After reading up on a eye-opening blog from Petter Reinholdtsen about laptop batteries, or more specifically Lithium-Ion laptop batteries, I figured I needed to try out the "TLP Linux Advanced Power Management" that I had been keeping an eye on for a while. tlp is yet another tool to control power usage on laptops (mostly Thinkpad, mine is a X120e). The novelty of tlp is the "hands off" approach: everything should be automatically configured for you... Obviously, that means I then went on working for a few hours on breaking and fixing my laptop in random operations. I opened a bunch of pull requests on the interesting battery status package that Petter produced to make it work with my setup and make it display graphs directly (instead of into a file). I also rewrote the graphing tool in Python with SciPy in order to have cleaner labels and be able to deduce the date at which a battery would be completely unusuable because it can't recharge high enough. (At the time of writing, the battery estimated death time is december 7th, but that data is skewed because of a quick change in the battery charge after the BIOS upgrade, below.) I then went on to try to limit my laptop charging to 80%, since this seems to make the battery last longer (sources from Petter: 1, 2, 3). Unfortunately, even after building a local (and trivial) backport of the tlp package to Debian stable (8.2/Jessie), I still couldn't access those controls, as TLP is really just a set of shell scripts that glue a bunch of stuff together.

The backport was simply:

apt-get source tlp
cd tlp*/
debuild
sudo dpkg -i ../tlp*.deb

I read here and there (and in Petter's post) that I needed the tp-smapi-dkms package, so I went ahead an installed it:

sudo apt install tp-smapi-dkms

(Yes, Jessie has a neat apt command now, it's great, upgrade now.) Unfortunately, this still didn't work. I think the error back then was something like:

thinkpad_ec: thinkpad_ec_request_row: arg0 rejected: (0x01:0x00)->0x00
thinkpad_ec: thinkpad_ec_read_row: failed requesting row: (0x01:0x00)->0xfffffffb
thinkpad_ec: initial ec test failed

I have seen suggestions here and there to try the acpi-call-dkms package, but that was useless as it doesn't support my model (but may work with others!). The error there was:

acpi_call: Cannot get handle: Error: AE_NOT_FOUND

Note: I still have it installed - it's unclear what impact it has, and I do not want to break my current setup.

So I then started to look at upgrading my BIOS, for some reason. I was running version 1.13 (8FET29WW) from 05/06/2011. I was able to update to 1.17 (8FET33WW) from 11/07/2012, using the memdisk binary from the syslinux-common package, with some help from the quite useful grub-imageboot package:

sudo apt install syslinux-common grub-imageboot
wget https://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles/8fuj10uc.iso
sudo mkdir /boot/images
sudo mv 8fuj10uc.iso /boot/images
sudo reboot

I found the image on the Thinkpad x120e support page from Lenovo (which happily bounces around, so don't rely on the above URLs too much). When I rebooted, I was offered to boot from the image by grub, which went on fine, considering it was running some version of DOS, which is always a bit scary considering it is software that is somewhat almost as old as me.

I wish I could have installed some free software in the BIOS instead of the outdated crap that Lenovo provides, but unfortunately, it seems this will never be possible with Libreboot or Coreboot, mostly because Intel is evil and installs backdoors in all their computers. Fun times.

Fortunately and surprisingly, the update worked and went on pretty smoothly. After that, I was able to set the charge limit with:

echo 80   sudo tee /sys/devices/platform/smapi/BAT0/stop_charge_thresh

Amazing! I had almost forgotten why I almost bricked my system on a thursday, good thing that worked! Now the fun part was that, after some reboots or something I did, I am not sure what, the above stopped working: I couldn't load the drivers at all anymore, dmesg treating me with a nasty:

thinkpad_ec: thinkpad_ec_read_row: failed requesting row: (0x01:0x00)->0xfffffff0
thinkpad_ec: initial ec test failed

Now that is some obscure error message material! Fun stuff. I tried uninstalling tlp, the smapi modules, the acpi-call modules, rebooting, turning the machine off, removing the battery, nothing worked. Even more hilarious, the charge controler was now stuck at 80%: I had artificially destroyed 20% of the battery capacity in software. Ouch. I think this may have been related to uninstalling the tp-smapi-dkms package without unloading it at first. I found some weird entries in my kern.log like this:

tp_smapi unloaded.
thinkpad_ec: thinkpad_ec_read_row: failed requesting row: (0x14:0x00)->0xfffffff0
hdaps: cannot power off
hdaps: driver unloaded.
thinkpad_ec: unloaded.

I think that after that point, I couldn't load either module, not even thinkpad_ec... After tearing out a few more hairs and hammering my head on the keyboard randomly, I thought I could just try another BIOS upgrade, just for the fun of it. Turns out you actually can't rerun the upgrade, but you can change the model number through the same software, and this seems to reset some stuff. So I went back in the ISO image I had loaded earlier, and went on to change the model number (actually setting it to the same value, but whatever, it still ran the update). It turns out this seems to have reset a bunch of stuff and now everything works. I can use tlp setcharge and all the neat tools go well. The two key commands are:

# limit charging to 80% of the battery, but not lower than 40%
sudo tlp setcharge 40 80
# clear the above setting and just charge the battery to 100%
sudo tlp fullcharge

It seems that the 40% bit isn't supported by my laptop, but whatever: the battery stays charged when on AC power anyways, so I don't really understand what the setting is for in the first place. The error there is:

smapi smapi: smapi_request: SMAPI error: Function is not supported by SMAPI BIOS (func=2116)
smapi smapi: __get_real_thresh: cannot get start_thresh of bat=0: Function is not supported by SMAPI BIOS

The second command is what I will need to remember to run before I unplug the laptop for a trip. I suspect this will be really annoying and I may end up disabling all this stuff and just yank the power cable out when the battery reaches 80%, by hand, when I need to. But it was a fun geeking out, and hopefully this will be useful for others. And of course, the graphs from Petter will be interesting in a few months... Before the BIOS upgrade, the battery capacity was reported as 100% (actually, at 100.03%, which was strange). Now, the capacity is at 98.09%, which is probably just a more accurate reading that was fixed in the BIOS upgrade. Finally, also see the useful thinkwiki troubleshooting page and especially their interesting BIOS upgrade documentation which inspired me to write my own version. I would have gladly contributed to theirs, but I seem to have lost my password on this site, with no recovery possible... The arch linux wiki has obviously excellent documentation as well, as usual.

I like Italian food and Mexican food, he said. Where are you from? she asked. Yemen, but I like Italian food and Mexican food, he answered. You don't like Yemeni food? she asked. Eh, well, it's the thing you grow up with, he replied. Do you know Yemeni food? Yes, she said, I like . Oh, is good if you like meat. If you like vegetables, try . Why wouldn't I like meat? she demanded. You know, every place in Yemen does differently. I like the way they do it in the west of Yemen, near Africa, he said, and proceeded to describe the cooking process.

What happened in the reproducible builds effort this week: Toolchain fixes

• Ben Hutchings uploaded linux-tools/4.2-1 which makes the tarball generated by genorig.py reproducible.

Packages fixed The following 22 packages became reproducible due to changes in their build dependencies: breathe, cdi-api, geronimo-jpa-2.0-spec, geronimo-validation-1.0-spec, gradle-propdeps-plugin, jansi, javaparser, libjsr311-api-java, mac-widgets, mockito, mojarra, pastescript, plexus-utils2, powerline, python-psutil, python-sfml, python-tldap, pythondialog, tox, trident, truffle, zookeeper. The following packages became reproducible after getting fixed:

• cloudprint/0.14-1 uploaded by David Steele, original patch by Chris Lamb.
• cpl-plugin-sinfo/2.6.5+dfsg-2 by Ole Streicher.
• fonts-stix/1.1.1-4 uploaded by Hugo Lefeuvre, original patch by Dhole.
• gstreamermm-1.0/1.4.3+dfsg-5 by Philip Rinn.
• hspell/1.2-3 uploaded by Tzafrir Cohen, original patch by Reiner Herrmann.
• libmodule-extractuse-perl/0.33-2 by gregor herrmann.
• mariadb-10.0/10.0.21-1 by Otto Kek l inen.
• mkvtoolnix/8.4.0-1 uploaded by Christian Marillat, fixed upstream.
• mlpack/1.0.12-5 by Barak A. Pearlmutter.
• module-assistant/0.11.8 by Andreas Beckmann.
• pitivi/0.94-4 uploaded by Sebastian Dr ge, reported by Scott Kitterman.
• privoxy/3.0.23-4 by Roland Rosenfeld.
• qtop/2.3.1-1 uploaded by Hugo Lefeuvre, fixed upstream.
• seyon/2.20c-32 by Santiago Vila.
• subvertpy/0.9.3-2 by Jelmer Vernooij.
• twitter-bootstrap/2.0.2+dfsg-8 by Santiago Vila, reported by Chris Lamb.
• vdr-plugin-remote/0.7.0-1 by Tobias Grimm.

Some uploads fixed some reproducibility issues but not all of them:

• fldigi/3.23.01-1 by Kamal Mostafa.

Patches submitted which have not made their way to the archive yet:

• #799871 on console-data by Chris Lamb: grep all keymap files as text.
• #800007 on anarchism by Holger Levsen: use C locale when converting HTML to text files.
• #800107 on dutch by Chris Lamb: grep wordlist files as text.

diffoscope development The changes to make diffoscope run under Python 3, along with many small fixes, entered the archive with version 35 on September 21th. Another release was made the very next day fixed two encoding-related issues discovered when running diffoscope on more Debian packages. strip-nondeterminism development Version 0.12.0 now preserves file permissions on modified zip files and dh_strip_nondeterminism has been made compatible with older debhelper. disorderfs development Version 0.3.0 implemented a multi-user mode that was required to build Debian packages using disorderfs. It also added command line options to control the ordering of files in directory (either shuffled or reversed) and another to do arbitrary changes to the reported space used by files on disk. A couple days later, version 0.4.0 was released to support locks, flush, fsync, fsyncdir, read_buf, and write_buf. Almost all known issues have now been fixed. reproducible.debian.net disorderfs is now used during the second build. This makes file ordering issue very easy to identify as such. (h01ger) Work has been done on making the distributed build setup more reliable. (h01ger) Documentation update Matt Kraii fixed the example on how to fix issues related to dates in Sphinx. Recent Sphinx versions should also be compatible with SOURCE_DATE_EPOCH. Package reviews 53 reviews have been removed, 85 added and 13 updated this week. 46 packages failing to build from source has been identified by Chris Lamb, Chris West, and Niko Tyni. Chris Lamb was the lucky reporter of bug #800000 on vdr-plugin-prefermenu. Issues related to disorderfs are being tracked with a new issue.

Honey Mojito

• 12 oz. honey
• 7 medium limes
• bag crushed ice
• small bouquet fresh mint
• water
• light rum
• sparkling water

Combine 12 oz. of honey with 8 oz. of warm water. Stir mixture together until the honey has completely dissolved. Juice limes in a juicer and pour into the honey and water. Squeeze the bunch of mint sprigs and add to a pitcher of crushed ice. Pour the honey /lime mixture over the ice. Stir and top with sparkling water. Add more honey , water, limes, or rum to your taste. Enjoy! Serves 2

VLANd is a python program intended to make it easy to manage port-based VLAN setups across multiple switches in a network. It is designed to be vendor-agnostic, with a clean pluggable driver API to allow for a wide range of different switches to be controlled together. There's more information in the README file. I've just released v0.4, with a lot of changes included since the last release:

• Large numbers of bugfixes and code cleanups
• Code changes for integration with LAVA:
  • Added db.find_lowest_unused_vlan_tag()
  • create_vlan() with a tag of -1 will find and allocate the first unused tag automatically
• Add port numbers as well as names to the ports database, to give human-recognisable references. See README.port-numbering for more details.
• Add tracking of trunks, the inter-switch connections, needed for visualisation diagrams.
• Add a simple http-based visualisation feature:
  • Generate network diagrams on-demand based on the information in the VLANd database, colour-coded to show port configuration
  • Generate a simple website to reference those diagrams.
• Allow more ports to be seen on Catalyst switches
• Add a systemd service file for vland

VLANd is Free Software, released under the GPL version 2 (or any later version). For now, grab it from git; tarballs will be coming shortly.

When I get a new laptop, the battery life time at the start is OK. But this do not last. The last few laptops gave me a feeling that within a year, the life time is just a fraction of what it used to be, and it slowly become painful to use the laptop without power connected all the time. Because of this, when I got a new Thinkpad X230 laptop about two years ago, I decided to monitor its battery state to have more hard facts when the battery started to fail. First I tried to find a sensible Debian package to record the battery status, assuming that this must be a problem already handled by someone else. I found battery-stats, which collects statistics from the battery, but it was completely broken. I sent a few suggestions to the maintainer, but decided to write my own collector as a shell script while I waited for feedback from him. Via a blog post about the battery development on a MacBook Air I also discovered batlog, not available in Debian. I started my collector 2013-07-15, and it has been collecting battery stats ever since. Now my /var/log/hjemmenett-battery-status.log file contain around 115,000 measurements, from the time the battery was working great until now, when it is unable to charge above 7% of original capacity. My collector shell script is quite simple and look like this:

#!/bin/sh
# Inspired by
# http://www.ifweassume.com/2013/08/the-de-evolution-of-my-laptop-battery.html
# See also
# http://blog.sleeplessbeastie.eu/2013/01/02/debian-how-to-monitor-battery-capacity/
logfile=/var/log/hjemmenett-battery-status.log
files="manufacturer model_name technology serial_number \
    energy_full energy_full_design energy_now cycle_count status"
if [ ! -e "$logfile" ] ; then
    (
	printf "timestamp,"
	for f in $files; do
	    printf "%s," $f
	done
	echo
    ) > "$logfile"
fi
log_battery()  
    # Print complete message in one echo call, to avoid race condition
    # when several log processes run in parallel.
    msg=$(printf "%s," $(date +%s); \
	for f in $files; do \
	    printf "%s," $(cat $f); \
	done)
    echo "$msg"
 
cd /sys/class/power_supply
for bat in BAT*; do
    (cd $bat && log_battery >> "$logfile")
done

The script is called when the power management system detect a change in the power status (power plug in or out), and when going into and out of hibernation and suspend. In addition, it collect a value every 10 minutes. This make it possible for me know when the battery is discharging, charging and how the maximum charge change over time. The code for the Debian package is now available on github. The collected log file look like this:

timestamp,manufacturer,model_name,technology,serial_number,energy_full,energy_full_design,energy_now,cycle_count,status,
1376591133,LGC,45N1025,Li-ion,974,62800000,62160000,39050000,0,Discharging,
[...]
1443090528,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,
1443090601,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,

I wrote a small script to create a graph of the charge development over time. This graph depicted above show the slow death of my laptop battery. But why is this happening? Why are my laptop batteries always dying in a year or two, while the batteries of space probes and satellites keep working year after year. If we are to believe Battery University, the cause is me charging the battery whenever I have a chance, and the fix is to not charge the Lithium-ion batteries to 100% all the time, but to stay below 90% of full charge most of the time. I've been told that the Tesla electric cars limit the charge of their batteries to 80%, with the option to charge to 100% when preparing for a longer trip (not that I would want a car like Tesla where rights to privacy is abandoned, but that is another story), which I guess is the option we should have for laptops on Linux too. Is there a good and generic way with Linux to tell the battery to stop charging at 80%, unless requested to charge to 100% once in preparation for a longer trip? I found one recipe on askubuntu for Ubuntu to limit charging on Thinkpad to 80%, but could not get it to work (kernel module refused to load). I wonder why the battery capacity was reported to be more than 100% at the start. I also wonder why the "full capacity" increases some times, and if it is possible to repeat the process to get the battery back to design capacity. And I wonder if the discharge and charge speed change over time, or if this stay the same. I did not yet try to write a tool to calculate the derivative values of the battery level, but suspect some interesting insights might be learned from those. Update 2015-09-24: I got a tip to install the packages acpi-call-dkms and tlp (unfortunately missing in Debian stable) packages instead of the tp-smapi-dkms package I had tried to use initially, and use 'tlp setcharge 40 80' to change when charging start and stop. I've done so now, but expect my existing battery is toast and need to be replaced. The proposal is unfortunately Thinkpad specific.

In a few weeks, I will have the opportunity to offer a weekend workshop to selected and motivated high school students¹ to a topic of my choice. My idea is to tell them something about logic, proofs, and the joy of searching and finding proofs, and the gratification of irrevocable truths. While proving things on paper is already quite nice, it is much more fun to use an interactive theorem prover, such as Isabelle, Coq or Agda: You get immediate feedback, you can experiment and play around if you are stuck, and you get lots of small successes. Someone² once called interactive theorem proving the worlds most geekiest videogame . Unfortunately, I don t think one can get high school students without any prior knowledge in logic, or programming, or fancy mathematical symbols, to do something meaningful with a system like Isabelle, so I need something that is (much) easier to use. I always had this idea in the back of my head that proving is not so much about writing text (as in normally written proofs) or programs (as in Agda) or labeled statements (as in Hilbert-style proofs), but rather something involving facts that I have proven so far floating around freely, and way to combine these facts to new facts, without the need to name them, or put them in a particular order or sequence. In a way, I m looking for labVIEW wrestled through the Curry-Horward-isomorphism. Something like this: So I set out, rounded up a few contributors (Thanks!), implemented this, and now I proudly present: The Incredible Proof Machine³ This interactive theorem prover allows you to do perform proofs purely by dragging blocks (representing proof steps) onto the paper and connecting them properly. There is no need to learn syntax, and hence no frustration about getting that wrong. Furthermore, it comes with a number of example tasks to experiment with, so you can simply see it as a challenging computer came and work through them one by one, learning something about the logical connectives and how they work as you go. For the actual workshop, my plan is to let the students first try to solve the tasks of one session on their own, let them draw their own conclusions and come up with an idea of what they just did, and then deliver an explanation of the logical meaning of what they did. The implementation is heavily influenced by Isabelle: The software does not know anything about, say, conjunction ( ) and implication ( ). To the core, everything is but an untyped lambda expression, and when two blocks are connected, it does unification⁴ of the proposition present on either side. This general framework is then instantiated by specifying the basic rules (or axioms) in a descriptive manner. It is quite feasible to implement other logics or formal systems on top of this as well. Another influence of Isabelle is the non-linear editing: You neither have to create the proof in a particular order nor have to manually manage a proof focus . Instead, you can edit any bit of the proof at any time, and the system checks all of it continuously. As always, I am keen on feedback. Also, if you want to use this for your own teaching or experimenting needs, let me know. We have a mailing list for the project, the code is on GitHub, where you can also file bug reports and feature requests. Contributions are welcome! All aspects of the logic are implemented in Haskell and compiled to JavaScript using GHCJS, the UI is plain hand-written and messy JavaScript code, using JointJS to handle the graph interaction. Obviously, there is still plenty that can be done to improve the machine. In particular, the ability to create your own proof blocks, such as proof by contradiction, prove them to be valid and then use them in further proofs, is currently being worked on. And while the page will store your current progress, including all proofs you create, in your browser, it needs better ways to save, load and share tasks, blocks and proofs. Also, we d like to add some gamification, i.e. achievements ( First proof by contradiction , 50 theorems proven ), statistics, maybe a share theorem on twitter button. As the UI becomes more complicated, I d like to investigating moving more of it into Haskell world and use Functional Reactive Programming, i.e. Ryan Trickle s reflex, to stay sane. Customers who liked The Incredible Proof Machine might also like these artifacts, that I found while looking whether something like this exists:

• Easyprove, an interactive tool to create textual proofs by clicking on rules.
• Domino On Acid represents natural deduction rules in propositional logic with and as a game of dominoes.
• Proofscape visualizes the dependencies between proofs as graphs, i.e. it operates on a higher level than The Incredible Proof Machine.
• Proofmood is a nice interactive interface to conduct proofs in Fitch-style.
• Proof-Game represents proofs trees in a sequent calculus with boxes with different shapes that have to match.
• JAPE is an editor for proofs in a number of traditional proof styles. (Thanks to Alfio Martini for the pointer.)
• Logitext, written by Edward Z. Yang, is an online tool to create proof trees in sequent style, with a slick interface, and is even backed by Coq! (Thanks to Lev Lamberov for the pointer.)
• Carnap is similar in implementation to The Incredible Proof Machine (logical core in Haskell, generic unification-based solver). It currently lets you edit proof trees, but there are plans to create something more visual.
• Clickable Proofs is a (non-free) iOS app that incorporates quite a few of the ideas that are behind The Incredible Proof Machine. It came out of a Bachelor s thesis of Tim Selier and covers propositional logic.
• Euclid the game by Kasper Peulen is a nice game to play with geometric constructions.

Back in early 2012 I had been helping with system administration of a number of Debian/Ubuntu-based machines, and the odd Solaris machine, for a couple of years at $DAYJOB. We had a combination of hand-written scripts, documentation notes that we cut n paste d from during installation, and some locally maintained Debian packages for pulling in dependencies and providing some configuration files. As the number of people and machines involved grew, I realized that I wasn t happy with how these machines were being administrated. If one of these machines would disappear in flames, it would take time (and more importantly, non-trivial manual labor) to get its services up and running again. I wanted a system that could automate the complete configuration of any Unix-like machine. It should require minimal human interaction. I wanted the configuration files to be version controlled. I wanted good security properties. I did not want to rely on a centralized server that would be a single point of failure. It had to be portable and be easy to get to work on new (and very old) platforms. It should be easy to modify a configuration file and get it deployed. I wanted it to be easy to start to use on an existing server. I wanted it to allow for incremental adoption. Surely this must exist, I thought. During January 2012 I evaluated the existing configuration management systems around, like CFEngine, Chef, and Puppet. I don t recall my reasons for rejecting each individual project, but needless to say I did not find what I was looking for. The reasons for rejecting the projects I looked at ranged from centralization concerns (single-point-of-failure central servers), bad security (no OpenPGP signing integration), to the feeling that the projects were too complex and hence fragile. I m sure there were other reasons too. In February I started going back to my original needs and tried to see if I could abstract something from the knowledge that was in all these notes, script snippets and local dpkg packages. I realized that the essence of what I wanted was one shell script per machine, OpenPGP signed, in a Git repository. I could check out that Git repository on every new machine that I wanted to configure, verify the OpenPGP signature of the shell script, and invoke the script. The script would do everything needed to get the machine up into an operational stage again, including package installation and configuration file changes. Since I would usually want to modify configuration files on a system even after its initial installation (hey not everyone is perfect), it was natural to extend this idea to a cron job that did git pull , verified the OpenPGP signature, and ran the script. The script would then have to be a bit more clever and not redo everything every time. Since we had many machines, it was obvious that there would be huge code duplication between scripts. It felt natural to think of splitting up the shell script into a directory with many smaller shell scripts, and invoke each shell script in turn. Think of the /etc/init.d/ hierarchy and how it worked with System V initd. This would allow re-use of useful snippets across several machines. The next realization was that large parts of the shell script would be to create configuration files, such as /etc/network/interfaces. It would be easier to modify the content of those files if they were stored as files in a separate directory, an overlay stored in a sub-directory overlay/, and copied into the file system s hierarchy with rsync. The final realization was that it made some sense to run one set of scripts before rsync ing in the configuration files (to be able to install packages or set things up for the configuration files to make sense), and one set of scripts after the rsync (to perform tasks that require some package to be installed and configured). These set of scripts were called the pre-tasks and post-tasks respectively, and stored in sub-directories called pre-tasks.d/ and post-tasks.d/. I started putting what would become Cosmos together during February 2012. Incidentally, I had been using etckeeper on our machines, and I had been reading its source code, and it greatly inspired the internal design of Cosmos. The git history shows well how the ideas evolved even that Cosmos was initially called Eve but in retrospect I didn t like the religious connotations and there were a couple of rewrites on the way, but on the 28th of February I pushed out version 1.0. It was in total 778 lines of code, with at least 200 of those lines being the license boiler plate at the top of each file. Version 1.0 had a debian/ directory and I built the dpkg file and started to deploy on it some machines. There were a couple of small fixes in the next few days, but development stopped on March 5th 2012. We started to use Cosmos, and converted more and more machines to it, and I quickly also converted all of my home servers to use it. And even my laptops. It took until September 2014 to discover the first bug (the fix is a one-liner). Since then there haven t been any real changes to the source code. It is in daily use today. The README that comes with Cosmos gives a more hands-on approach on using it, which I hope will serve as a starting point if the above introduction sparked some interest. I hope to cover more about how to use Cosmos in a later blog post. Since Cosmos does so little on its own, to make sense of how to use it, you want to see a Git repository with machine models. If you want to see how the Git repository for my own machines looks you can see the sjd-cosmos repository. Don t miss its README at the bottom. In particular, its global/ sub-directory contains some of the foundation, such as OpenPGP key trust handling.

Review: Getting Back to Full Employment, by Dean Baker & Jared Bernstein

Publisher:	CEPR
Copyright:	2013
ISBN:	0-615-91836-0
Format:	Kindle
Pages:	116

Getting Back to Full Employment is more of a policy paper than a book. The authors both work for economic think tanks; one of those, the Center for Economic and Policy research (co-founded by Baker), is the publisher of this book. It's also free on the Kindle, another sign that the purpose is more about educating and convincing the public than about selling a non-fiction analysis. I found out about this through Paul Krugman, and if you're a regular reader of Krugman's columns and blog, not much here will be a surprise. Baker and Bernstein are advocating what I would call conventional-liberal economic policy by US standards (which means that it's not really that liberal). The short version is that full employment is vital for improving the economic position of the average person, inflation is nowhere near as much of a risk as people claim, and the best economic action the US government can take at present is to aggressively pursue a full employment strategy without worrying excessively about inflation. If you're at all familiar with this debate, you probably already have an opinion about everything in that summary. I certainly do. If you follow economics at all, this debate has been raging ever since the 2008 financial crisis (and earlier versions of the debate were raging before then). Since I'm a regular Krugman reader, you probably know my opinion: the people who have been crying wolf about the dangers of inflation have been systematically wrong about everything for seven years solid, and it's amazing that anyone is still giving them the time of day. Baker and Bernstein make a similar argument at greater length, and with a more academic tone. The risk of any policy paper like this is that reactions will be almost entirely decided by one's pre-existing opinion about the political actions that each economic policy implies. If you (like me) have already decided that government intervention in the economy is useful to prevent concentration of wealth in the hands of a few and provide support for the most vulnerable, everything Baker and Bernstein say here is going to sound quite convincing. If you've already decided that government intervention in the economy almost always leads to tears, and that a large government with the ability to take economic action is far more dangerous than any of the effects of economic downturns and unemployment, it would surprise me if Baker and Bernstein will change your mind. In other words, I'm skeptical that policy papers like this accomplish much. That said, there are a lot of facts and data here, which at least help ground this ongoing argument in more specifics. The authors show you the math: the evidence for moderate inflation not leading to any serious impact for economies, the very strong correlations between low unemployment rates and rising median wages, the theoretical basis for lower bounds on unemployment rates and our extensive past history of assuming that lower bound is much higher than it actually is, and some pointed comparisons to countries like Germany that have taken many of the specific policy recommendations included here and have a far healthier labor market as a result. All the statistics, charts, and discussion of analysis techniques is fairly dry, but I think the data is compelling. Of course, I was already convinced by earlier reading. There are a few bits here that I hadn't seen before, or at least hadn't internalized. One is a subtle but very important statistical limitation: any uncertainty in measuring the inflation rate will lead to incorrect statistical findings that inflation slows growth. The explanation for this takes several pages and is somewhat technical: the short and somewhat inaccurate version is that growth is measured in inflation-adjusted GDP, so if you get inflation wrong, you magnify the correlation between GDP and inflation. An inaccurately-high measure of inflation rate simultaneously leads to underestimating GDP growth for that country; an inflation rate that's inaccurate on the low side leads to overestimating GDP growth. This is inherent in how this comparison is done, and it's hard to see how to avoid it. It's therefore worth taking any analysis of the growth impact from higher inflation with a grain of salt. (Please note here that we're talking about moderate inflation the typical rates between 1% and 8% that you see in developed economics.) Another bit that was new to me was the analysis of the connection between trade deficits and full employment. I typically dismiss any international trade analysis in macroeconomic policy for the US since international trade is a much smaller part of our economy than most people think it is, and because protectionism has been rightfully discarded as a policy approach. But Baker and Bernstein make an interesting argument here about the effects of a strong currency on increasing unemployment; even with the relatively small amount of trade, reducing the deficit would have a noticeable effect. (Increasing the volume of trade but not changing the balance would not.) The authors certainly don't recommend protectionism; they do recommend being willing to let the value of the dollar drop against other currencies as a good way to reduce the deficit, and to be aware that other central banks have intentional policies of propping up the dollar that we're largely ignoring. They also mention that this is a zero-sum game for the world economy as a whole, although I would have preferred a bit more emphasis on that. You can't get very far via beggar-thy-neighbor economic policy. But it's a good reminder that the obsession in some parts with not "devaluing the currency" is economic nonsense and directly hurts employment. The end of the book discusses a variety of sensible policy recommendations ranging from international currency policy to Germany's work-sharing program where the government subsidies reduction of worker hours the same way that we already subsidize unemployment. They all seemed reasonable to me, although, sadly, I have little faith that the dysfunctional US government will consider any of them seriously, particularly more direct approaches such as government taking on the role of employer of last resort. But they're fun to read about and imagine a US in which the government actually did sensible things like that. Getting Back to Full Employment is pretty dry, and it's hard to shake the feeling that writing things like this is basically pointless, so I'm not sure I can really recommend it. But if you like reading Krugman's columns and are interested in similar material from different people at a longer length, that's basically what this is. Rating: 6 out of 10

[As You Like It, Act III, Scene V] Hey Beautiful I thought of you on the Fourth of July; which does not, in and of itself, distinguish the day from any other since I met you. It was remarkable only in that it was justifiable, given our conversation about fireworks displays. Of course, I'm happy to take the flimsiest of displays as an excuse to mark you. I'm home alone right now, after watching The Bad Seed. Truth be told, the shadows keep spooking me. I can't seem to stop myself from imagining precocious blonde murderers in them. It's a manageable silliness, but made a little less so by the fact that I forgot to lock the door. Less troublesome than the night I spent after Ringu (the original Japanese version of The Ring). I finished watching it in the wee hours of the morning, and I wanted to go to sleep. I was in half a stupor, but the incessant inner critic in me kept imagining all the changes that could have been made to make the movie more truly unsettling until visions of Obake were swimming around me. Ordinarily I doubt I'd be bothered particularly by a 50's classic, but went back up to Boston this afternoon. 's at a conference in Finland, so I invited him down to visit while I have the apartment all to myself. It was strange to have a visitor actually in my home for whom I didn't have to play at being contented. At any rate, being around for three days essentially meant carrying on a three-day-long conversaiton, and the abrupt drop of sociability makes me feel my isolation a little more acutely. We watched The Way We Were together, and agreed that it should be remade with casting that actually works. I hadn't seen it before, and was surprised to find it unusually nuanced and substantial, yet still not good. It was nice to have someone around who would dissect it with me afterward. It's been a while since I actually discussed a film with someone. Partly out of my own fault; I don't always enjoy verbalizing my opinions of movies immediately after watching them if I've found them in the least bit moving. I guess I consider the aftertaste part of the experience. In this case, we both felt the film had missed its emotional mark so it wasn't so much of an issue. On the other hand, I don't find most movies moving. I find them frustratingly flawed, and by the time they end I'm raring to rant about their petty contradictions and failures of logic. I think it might give people the impression that I don't actually make any effort to tease out the messages filmmakers weave into their work. Or maybe I'm just making excuses for having uninteresting friends. Either way, it was pleasant to be in the company of someone eager to tolerate the convolutions of my thought process. On Wednesday night, I have a date to meet up with some former co-workers/friends that I've been passively avoiding for several years now. Every time I fail to carefully manage my visibility, people seem to come flooding back into my life. This time the culprit was a day spent logged into instant messaging without stringent privacy settings. I should feel lucky for that, I suppose. I'm not sure how I actually feel. One of the formers is a woman I was very close to, as far as most of the world her included could discern. The other is a Boston boy I admired for the touch of golden child in the air that hung about him. The main theme of his life was (and I suspect still is) getting to drinks with friends at one of his regular bars at the end of every evening. Which did not at all stop him from being productive, interested in the world, and bright. If he had been a girl I would have been hateful with envy. Instead he's always stood out in my memory as the only person I've had a bit of a crush on despite not finding him particularly intellectually stimulating. A month or so ago he sold his company to google. Now he spends a lot of time out of town giving lectures. I suspect I may be generally happy for him, and I'm not quite sure what to do with that. Thursday I'm leaving for a few days in Denver. I wish I hadn't scheduled it for a time when I could have been the sole occupant of my domicile, but other than that I'm looking forward to it. I've no idea what I'll do there, but at least that means I really am going someplace that wouldn't occur to me outside of a peculiar set of constraints. I think it would be advisable to work out the transportation system before I depart, though. I hope this letter finds you relatively satisfied, at a minimum. I don't actually need to tell you how much I miss talking to you, do I? You're wonderful. Affectionally, as always,

Review: Half Life, by S.L. Huang

Series:	Russell's Attic #2
Publisher:	S.L. Huang
Copyright:	2014
ISBN:	0-9960700-5-2
Format:	Kindle
Pages:	314

This is a sequel to Zero Sum Game and the second book about Cas Russell, a mercenary superhero (in a world without the concept of superheroes) with preternatural ability to analyze anything about her surroundings with mathematics. While it reuses some personal relationships from the first book and makes a few references to the villains, it's a disconnected story. It would be possible to start here if you wanted to. Cas is now in the strange and unexpected situation of having friends, and they're starting to complicate her life. First, Arthur has managed to trigger some unexpected storehouse of morals and gotten her to try to stop killing people on jobs. That conscience may have something to do with her willingness to take a job from an apparently crazy man who claims a corporation has stolen his daughter, a daughter who appears nowhere in any official records. And when her other friend, Checker, gets in trouble with the mob, Cas tries to protect him in her own inimitable way, which poses a serious risk of shortening her lifespan. Even more than the first book, the story in Half Life is a mix of the slightly ridiculous world of superheroes with gritty (and bloody) danger. It featuring hit men, armed guards, lots of guns, and quite a lot of physical injury and blood. A nasty corporation that's obviously hiding serious secrets shares pages with the matriarch of a mob family who considers Checker sleeping with her daughter to be an abuse of her honor. The story eventually escalates into more outlandish bits of technology, an uncanny little girl, and a plot that would feel at home in a Batman comic. I like books that don't take themselves too seriously, but the contrast between the brutal treatment Cas struggles through and the outrageous mad scientist villain provokes a bit of cognitive whiplash. That said, the villains of Half Life are neither as freakish nor as disturbing as those in Zero Sum Game, which I appreciated. Huang packs in several plot twists, some inobvious decisions and disagreements between Russell and her friends about appropriate strategy, and Cas's discovery that there are certain things she cares very strongly about other than money and having jobs. Cas goes from a barely moral, very dark hero in the first book to something closer to a very grumbly chaotic good who insists she's not as good as she actually is. It's a standard character type, but Huang does a good job with it. Huang also adds a couple of supporting cast members in this book that I hope will stick around. Pilar starts as a receptionist at one of the companies Cas breaks into, and at first seems like she might be comic relief. But she ends up being considerably more competent than she first appears (or that she seems to realize); by the end of the book, I had a lot of respect for her. And Miri makes only a few appearances, but her unflappable attitude is a delight. I hope to see more of her. The biggest drawback to this book for me is that Cas gets hurt a lot. At times, the story falls into one of the patterns of urban fantasy: the protagonist gets repeatedly beaten up and abused until they figure out what's going on, and spends most of the story up against impossible odds and feeling helpless. That's not a plot pattern I'm fond of. I don't enjoy reading about physical pain, and I had trouble at some points in the story with the constant feeling of dread. Parts of the book I read in short bursts, putting it aside to look at something else. But the sense of dread falls off towards the end of the book, as Cas figures out what's actually going on, and none of it is as horrible as it felt it could be. If you have a similar problem with some urban fantasy tropes, I think it's safe to stick with the story. This was a fun story, but it doesn't develop much in the way of deeper themes in the series. There's essentially no Rio, no further discoveries about the villains of the first book, and no further details on what makes Cas tick or why she seems to be the only, or at least one of the few, super-powered people in this world. The advance publicity for the third book seems to indicate that's coming next. I'm curious enough now that I'll keep reading this series. Recommended if you liked the first book. Half Life is very similar, but I think slightly better. Followed by Root of Unity. Rating: 7 out of 10

Weblate 2.4 has been released today. It comes with extended support for various file formats, extended hook scripts, better keyboard shortcuts and dozen of bug fixes. Full list of changes for 2.4:

• Improved support for PHP files.
• Ability to add ACL to anonymous user.
• Improved configurability of import_project command.
• Added CSV dump of history.
• Avoid copy/paste errors with whitespace chars.
• Added support for Bitbucket webhooks.
• Tigher control on fuzzy strings on translation upload.
• Several URLs have changed, you might have to update your bookmarks.
• Hook scripts are executed with VCS root as current directory.
• Hook scripts are executed with environment variables descriping current component.
• Add management command to optimize fulltext index.
• Added support for error reporting to Rollbar.
• Projects now can have multiple owners.
• Project owners can manage themselves.
• Added support for javascript-format used in Gettext PO.
• Support for adding new translations in XLIFF.
• Improved file format autodetection.
• Extended keyboard shortcuts.
• Improved dictionary matching for several languages.
• Improved layout of most of pages.
• Support for adding words to dictionary while translating.
• Added support for filtering languages to be managed by Weblate.
• Added support for translating and importing CSV files.
• Rewritten handling of static files.
• Direct login/registration links to third party service if that's the only one.
• Commit pending changes on account removal.
• Add management command to change site name.
• Add option to confiugure default committer.
• Add hook after adding new translation.
• Add option to specify multiple files to add to commit.

If you are upgrading from older version, please follow our upgrading instructions. You can find more information about Weblate on http://weblate.org, the code is hosted on Github. If you are curious how it looks, you can try it out on demo server. You can login there with demo account using demo password or register your own user. Weblate is also being used https://hosted.weblate.org/ as official translating service for phpMyAdmin, Gammu, Weblate itself and other projects. If you are free software project which would like to use Weblate, I'm happy to help you with set up or even host Weblate for you. Further development of Weblate would not be possible without people providing donations, thanks to everybody who have helped so far! PS: The roadmap for next release is just being prepared, you can influence this by expressing support for individual issues either by comments or by providing bounty for them.

Filed under: English phpMyAdmin SUSE Weblate 0 comments

This year, Sarah and I spent two weeks off the coast of Dubrovnik, on Kolo ep island. We'd never been to Croatia before, and I was a little nervous that if there wasn't much to do on the island, we wouldn't be able to get elsewhere particularly easily. I needn't have worried: We thoroughly enjoyed our stay. It might even be my favourite holiday so far. We did travel around a bit: twice to Dubrovnik's old town and once to a botanical gardens in Trsteno but there was also loads to see on the island itself. One of our favourite trips was simply to a cave on the opposite side of the island known as a "blue cave" because you looked like a Smurf on the inside. We had to jump into the sea from the boat and swim into and out of the cave before continuing on our trip. Simply puttering about on the boat, either around the island or to Trsteno was a great experience in itself. Our guide Sammi was very friendly, the weather was great and swimming around or just enjoying the sun on the back of the boat was enough for me to want to check property prices out there. On Kolo ep island is a little restaurant called Villa Ruza. We managed to eat there twice during our stay. I think it is considered to be one of the top ten restaurants in Croatia. It's one of the best places I've ever eaten in my life. In terms of price, it was about half that of restaurants in Dubrovnik itself. Dubrovnik itself was, quite predictably, much busier than Kolo ep. It is a stunningly attractive old town. On our second visit we took a tour. There are a variety of different themed tours that you can take, including Game Of Thrones sight-seeing tours, and there were Game Of Thrones tat shops all over the place. We opted for A Story About The War. One thing we love to do when visiting foreign places is to get an idea of what life is like for people there, and this war was not all that long ago - I can remember the news coverage from the time. We were the only two people on that particular tour, so we had a fairly tailored experience. I wish I could remember our guide's name. She was the same age as us and grew up as a child in the city when it was under siege. Her personal story included details about where her family stayed; what life was like for kids growing up at the time; how people got supplies; which areas were badly affected and much more. It was a very heartfelt tour and gave us an intimate and personal portrait of what life was like for people there at a time that most tour operators tend to prefer to ignore. This was exactly what we were looking for. Sarah and I were both a little teary at the end! We tried to do things a little different on this holiday. Normally we keep ourselves to ourselves and don't socialise much with other guests. We also rarely do trips and excursions, preferring to sort things out for ourselves. This time we made an effort to be more sociable and I'm glad we did because we met some really nice people. The trips we did were great fun and on the last day I blew through most of the rest of our currency by hiring a jet ski for half an hour. Those things are FUN. Top speed on the one I was using was 57 land mph. Every muscle in my body was screaming for a few days afterwards! Often on a two-week holiday we reach a point around 10 days where we've pretty much had enough. This time around I could have stayed for twice as long. This was the first proper test of my new camera and I've uploaded a set of photographs from our holiday to a Flickr gallery.

Review: Magic's Promise, by Mercedes Lackey

Series:	Last Herald Mage #2
Publisher:	DAW
Copyright:	January 1990
ISBN:	0-88677-401-2
Format:	Mass market
Pages:	320

Magic's Promise is the second book of the Last Herald Mage trilogy and a sequel to Magic's Pawn. As tempting as it is to skip the first book, which isn't very good, I think you'd miss a lot of the emotional dynamics between Vanyel and his family if you didn't read it. Magic's Promise opens years after the end of Magic's Pawn. Vanyel has become the most powerful Herald-mage of the kingdom, which is lucky for the kingdom because it's beset on all sides by magical attack. Heralds are being killed, countries on the border are looking for opportunities to spring, and Vanyel is being run ragged. Ragged enough that he's worried he's going to hurt someone by mistake when surprised. It's time for a desperately-needed vacation. Unfortunately for his ability to relax, that vacation means going home to visit his parents, who have never understood him and who disapprove strongly of his sexuality. (Not that he's actually had a lover in years.) It also means being in the same household as the armsmaster who broke his wrist as a child, and his father's deeply disapproving priest. And the border near his parents' lands may be heating up as well. Magic's Promise is the book where this trilogy hits its stride. After the events of the previous book, Vanyel is ridiculously overpowered and will be for the rest of the trilogy, but the problems in this book aren't the sort that raw power can fix. (That's a balance Lackey handles well in general.) There are a few places where Vanyel can simply overpower his problems, but the heart of the plot is a mystery that requires analysis, investigation, and a bit of undercover snooping. I enjoyed the defense of the kingdom plot (more than I had remembered, in fact), but the heart of this book is Vanyel and his family coming to terms with each other. Vanyel is a lot older and more confident than he was in the first book, and his service to the kingdom forces some grudging respect. But the way that grudging respect turns into real affection over the course of this book is a delight to read. This degree of reconciliation is wish-fulfillment most of the Valdemar series is heavy on wish-fulfillment but it's the sort of wish-fulfillment that matches the way that you wish the world would work. People figure out that they've been ignorant and cruel and actually change, and Vanyel learns some important lessons about giving people room to change. I particularly liked that the growth of respect wasn't one-sided. Most of the movement comes (and has to come) from Vanyel's family, but Vanyel gains some new-found appreciation and empathy for some strengths that he'd previously been blind to. Lackey's writing is still not the best here. There's something a bit awkward about the dialogue patterns in places, one gets a bit tired of the repetitive narrative focus on Vanyel's exhaustion, and the sentence-level construction of the story is more workable than delightful. You have to be invested in the characters; the beauty of the writing itself isn't going to win you over. As with a lot of Lackey's writing, I think your enjoyment will depend greatly on whether she happens to hit your emotional buttons. But the story she tells here, of people finding the inner goodness in each other and healing over past wounds, is one that I very much enjoy reading. I think this is the third time I read this book, and it's the first of the Valdemar series in this re-read that held up to my memory. So far, it's the best of the series. Followed by Magic's Price. Rating: 8 out of 10

Two helpful CMS commands to know if the users on the z/VM host you connect to are managed using DIRMAINT:

• DIRMAINT PW: This will ask you for your current password and then for the new one. This way you can change your own user password instead of having to ask the administrator for it.
• DIRMAINT REVIEW: If you want to see the directory entry for your user (i.e. the configuration of your VM), you can issue this command. It will put the directory onto the card stack, from which you can retrieve it onto your A disk using RETRIEVE <number> <USERNAME> DIRECT A. The number is listed after RDR FILE in CP's output.

Review: Magic's Pawn, by Mercedes Lackey

Series:	Last Herald Mage #1
Publisher:	DAW
Copyright:	June 1989
ISBN:	0-88677-352-0
Format:	Mass market
Pages:	349

Continuing my (very slow) re-read of Mercedes Lackey's Valdemar series. I've read all these books before (this series several times, in fact), but long before I started writing reviews. Vanyel is a legendary hero by the time of Talia (the hero of the first Valdemar series, starting with Arrows of the Queen). Talia was reading stories about him at the start of her story: the mage Herald who defended Valdemar against its enemies in the distant past. This is the first book of the trilogy that tells his story, starting (as Lackey's books often do) from rather inauspicious beginnings. Vanyel is the son of a border lord, and about as poorly suited for it as possible. He's small, pretty, entirely uninterested in the hammer-and-tongs sword fighting the arms master wants to teach him, and also gay, not that he has any idea that's even something that exists and has a name. His only ally was his sister, who is now off serving in Valdemar's military. Most of his life is spent hiding, feeling utterly lost and out of place, and wishing he could be a Bard. This is a Valdemar story, so if you're familiar with the series, you know what's coming next. What might come as a surprise is that "next" is quite some time into the story. Vanyel does not get rescued from his situation by a Companion. Instead, his father decides to exile him to the capital under the care of his aunt, who he's only met once and who didn't think highly of him. He expects to be even more miserable, and shuts emotionally down in anticipation. This is one of those books that I remembered as being better than it actually was, and one of the reasons why I enjoyed it less than I expected is that far too much of this book is devoted to describing Vanyel's mental state. This usually involves various elaborate emo analogies (which can be a failing of this series in general), and it's quite hard to maintain sympathy for Vanyel. Lackey gets us to feel for him at the start of the book, when he's really in a bad situation. But once he gets to the capital, he's his own worst enemy, and it's hard to avoid the desire to shake him. I also didn't remember just how much I disliked Tylendel. I'm sure it will come as a surprise to no one that Vanyel eventually meets someone who draws him out of his shell and gives him a reason to want to live. Unfortunately, that person, despite a positive surface impression, is self-obsessed, unstable, and not above manipulating Vanyel into actions that are so obviously catastrophic that it makes one want to yell at the book. I disliked this part of the book so much that even a Companion's choosing was overshadowed. The book does get a bit better after that truly awful middle, but it never hits the emotional stride that other Valdemar books hit. Lackey does introduce the Tayledras, which will be hugely important in later books in this series (and who are some of my favorite characters), but there too I prefer their later appearances. Vanyel's inability to see a good thing when it hits him in the face, punctuated by being occasionally cruel to the people who try to help him, makes it quite hard to enjoy his slow path to becoming a better person. I remember really liking this trilogy, so I think it gets better. But I also remembered liking Vanyel's claiming, and it didn't do much for me on a re-read. I can only recommend this one as a necessary preface to the later books in the trilogy, and expect to need a high tolerance for constant woe-is-me despair. Followed by Magic's Promise. Rating: 5 out of 10

Finally I found the time and peace to watch one of the strangest movies that I have ever seen, Werner Herzog s (Offical Site, Wikipedia) Fata Morgana (Wikipedia, IMDb). Footage prepared for a SF movie that never realized, converted into an impressionistic allegory and movie full of phantasms.
Fata Morgana is a movie that escapes every description. Having read several critics voices, as well as Herzog s comments in the excellent interview/(auto)biography book Werner Herzog A guide for the perplexed, I was eager to see this old and special movie. Having laid my hand on a collection of Werner Herzog s old movies recently, I prepared some good Japanese sake, and was ready to enjoy the move. The initial sequence of airplanes landing on a very hot day, again and again, sets the stage for a series of dream-like sequences in this movie. Divided into three parts, the movie tells its story only by visual impressions and the reading of the Mayan creation myth Popol Vuh, at times intermixed with some Leonard Cohen songs. Part One Creation introduces the desert as the origin of the world, accompanied by the initial creation myth before humans were formed. Part 2 Paradise is when humans enter into the desert. Full of ramshackle houses and rotten buildings, the contrast of the spoken words and imaginary cannot be more stunning. The final part 3 The Golden Age is full of absurdities and strange appearances, not surprisingly also most humans appear here. Watching this movie is more a visual experience for me than about seeing a story line. While there are many ways to interpret the relation between the Popol Vuh and the movie sequences, for me it is more a visual experiment that tries in some sense to hypnotize the audience. For those who love strange movies, an absolute must. For all others probably a torture.

A few days ago, the French equivalent of Hacker News, called "Le Journal du Hacker", interviewed me about my work on OpenStack, my job at Red Hat and my self-published book The Hacker's Guide to Python. I've spent some time translating it into English so you can read it if you don't understand French! I hope you'll enjoy it.

Hi Julien, and thanks for participating in this interview for the Journal du Hacker. For our readers who don't know you, can you introduce you briefly?

You're welcome! My name is Julien, I'm 31 years old, and I live in Paris. I now have been developing free software for around fifteen years. I had the pleasure to work (among other things) on Debian, Emacs and awesome these last years, and more recently on OpenStack. Since a few months now, I work at Red Hat, as a Principal Software Engineer on OpenStack. I am in charge of doing upstream development for that cloud-computing platform, mainly around the Ceilometer, Aodh and Gnocchi projects.

Being myself a system architect, I follow your work in OpenStack since a while. It's uncommon to have the point of view of someone as implied as you are. Can you give us a summary of the state of the project, and then detail your activities in this project?

The OpenStack project has grown and changed a lot since I started 4 years ago. It started as a few projects providing the basics, like Nova (compute), Swift (object storage), Cinder (volume), Keystone (identity) or even Neutron (network) who are basis for a cloud-computing platform, and finally became composed of a lot more projects. For a while, the inclusion of projects was the subject of a strict review from the technical committee. But since a few months, the rules have been relaxed, and we see a lot more projects connected to cloud-computing joining us. As far as I'm concerned, I've started with a few others people the Ceilometer project in 2012, devoted to handling metrics of OpenStack platforms. Our goal is to be able to collect all the metrics and record them to analyze them later. We also have a module providing the ability to trigger actions on threshold crossing (alarm). The project grew in a monolithic way, and in a linear way for the number of contributors, during the first two years. I was the PTL (Project Technical Leader) for a year. This leader position asks for a lot of time for bureaucratic things and people management, so I decided to leave my spot in order to be able to spend more time solving the technical challenges that Ceilometer offered. I've started the Gnocchi project in 2014. The first stable version (1.0.0) was released a few months ago. It's a timeseries database offering a REST API and a strong ability to scale. It was a necessary development to solve the problems tied to the large amount of metrics created by a cloud-computing platform, where tens of thousands of virtual machines have to be metered as often as possible. This project works as a standalone deployment or with the rest of OpenStack. More recently, I've started Aodh, the result of moving out the code and features of Ceilometer related to threshold action triggering (alarming). That's the logical suite to what we started with Gnocchi. It means Ceilometer is to be split into independent modules that can work together with or without OpenStack. It seems to me that the features provided by Ceilometer, Aodh and Gnocchi can also be interesting for operators running more classical infrastructures. That's why I've pushed the projects into that direction, and also to have a more service-oriented architecture (SOA)

I'd like to stop for a moment on Ceilometer. I think that this solution was very expected, especially by the cloud-computing providers using OpenStack for billing resources sold to their customers. I remember reading a blog post where you were talking about the high-speed construction of this brick, and features that were not supposed to be there. Nowadays, with Gnocchi and Aodh, what is the quality of the brick Ceilometer and the programs it relies on?

Indeed, one of the first use-case for Ceilometer was tied to the ability to get metrics to feed a billing tool. That's now a reached goal since we have billing tools for OpenStack using Ceilometer, such as CloudKitty. However, other use-cases appeared rapidly, such as the ability to trigger alarms. This feature was necessary, for example, to implement the auto-scaling feature that Heat needed. At the time, for technical and political reasons, it was not possible to implement this feature in a new project, and the functionality ended up in Ceilometer, since it was using the metrics collected and stored by Ceilometer itself. Though, like I said, this feature is now in its own project, Aodh. The alarm feature is used since a few cycles in production, and the Aodh project brings new features on the table. It allows to trigger threshold actions and is one of the few solutions able to work at high scale with several thousands of alarms. It's impossible to make Nagios run with millions of instances to fetch metrics and triggers alarms. Ceilometer and Aodh can do that easily on a few tens of nodes automatically. On the other side, Ceilometer has been for a long time painted as slow and complicated to use, because its metrics storage system was by default using MongoDB. Clearly, the data structure model picked was not optimal for what the users were doing with the data. That's why I started Gnocchi last year, which is perfectly designed for this use case. It allows linear access time to metrics (O(1) complexity) and fast access time to the resources data via an index. Today, with 3 projects having their own perimeter of features defined and which can work together Ceilometer, Aodh and Gnocchi finally erased the biggest problems and defects of the initial project.

To end with OpenStack, one last question. You're a Python developer for a long time and a fervent user of software testing and test-driven development. Several of your blogs posts point how important their usage are. Can you tell us more about the usage of tests in OpenStack, and the test prerequisites to contribute to OpenStack?

I don't know any project that is as tested on every layer as OpenStack is. At the start of the project, there was a vague test coverage, made of a few unit tests. For each release, a bunch of new features were provided, and you had to keep your fingers crossed to have them working. That's already almost unacceptable. But the big issue was that there was also a lot of regressions, et things that were working were not anymore. It was often corner cases that developers forgot about that stopped working. Then the project decided to change its policy and started to refuse all patches new features or bug fix that would not implement a minimal set of unit tests, proving the patch would work. Quickly, regressions were history, and the number of bugs largely reduced months after months. Then came the functional tests, with the Tempest project, which runs a test battery on a complete OpenStack deployment. OpenStack now possesses a complete test infrastructure, with operators hired full-time to maintain them. The developers have to write the test, and the operators maintain an architecture based on Gerrit, Zuul, and Jenkins, which runs the test battery of each project for each patch sent. Indeed, for each version of a patch sent, a full OpenStack is deployed into a virtual machine, and a battery of thousands of unit and functional tests is run to check that no regressions are possible. To contribute to OpenStack, you need to know how to write a unit test the policy on functional tests is laxer. The tools used are standard Python tools, unittest for the framework and tox to run a virtual environment (venv) and run them. It's also possible to use DevStack to deploy an OpenStack platform on a virtual machine and run functional tests. However, since the project infrastructure also do that when a patch is submitted, it's not mandatory to do that yourself locally.

The tools and tests you write for OpenStack are written in Python, a language which is very popular today. You seem to like it more than you have to, since you wrote a book about it, The Hacker's Guide to Python, that I really enjoyed. Can you explain what brought you to Python, the main strong points you attribute to this language (quickly) and how you went from developer to author?

I stumbled upon Python by chance, around 2005. I don't remember how I hear about it, but I bought a first book to discover it and started toying with that language. At that time, I didn't find any project to contribute to or to start. My first project with Python was rebuildd for Debian in 2007, a bit later. I like Python for its simplicity, its object orientation rather clean, its easiness to be deployed and its rich open source ecosystem. Once you get the basics, it's very easy to evolve and to use it for anything, because the ecosystem makes it easy to find libraries to solve any kind of problem. I became an author by chance, writing blog posts from time to time about Python. I finally realized that after a few years studying Python internals (CPython), I learned a lot of things. While writing a post about the differences between method types in Python which is still one of the most read post on my blog I realized that a lot of things that seemed obvious to me where not for other developers. I wrote that initial post after thousands of hours spent doing code reviews on OpenStack. I, therefore, decided to note all the developers pain points and to write a book about that. A compilation of what years of experience taught me and taught to the other developers I decided to interview in the book.

I've been very interested by the publication of your book, for the subject itself, but also the process you chose. You self-published the book, which seems very relevant nowadays. Is that a choice from the start? Did you look for an editor? Can you tell use more about that?

I've been lucky to find out about others self-published authors, such as Nathan Barry who even wrote a book on that subject, called Authority. That's what convinced me it was possible and gave me hints for that project. I've started to write in August 2013, and I ran the firs interviews with other developers at that time. I started to write the table of contents and then filled the pages with what I knew and what I wanted to share. I manage to finish the book around January 2014. The proof-reading took more time than I expected, so the book was only released in March 2014. I wrote a complete report on that on my blog, where I explain the full process in detail, from writing to launching. I did not look for editors though I've been proposed some. The idea of self-publishing really convince me, so I decided to go on my own, and I have no regret. It's true that you have to wear two hats at the same time and handle a lot more things, but with a minimal audience and some help from the Internet, anything's possible! I've been reached by two editors since then, a Chinese and Korean one. I gave them rights to translate and publish the books in their countries, so you can buy the Chinese and Korean version of the first edition of the book out there. Seeing how successful it was, I decided to launch a second edition in Mai 2015, and it's likely that a third edition will be released in 2016.

Nowadays, you work for Red Hat, a company that represents the success of using Free Software as a commercial business model. This company fascinates a lot in our community. What can you say about your employer from your point of view?

It only has been a year since I joined Red Hat (when they bought eNovance), so my experience is quite recent. Though, Red Hat is really a special company on every level. It's hard to see from the outside how open it is, and how it works. It's really close to and it really looks like an open source project. For more details, you should read The Open Organization, a book wrote by Jim Whitehurst (CEO of Red Hat), which he just published. It describes perfectly how Red Hat works. To summarize, meritocracy and the lack of organization in silos is what makes Red Hat a strong organization and puts them as one of the most innovative company. In the end, I'm lucky enough to be autonomous for the project I work on with my team around OpenStack, and I can spend 100% working upstream and enhance the Python ecosystem.

I watched PIXELS in a theater. It subjects about video games, mostly retro 80 s arcade games. I love video games from childhood, my first game played would be Taito s Space Invaders, I was the 4 or 5 yeas old time. It had bring me to the computer world. Fortunately I am working at Akihabara area, so I can play the video games in the movie like Pac-man, Glaga, Cemtipede, Donkey Kong and so on in two gamecenters, Natsuge Museum and Hey (Hirose Entertainment Yard . Natsuge Museum is under private management so it closes week days. They focused to old games between 70 th to 90 th. Hey is a franchised shop ownd by TAITO. They covered almost video games except medal games. You can play old games like Paper-boy, The Tower of Druaga, and newest games like Left4Dead arcade. They correct many titles of the games in the movie, and be playable. They are my recommended place in Akihaba, if you like video games.