evening was awesome! In hindsight I was happy to not have signed up for soccer, as people like Bastian or Jordi played this really seriously. I participated in the Basketball competition instead, which was the right mix of fun and competition without seriously trying to hurt each other.

• [1] http://zfsonlinux.org/
• [2] http://zfsonlinux.org/faq.html
• [3] https://github.com/dajhorn/pkg-zfs/wiki/HOWTO-install-Ubuntu-to-a-Native-ZFS-Root-Filesystem

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Diary

July 2

• playing around with syntactic dependency graphs and how to use them to flatten dependencies

July 4

• make work with dose 3.0.2
• add linux-amd64 to source architectures
• remove printing in build_compile_rounds
• catch Not_found exception and print warning
• use the whole installation set in crosseverything.ml instead of flattened dependencies
• detect infinite loop and quit in crosseverything.ml
• use globbing in _tags file
• use wildcards and patsubst in makefile

July 5

• throw a warning if there exist binary packages without source packages
• add string_of_list and string_of_pkglist and adapt print_pkg_list and print_pkg_list_full to use them
• fix and extend flatten_deps - now also tested with Debian Sid

July 6

• do not exclude the crosscompiled packages from being compiled in crosseverything.ml
• clean up basebuildsystem.ml, remove old code, use BootstrapCommon code
• clean up basenocycles.ml, remove unused code and commented out code
• add option to print statistics about the generated dependency graph
• implement most_needed_fast_wrong as well as most_needed_slow_correct and make both available through the menu

July 7

• allow to investigate all scc, not only the full graph and the scc containing the investigated package
• handle Not_found in src_list_from_bin_list with warning message
• handle the event of the whole archive actually being buildable
• replace raise Failure with failwith
• handle incorrectly typed package names
• add first version of reduced_dist.ml to create a self-contained mini distribution out of a big one

July 8

• add script to quickly check for binary packages without source package
• make Debian Sid default in makefile
• add *.d.byte files to .gitignore
• README is helpful now
• more pattern matching and recursiveness everywhere

July 9

• fix termination condition of reduced_dist.ml
• have precise as default ubuntu distribution
• do not allow to investigate an already installable package

July 10

• milestone: show all cycles in a graph
• add copyright info (LGPL3+)

July 11

• advice to use dose tools in README

July 16

• write apt_pkg based python filter script replacing grep-dctrl

July 17

• use Depsolver.listcheck more often
• add dist_graph.ml
• refactor dependency graph code into its own module

July 18

• improve package selection for reduced_dist.ml
• improve performance of cycle enumeration code

July 20

• implement buildprofile support into dose3

July 22

• let dist_graph.ml use commandline arguments

July 23

• allow dose3 to generate source package lists without Build- Depends Conflicts -Indep

July 29

• implement crosscompile support into dose3

Results

Readme There is not yet a writeup on how everything works and how all the pieces of the code work together but the current README file provides a short introduction on how to use the tools.

• build and runtime dependencies
• compile instructions
• execution examples for each program
• step by step guide how to analyze the dependency situation
• explanation of general commandline options

A detailed writeup about the inner workings of everything will be part of a final documentation stage.

License All my code is now released under the terms of the LGPL either version 3, or (at your option) any later version. A special linking exception is made to the license which can be read at the top of the provided COPYING file. The exception is necessary because Ocaml links statically, which means that without that exception, the conditions of distribution would basically equal GPL3+.

reduced_dist.ml Especially the Debian archive is huge and one might want to work on a reduced selection of packages first. Having a smaller selection of the archive would be significantly faster and would also not add thousands of packages that are not important for an extended base system. I call a reduced distribution a set of source packages A and a set of binary packages B which fulfill the following three properties:

• all source packages A must be buildable with only binary packages B being available
• all binary packages B except for architecture:all packages must be buildable from source packages A

The set of binary packages B and source packages A can be retrieved using the reduced_dist program. It allows to either build the most minimal reduced distribution or one that includes a certain package selection. To filter out the package control stanzas for a reduced distribution from a full distribution, I originally used a call to grep-dctrl but later replaced that by a custom python script called filter-packages.py. This script uses python-apt to filter Packages and Sources files for a certain package selection.

dist_graph.ml It soon became obvious that there were not many independent dependency cycle situation but just one big scc that would contain 96% of the packages that are involved in build dependency cycles. Therefor it made sense to write a program that does not iteratively build the dependency graph starting from a single package, but which builds a dependency graph for a whole archive.

Cycles I can now enumerate all cycles in the dependency graph. I covered the theoretical part in another blog post and wrote an email about the achievement to the list. Both resources contain more links to the respective sourcecode. The dependency graph generated for Debian Sid has 39486 vertices. It has only one central scc with 1027 vertices and only eight other scc with 2 to 7 vertices. All the other source and binary packages in the dependency graph for the archive are degenerate components of length one. Obtaining the attached result took 4 hours on my machine (Core i5 @ 2.53GHz). 1.5 h of that were needed to build the dependency graph, the other 2.5 hours were needed to run johnson's algorithm on the result. Memory consumption of the program was at about 700 MB. It is to my joy that apparently the runtime of the cycle finding algorithm for a whole Debian Sid repository as well as the memory requirements are within orders of magnitude that are justifiable when being run on off-the-shelf hardware. It must also be noted that nothing is optimized for performance yet. A list of all cycles in Debian Sid up to length 4 can be retrieved from this email. This cycle analysis assumes that only essential packages, build-essential and dependencies and debhelper are available. Debhelper is not an essential or build-essential package but 79% of the archive build-depends on it. The most interesting cycles are probably those of length 2 that need packages that they build themselves. Noticeable examples for these situations are vala, python, mlton, fpc, sbcl and ghc. Languages seem love to need themselves to be built.

Buildprofiles There is a long discussion of how to encode staged build dependency information in source packages. While the initial idea was to use Build-Depends-StageN fields, this solution would duplicate large parts of the Build-Depends field, which leads to bitrot as well as it is inflexible to possible other build "profiles". To remedy the situation it was proposed to use field names like Build-Depends[stage1 embedded] but this would also duplicate information and would break with the rfc822 format of package description files. A document maintained by Guillem Jover gives even more ideas and details. Internally, Patrick and me decided for another idea of Guillem Jover to annotate staged build dependencies. The format reads like:

Build-Depends: huge (>= 1.0) [i386 arm] <!embedded !bootstrap>, tiny

So each build profile would follow a dependency in <> "brackets" an have a similar format as architecture options. Patrick has a patch for dpkg that implements this functionality while I patched dose3.

Dropping Build-Depends-Indep and Build-Conflicts-Indep When representing the dependencies of a source package, dose3 concatenates its Build-Depends and Build-Depends-Indep dependency information. So up to now, a source package could only be compiled, if it manages to compile all of its binary packages including architecture:all packages. But when bootstrapping a new architecture, it should be sufficient to only build the architecture dependent packages and therefor to only build the build-arch target in debian/rules and not the build-indep target. Only considering the Build-Depends field and dismissing the Build-Depends-Indep field, reduced the main scc from 1027 vertices to 979 vertices. The amount of cycles up to length four reduced from 276 to 206. Especially the cycles containing gtk-doc-tools, doxygen, debiandoc-sgml and texlive-latex-base got much less. Patrick managed to add a Build-Depends-Indep field to four packages so far which reduced the scc further by 14 vertices down to 965 vertices. So besides staged build dependencies and cross building there is now a third method that can be applied to break dependency cycles: add Build-Depends-Indep information to them or update existing information. I submitted a list of packages that have a binary-indep and/or a build-indep target in their debian/rules to the list. I also submitted a patch for dose3 to be able to specify to ignore Build-Depends-Indep and Build-Conflicts-Indep information.

Dose3 crossbuilding So far I only looked at dependency situations in the native case. While the native case contains a huge scc of about 1000 packages, the dependency situation will be much nicer when cross building. But dose3 was so far not able to simulate cross building of source packages. I wrote a patch that implements this functionality and will allow me to write programs that help analyze the cross-situation as well.

Debconf Presentation Wookey was giving a talk at debconf12 for which I was supplying him with slides. The slides in their final version can be downloaded here

Future Patrick maintains a list of "weak" build dependencies. Those are dependencies that are very likely to be droppable in either a staged build or using Build-Depends-Indep. I must make use of this list to make it easier to find packages that can easily be removed of their dependencies. I will have to implement support for resolving the main scc using staged build dependencies. Since it is unlikely that Patrick will be fast enough in supplying me with modified packages, I will need to create myself a database of dummy packages. Another open task is to allow to analyze the crossbuilding dependency situation. What I'm currently more or less waiting on is the inclusion of my patches into dose3 as well as a decision on the buildprofile format. More people need to discuss about it until it can be included into tools as well as policy. Every maintainer of a package can help making bootstrapping easier by making sure that as many dependencies as possible are part of the Build-Depends-Indep field.

• Probably the biggest improvement would be generating javascript from haskell code, so the type safety extends to the javascript side. There have been many tries at doing this, the first one I'm really tempted to use is Fay. Rather than build a heavy haskell runtime on top of javascript, it essentially uses javascript as its runtime, and offloads type checking to GHC. This lets it generate javascript code that is short and often comprehensible enough to give insights into what the original haskell code does. I'm betting this will be integrated into Yesod eventually. They have an active wiki page about it.
• There's a WAI library for building local webapps with Yesod, but it was not suitable for my needs (for one thing, it lacks security; for another it kills the haskell program when the web page is closed); so I built my own webapp library. A problem with my current pace of development is that I'm building lots of reusable libraries, but I don't have the time to stabalize them and make them generally available. That one goes in the pile of 2k+ lines of such code.
• Yesod needs a version of the Hamlet markup that can be edited by people who only understand html. That means it should allow closing tags, and tabs, and not have nasty whitespace gotchas. I think this would be easy to build, starting from Hamlet. It could be called "Hecate".. I don't have time right now.
• The compile time error messages are often beyond atrocious. Seriously, I'm tempted to write a filter to filter out common patterns where there's one line about a syntax error in a Hamlet file sandwitched in between 150 lines of type error gobbly-gook and generated code.
• Some really nice things could be done integrating Yesod with Bootstrap. Like the ability to build entire sites by just composing together Bootstrap components, with no need to write a single line of html or css. I'm very tempted to try to build this library.

    webpage = bootstrap Dynamic $ do
        setTitle "FooCorp"
        login <- getLogin
        navbar [FixedTop] $ do
            brand "FooCorp"
            link AboutR
            link BlogR
            nav [PullRight] $
                link . maybe LoginR ProfileR login
        div [ContainerFluid] $ content login
        where
            content Nothing = heroUnit $ do
                para $ "We're the FooCorp for you."
                button "Register Today" [Primary, Large] SignUpR
                carousel
                    [ amazingFeatures
                    , aboutFooCorp
                    , pricing
                    ]
            content (Just user)  = do
                para $ "Welcome back " ++ name user ++ "!"
                showProfile user

I came one day early to participate, as Debian's representative, at the yearly GNOME Advisory Board meeting, for the first time. It was a positive experience, which helped me get a grasp of the big picture of what the GNOME Foundation does. I also had the pleasure of visiting Igalia's awesome offices in the city, and puting faces to many names during the meeting. I presented an overview of Debian's relation to GNOME, how our packaging team works and what are our goals and biggest problems as a GNOME downstream. We stirred some good debate as some other Advisory Board members share part of our problems. I should be posting a summary of what happened there for debian-project@ldo as soon as I have the time to scribble it. I've met with GNOME Hispano people I hadn't seen since 2004 or 2006 in the best case, and catched up with many of them. I've also met many GPUL members I had know for over a decade via IRC, but never had met in person, and it was about time. And of course, I've got to known a good number of my new workmates at Collabora, and had fun with them around the conference, the beach and the numerous post-conference events. Last, but not least, I ended up participating in the GNOME Olympics, substituting Rodrigo in Team B Core Dumped , along with Stefano, John, Bastien, Chema and Adam. WE WON, not thanks to me, but the statistics shine: I've won all FreeFA World Cups I've played :P so here's a PROtip: if you want to win next year, be sure to be my team mate, and more importantly, be sure Adam is not your rival. :) Unfortunately, I'm only attending the core days so tonight I'll be flying back to Madrid on my way home in Val ncia. See you next year! A Coru a is a city that has impressed me quite a bit, and I'm looking forward to coming back for some more standard vacation at some point. :)

• awesome, written in C, configurable and extensible in Lua,
• StumpWM, written, configurable and extensible in Common Lisp,
• xmonad, written, configurable and extensible in Haskell.

Awesome configuration Without a configuration file, awesome does nothing. It does not come with any hard-coded behavior: everything needs to be configured through its Lua configuration file. Of course, a default one is provided but you can also start from scratch. If you like to control your window manager, this is somewhat wonderful. awesome is well documented. The wiki provides a FAQ, a good introduction and the API reference is concise enough to be read from the top to the bottom. Knowing Lua is not mandatory since it is quite easy to dive into such a language. I have posted my configuration on GitHub. It should not be used as is but some snippets may be worth to be stolen and adapted into your own configuration. The following sections put light on some notable points.

Keybindings Ten years ago was the epoch of scavanger hunts to recover IBM Model M keyboards from waste containers. They were great to type on and they did not feature the infamous Windows keys. Nowadays, this is harder to get such a keyboard. All my keyboards now have Windows keys. This is a major change with respect to configure a window manager: the left Windows key is mapped to Mod4 and is usually unused by most applications and can therefore be dedicated to the window manager. The main problem with the ability to define many keybindings is to remember the less frequently used one. I have monkey-patched awful.key module to be able to attach a documentation string to a keybinding. I have documented the whole process on the awesome wiki.

Quake console A Quake console is a drop-down terminal which can be toggled with some key. I was heavily relying on it in FVWM. I think this is still a useful addition to any awesome configuration. There are several possible solutions documented in the awesome wiki. I have added my own¹ which works great for me.

XRandR XRandR is an extension which allows to dynamically reconfigure outputs: you plug an external screen to your laptop and you issue some command to enable it:

$ xrandr --output VGA-1 --auto --left-of LVDS-1

awesome detects the change and will restart automatically. Laptops usually come with a special key to enable/disable an external screen. Nowadays, this key does nothing unless configured appropriately. Out of the box, it is mapped to XF86Display symbol. I have associated this key to a function that will cycle through possible configurations depending on the plugged screens. For example, if I plug an external screen to my laptop, I can cycle through the following configurations:

• only the internal screen,
• only the external screen,
• internal screen on the left, external screen on the right,
• external screen on the left, internal screen on the right,
• no change.

The proposed configuration is displayed using naughty, the notification system integrated in awesome.

Widgets I was previously using Conky to display various system-related information, like free space, CPU usage and network usage. awesome comes with widgets that can fit the same use. I am relying on vicious, a contributed widget manager, to manage most of them. It allows one to attach a function whose task is to fetch values to be displayed. This is quite powerful. Here is an example with a volume widget:

local volwidget = widget(  type = "textbox"  )
vicious.register(volwidget, vicious.widgets.volume,
         '<span font="Terminus 8">$2 $1%</span>',
        2, "Master")
volwidget:buttons(awful.util.table.join(
             awful.button(   , 1, volume.mixer),
             awful.button(   , 3, volume.toggle),
             awful.button(   , 4, volume.increase),
             awful.button(   , 5, volume.decrease)))

You can also use a function to format the text as you wish. For example, you can display a value in red if it is too low. Have a look at my battery widget for an example.

Miscellaneous While I was working on my awesome configuration, I also changed some other desktop-related bits.

Keyboard configuration I happen to setup all my keyboards to use the QWERTY layout. I use a compose key to input special characters like . I have also recently use Caps Lock as a Control key. All this is perfectly supported since ages by X11 I am also mapping the Pause key to XF86ScreenSaver key symbol which will in turn be bound to a function that will trigger xautolock to lock the screen. Thanks to a great article about extending the X keyboard map with xkb, I discovered that X was able to switch from one layout to another using groups². I finally opted for this simple configuration:

$ setxkbmap us,fr '' compose:rwin ctrl:nocaps grp:rctrl_rshift_toggle
$ xmodmap -e 'keysym Pause = XF86ScreenSaver'

I switch from us to fr by pressing both left Control and left Shift keys.

Getting rid of most GNOME stuff Less than one year ago, to take a step forward to the future, I started to heavily rely on some GNOME components like GNOME Display Manager, GNOME Power Manager, the screen saver, gnome-session, gnome-settings-daemon and others. I had numerous problems when I tried to setup everything without pulling the whole GNOME stack. At each GNOME update, something was broken: the screensaver didn t start automatically anymore until a full session restart or some keybindings were randomly hijacked by gnome-settings-daemon. Therefore, I have decided to get rid of most of those components. I have replaced GNOME Power Manager with system-level tools like sleepd and the PM utilities. I replaced the GNOME screensaver with i3lock and xautolock. GDM has been replaced by SLiM which now features ConsoleKit support³. I use ~/.gtkrc-2.0 and ~/.config/gtk-3.0/settings.ini to configure GTK+. The future will wait.

Terminal color scheme I am using rxvt-unicode as my terminal with a black background (and some light transparency). The default color scheme is suboptimal on the readability front. Sharing terminal color schemes seems a popular activity. I finally opted for the derp color scheme which brings a major improvement over the default configuration. I have also switched to Xft for font rendering using DejaVu Sans Mono as my default font (instead of fixed) with the following configuration in ~/.Xresources:

Xft.antialias: true
Xft.hinting: true
Xft.hintstyle: hintlight
Xft.rgba: rgb
URxvt.font: xft:DejaVu Sans Mono-8
URxvt.letterSpace: -1

The result is less crisp but seems a bit more readable. I may switch back in the future.

Next steps My reliance to the mouse has been greatly reduced. However, I still need it for casual browsing. I am looking at luakit a WebKit-based browser extensible with Lua for this purpose.

---

1. The console gets its own unique name. This allows awesome to reliably detect when it is spawned, even on restart. It is how the Quake console works in the mod of FVWM I was using.
2. However, the layout is global, not per-window. If you are interested by a per-window layout, take a look at kbdd.
3. Nowadays, you cannot really survive without ConsoleKit. Many PolicyKit policies do not rely on groups any more to grant access to your devices.

• Procedural languages: Obviously C, but also Unix shell
• OO languages: Python, Java, plenty of other fine choices
• Functional: Lisp, Scheme, Haskell (also the only lazy and pure language on this list)
Having said all that, more important than a choice of book or language is experience. I have heard people suggest that it takes 10,000 hours of practice to become a superstar at something, whatever that something is, and I wouldn t doubt it. Seth Godin discusses that a bit, with some criticism of the idea too. So that leads to the most important piece of advice: dive in to whatever your interest is. Experiment, write code, put theory into practice in a way that holds interest and excitement. People that try to do things they don t enjoy don t seem to stick with them as long or execute as well, and thus will never become great.