Why did you start programming

2013-11-22  |   |  real life  

While discussing with a mom whose boy wants a computer for Christmas, the said "I suppose he wants to play games, what for otherwise?". To this I obviously replied "Programming!". The usual question popped up:

Why did you start (learning) programming?

I posed longer than usual this time along. This is not as trivial as it sounds.

Non programmers truly don't understand why someone would spend hours deep into this arcane thing. They would expect to spend time away from that damn machine or at least play games on it ; this could be considered fun at least, right?


Well, it's fairly complex but there is almost always a combination of the following:

  • it was the only way to achieve A (wrote my own game because I could not get ones off the shelves)
  • make this machine do what I want: empowerment and control in a deterministic world.
    Programmers tend to be slightly autistic when in the zone: determinism is really reassuring
  • fiddling with things. When you break dad's computer, you better have to find a way to fix it before he finds out. That required technical deep dives under adrenaline.

I asked the question (why did you start programming) to the twitter-sphere. Here is the compilation in 140 characters or less.

Raw data and other stories

for me it was ~10, staring at this C:> and knowing that I could control that beast to do what I wanted. - Emmanuel Bernard

Don't take it that I am a person that enjoys control over things. It was more having the power to do what I could imagine.

to have fun with my computer and display a rotating cube :) when I was 14 - Gerben Castel

Because it was the easiest way to render mathematics concrete - Fabrice Croiseaux

Apologies Fabrice but this on ought to be the weirdest ;)

I had to get a winmoden working with Linux in 96 - Fernando Meyer

I wanted to do like my older brother who could tell his programmable calculator what to do, and it would obey his orders! - Guillaume Laforge

Now Guillaume definitely is after power ;)

I was 8, I had a Commodore 64, and I wanted to know how I could tell it what to do. - Laurent Pireyn

for me it was seeing games on a C64 and thinking: I wanna make something like that! - Marvin

un pote qui m'a montré visual basic quand j'étais au lycée... le côté créatif et ludique m'a donné envie d'essayer - Loïc Descotte

got an old Mo5 from my cousins around 8 and had to learn how to use it to play games recorded on tapes... - benzonico

I got fascinated by those strange sentences on my VIC20 manual that could make my VIC20 display beautiful things on TV :) - Fabio Mancinelli

i was so excited to write my surname on the screen of our #zx81 - asicfr

11 in 1982, ZX81, Basic. Amazed to see a machine reproduce what I had written : a program. - Jean-Baptiste Briaud

In ~1980, Video games and computers were everywhere in Tokyo. First step was to play with, then to understand them. - Sébastien Douche

At 10, I was into drawing, he was into game programming. He's an architect (building), I'm a programmer. #BrotherAndSister - Corinne

Knowledge transfer at play ;)

My father brought a ZX81 in my lost village. - Didier Girard

Nothing else to do I guess.

As a kid I was not allowed to have a gaming console, only a C64. Had to build games myself. - Olivier Hubaut

age 9, tried format A: w/ ASM from P. Norton book, ended up fmting C:, my 1st app,1st OS reinstall & freaked out dad :) - Jo Voordeckers

I did that one too. I was annoyed by the . and .. in each directory so I deleted them! I deleted autoexec.bat and config.sys and ended up reinstalling the OS. Fiddling with things is core to programmer psyche.

The need to automate things. Write once, Run many times ! - Laurent

A lazy guy right there! Another trait of programmers.

Because computer didn't blame me when I failed vs sport/friends being a shy child. + Proud by "I did it myself" - Nicolas De loof

Despite what others think, a computer is a very predictable environment and is very reassuring for all these mildly autistic programmer minds.

@julienkauffmann qui me fait découvrir Delphi et comment changer la couleur du fond en cliquant sur un bouton. - Faulomi

I was ~11 and L'Ordinateur Individuel had a paper computer in it, with working memory registers and operators :) - David Dossot

Now that's hardcore.

as a child, it was amazing. "Look what I can do!". Getting your hands dirty. - Cédric Champeau

Craftsman spirit (power of creation). It starts with #Lego and continues with programming ;) - Daniel PETISME

code my own video game on my Alice computer. And feel powerful.... - Da Follower

Never touched a computer before entering CS. Seemed like perfect mix hard/applied science + creativity. Was fucking right! - Cyril Lacôte

At 7, my father bought a ZX81. It seemed funny, I learned "Print" ! 32 years after, still coding :) - Laurent CARON

read an article / subliminal images. Wrote a zx spectrum program to influence myself to work more in school:-)
it was in basic. Never got enough fps to make the message subliminal, so it failed... or not:-)
- chanezon

I guess that's another one in the lazy category. Pretty clever though :)

wanted to program my own adventure game on the ZX Spectrum, like The Hobbit - never got around to it though :-) - Thomas Conté

because you create things out of thin air. - Jean-Laurent Morlhon

Hum, I'm sure that's not what you thought when you started as a kid.

C++ when i was 14 to create modules for D&D neverwinter nights :) - Vivian Pennel

A man with a goal.

around ten, cpc464 as Christmas gift. I had to understand how games launched with load and run commands - Mat

i was 8 years old, my Father got a CPC464, i wanted Pac Man, my Father gave me a Basic book and told me "do it yourself" - Grégory M.

A dad with foresight. Though tough on his kid.

10 y.o.: 1st family computer. 11 y.o.: Word crash, lose 1h of homework. Next day: buy Linux CD, install. Then Bash, Perl... - Pierre Chapuis

Now imagine Mom and Dad's face when they tried to launch Word the next day :)

coder les musiques des séries tv en basic sur amstrad 6128 il y a ... 25 ans... k2000 supercopter & co #nostalgie - Alfred Almendra

Electronic music.

be able to hack into systems like the boy in "wargames" - Laurent Bristiel

Movies are bad for you kids, you have been warned! Lucky you did not for nuclear strike hacking.

at 6 wanted to help Man to land again on the moon, I thought the computer were the tool that build rockets like movies - Guillaume Wallet

Let me tell you, these moon guys knew their logarithmic tables by heart.

And you?

What's your story? Why did you start programming?

Notes sur les garbage collectors de la JVM

2013-09-22  |   |  java   francais  

Lors d'une discussion sur les différents garbage collectors disponibles sur la JVM, Rémi Forax est sorti de sa tanière et nous a fait un résumé que je trouve intéressant.

Un peu de contexte, on parlait des différents garbages collectors:

  • CMS (Concurrent Mark Sweep): implémentation "classique" dans la JVM HotSpot
  • G1: nouvelle implémentation dans la JVM HotSpot qui doit remplacer à terme CMS
  • C4: Azul's "pauseless" garbage collector

On parlait notamment de l'impact du temps pendant lequel les garbages collectors arrêtent le monde (stop the world).

Je laisse Rémi parler (édition mineure de ses propos et emphases personnelle):

Un GC ça marche en deux grosses phases, le marquage et la réclamation de la mémoire des objets non marqués. Pour qu'un GC soit rapide et efficace il faut essayer de faire les deux phases en même temps que le programme Java tourne. Autant pour le marquage on peut faire les choses pendant que le programme tourne autant pour la partie collection c'est plus délicat.

Il y a deux principaux algorithmes de collection,

  • le sweep où on alloue et désalloue comme malloc et free, dans ce cas les objets ne bougent pas en mémoire et on peut se retrouver avec du gruyère en mémoire
  • ou le compact qui consiste à recopier les objets vivants (les marqués) vers une autre zone.

L'algo de compact est meilleur mais:

  • pour bien marcher il faudrait 2 fois plus de mémoire que nécessaire, comme cela on a toujours la place de copier les objets d'un endroit à un autre.
  • comme on bouge les objets en mémoire, le programme Java ne peut pas tourner en même temps car il faut mettre à jour toutes les références de tous les objets entre leur ancienne adresse et leur nouvelle adresse.

De plus, réclamer la mémoire de tous le tas est lent si il est gros, donc on découpe le tas en zone, et on essaye de faire l'algo de GC sur peu de zones à la fois. Pour cela, il faut que l'on sache si une zone possède des pointeurs vers les autres zones (et à peu près où sont situés les référence). Dans ce cas le GC est incrémental et on utilise le mécanisme de protection de page pour tracker les références inter-zones.


Pour CMS, le tas est composé de plusieurs zones ordonnées, on fait des compacts pour passer les objets d'une zone à une autre et la dernière zone (assez grosse) ne fait pas de compact mais un sweep.
Cette organisation permet de faire un tracking des objets inter-zone plus simple, on regarde uniquement les pointeurs entre les zones les plus grandes vers les zones les plus petites donc on a pas besoin de coder vers quelle zone pointent les références.


Pour G1, on track les références inter-zones complets, donc toutes les zones font des compacts mais le mécanisme de tracking est plus compliqué. L'idée de G1 est que l'on indique le temps de collection maximum et qu'il adapte le nombre de zone qu'il faudra collecter en fonction. Donc on a des pause, mais si tous ce passe bien, leur durée est bornée.


Pour C4, l'idée est de faire la phase de collection de façon lazy, comme un compact normal, on bouge les objets en mémoire mais on ne ré-écrit pas les adresses, les références restent avec l'ancienne adresse mais on protège les pages contenant les anciens objet. Comme cela lorsque le programme cherche à accéder à un objet, si il possède une référence sur l'ancienne adresse, le mécanisme de protection mémoire émet un page fault. Et là il y a une astuce, lors d'un page fault, on sait à quelle adresse on a voulu lire et aussi quel instruction a merdé. Donc si lors de la génération du code assembleur on est capable pour chaque instruction qui peut générer un page fault de dire de quel champ de quel objet il s'agit, on peut mettre à jour la référence dans l'objet donc on aura pas de page fault au prochain accès de ce champ car la référence stockée dans le champ sera mise à jour.

Comme on utilise le mécanisme de protection mémoire de façon importante, l'implantation Linux de base n'est pas assez efficace, donc il faut patcher ton Linux. Le patch n'est pas petit car pour que ça dépote, la structure de données derrière est très spécifique et assez grosse ce qui fait que le patch a peut de chance d'intégrer un jour le trunk de linux.

Donc on a pas de pause comme pour CMS ou G1. En fait, il reste quelques pauses car il faut quand même faire un peu de synchro entre les différentes phases de l'algo de GC, mais lors de l'exécution du code on paye le surcout de mise à jour des références au fur et à mesure. De plus, il faut garder pas mal d'information et au niveau du code généré et au niveau de chaque zone pour être capable de faire l'association entre l'ancienne adresse et la nouvelle. Donc on a pas de pause, mais on a un overhead plus important qu'avec CMS ou G1 (G1 a déjà un overhead plus important que CMS à cause du tracking des références inter-zones).


En conclusion, pas de solution miracle, le GC à un overhead la question est quand veut-on le payer.

Change the Apple TV WiFi settings without remote

2013-08-15  |   |  apple  

You have your Apple TV but no remote and need to change the WiFi settings? Read on.

You're on vacations and as a good geek, you're fully autonomous and packed:

  • your Apple TV
  • a router
  • an HDMI cable
  • your iPhone
  • a couple of ethernet cables

You forgot your Apple TV remote chiefly because you always use the iOS Remote App at home.

Now you try and change the Apple TV WiFi settings and oh horror, either you plug the Apple TV through the ethernet cable and you can use the iOS Remote App, or you unplug the cable to set the WiFi but the Remote App no longer sees the Apple TV. You are stuck!

My friends, there is a way out of catch 22 hell.

  1. Find a regular TV remote.
  2. Plug the ethernet cable to the Apple TV.
  3. With the iOS Remote App go to Settings -> Geenral -> Remotes,
  4. Select Learn Remote and follow the easy steps to teach to Apple TV your TV remote.
  5. Once done, unplug the ethernet cable and set the WiFi under General -> Network -> Wi-FI.

Your vacations are saved. No need to thank me ;)

One line per idea

2013-08-08  |   |  writing  

Now that most of my writing is done in a markup language like Markdown or Asciidoc, and now that I do version my writing in an SCM (Git to be specific), I have been wondering about how to spit text. I have considered 80 characters per line (plus auto wrapping) or one sentence per line.

Line wrapping

Automatic line wrapping is aesthetically pleasant but if I change the very beginning of a paragraph, my whole paragraph is marked as changed in diff.

 The problem with the former is that if I
-change the very beginning of a paragraph,
-my whole paragraph is marked as changed
-in diff. The problem with the latter is
-that sentences tend to be quite long and
-thus wrap and changes are hard to track
-to even though it is easier than with the
-former approach.
+happen to change the very beginning of a
+paragraph, my whole paragraph is marked
+as changed in diff. The problem with the
+latter is that sentences tend to be quite
+long and thus wrap and changes are hard
+to track even though it is easier than
+with the former approach.

One line per sentence

One sentence per line partly solves the diff problem but sentences tend to be quite long (and thus wrap) and changes are not fully obvious to track even though it is easier than with the line wrapping approach.

-The problem with the former is that if I change the very beginning of a paragraph, my whole paragraph is marked as changed in diff.
+The problem with the former is that if I happen to change the very beginning of a paragraph, my whole paragraph is marked as changed in diff.
 The problem with the latter is that sentences tend to be quite long and thus wrap and changes are hard to track even though it is easier than with the former approach.

One line per idea

I came across this post which proposes to have line breaks between ideas (punctuation is a good indicator but clauses is probably even better).

 The problem with the former is that
-if I change the very beginning of a paragraph,
+if I happen to change the very beginning of a paragraph,
 my whole paragraph is marked as changed in diff.
 The problem with the latter is that
 sentences tend to be quite long and thus wrap

This offers the advantages of the line per sentence without its disadvantages. What's interesting is that this approach has been proposed at least as far as 1974 :) and focuses on changes rather than the initial blurb. Clever!

That's on paper at least. I will try this approach from now on and see if that works for me.

Encrypt your Dropbox or any folder with EncFS on Mac OS X

2013-07-01  |   |  tool  

This entry describes how to install EncFS on Mac OS X with homebew without breaking other tools using osxfuse (like TrueCrypt).

Why EncFS

I have been looking of a smart solution to encrypt a directory file by file. TrueCrypt is an awesome tool but does not play well with backups or Dropbox / Google Drive / SkyDrive like syncing: a TrueCrypt volume appears like a single big file which has to be synced entirely for each tiny change.

I just discovered this week-end EncFS. This is the exact tool I was looking for:

  • encrypts a directory file by file: each file and its name is encrypted
  • when one file is changed, only this encrypted file has to be synced
  • support for each major platform (Windows, Mac OS X, Linux)

I did choose EncFS over eCryptfe for its cross platform support.

Note that some metadata still leak in such system (as opposed to TrueCrypt) but I can happily live with that.

Installing EncFS with homebrew without breaking everything else

It took me far too much experimentation for my taste. Basically EncFS in Homebrew is using fuse4x which is incompatible with osxfuse - the now preferred solution. TrueCrypt - that I still use for disk encryption - happens to be using osxfuse and my attempts to make osxfuse cohabit with fuse4x and TrueCrypt to cohabit with fuse4x failed.

Here is the working solution:

  • install osxfuse via the .dmg install - I did install the MacFUSE compatibility layer for good measure
  • install TrueCrypt (.dmg install)
  • install the EncFS version compatible with osxfuse via brew

The last step requires to use a non standard recipe

brew install https://raw.github.com/jollyjinx/encfs.macosx/master/encfsmacosxfuse.rb

From what I gathered, osxfuse build is too complicated to be made a standard brew recipe. Too bad as I don't like to manage these externalities.


At the time, we are talking about:

  • Max OS X 10.7.5
  • OSXFUSE 2.5.6
  • EncFS 1.7.4

Using EncFS

Once installed, it is super easy to use

encfs ~/Dropbox/Private.enc/ ~/Private/
# or with a custom volume name
encfs ~/Dropbox/Private.enc/ ~/Private/ -- -o volname="Dropbox private"

mounts the encrypted ~/Dropbox/Private.enc directory as ~/Private/ and under the volume name Dropbox private.

If you add or change files from ~/Private, you will see an encrypted equivalent under ~/Dropbox/Private.enc.

To unmount, simply do

umount ~/Dropbox/Private.enc/

That's it. Happy secure data.


I was wrong in assuming a few things:

  • Dropbox can do partial sync of a big file, so the whole file is not reuploaded in its entirety. Reference here.
  • TrueCrypt does encrypt by block so changing one file does not change the whole TrueCrypt container file.
  • Mac OS SpaceBundle does roughly like TrueCrypt and split a bundle into files of 8MB each. Reference here.

It remains that encfs is a nice tool but not for the reasons I mentioned :)

Thanks for Renaud and Jekyll for pointing these errors. Bad karma for Jekyll for not resisting the urge to express it like a dick.

Autocompletion is crap

2013-05-28  |   |  java   tool   ide  

I can't believe autocompletion is still so stupid in 2013. Alright, I said it, I feel better. It's actually not quite true and a lot of smart things are going on in Eclipse or IntelliJ IDEA but completion remains incredibly stupid when it comes to discovering an API and offering the most appropriate choice.

It is very important for fluent APIs tailored to offer only the APIs that make sense in a particular context. So when the autocompletion offers you the full monty of useless methods of Object, it kills the hours of work an API designer put into his fluent API and its discoverability. Seriously notify(), notifyAll() and wait() x 3!

I developed, help develop or gave advice on a number of fluent APIs in Java including:

  • Hibernate Search and Hibernate Validator programmatic mapping API,
  • an upcoming Hibernate OGM programmatic configuration API
  • ShrinkWrap API
  • Hibernate Search Query DSL API

So I feel very personally offended when something gets between my work and the end user.


I use Eclipse these days and the sort by relevance works only in so far as relevance is synonymous to alphabetical. In other words it sucks... but in a predictably alphabetical way.

Eclipse autocompletion

IntelliJ IDEA

IntelliJ IDEA is smarter as it puts in bold the methods hosted on the type and leave supertype methods in regular.

IntelliJ IDEA autocompletion

If you dig enough though, you can find a setting

Sort lookup items lexicographically

by opening up preferences and search of autocompletion. Weirdly enough, if you uncheck this box, IntelliJ IDEA does the better thing and put the elements in bold next to each others.

IntelliJ IDEA smarter

And that concludes this half rant, half tip, half call to action to IDE developers. Yes I know but it takes at least 3 halfs for a good cocktail :)

Une tasse de thé podcast

2013-05-27  |   |  podcast   java   francais  

Eric Lefevre-Ardand vient de lancer un nouveau podcast sur la programmation et en Français: Une tasse de thé Podcast.

Comme son nom l'indique, le podcast est une interview sur un sujet précis autour d'une tasse de thé. J'aime bien ce format qui limite les interview à 15 minutes et donc garde la discussion centrée.

Au lieu de prendre votre thé ou café et de parler de The Voice ou de la 87ème rediffusion de Top Gun avec vos collègues, prenez votre balladeur et écoutez un épisode. Pour l'instant il fait ses épisodes tous les 15 jours.

Bonne chance à Eric. Garde le rythme :)

Making the best of Google Authenticator for One Time Passwords

2013-03-26  |   |  apple   tool  

You can't reorder tokens on Google Authenticator nor edit the associated description? Read on.

I use one time passwords everywhere I can. It's a little hassle but increases security by a whole lot. And the good thing is that more and more providers offer this:

  • GMail
  • Google Apps
  • Dropbox
  • Amazon Web Services
  • Your company if they are not too dinosaur-y

Go use one time passwords aka two factor authentication, you will thank me later.

I looked around on iOS and the most well known soft token application that supports both time based and event based tokens is Google Authenticator. Except that Google Authenticator's UI is really crap and buggy.

The edit button does not seem to function properly and nothing happens most of the time. The trick is to go to Legal information then back. You can now press the edit button and voilà! Things work. You can now:

  • reorder the list properly
  • edit the name under each token

That made my life much easier.

Multiple email aliases in iOS

2013-03-24  |   |  apple   productivity  

I have tons of email identities. Depending on which hat I am wearing, I use one alias or another. Most are behind my GMail address. It is easy enough to create and use multiple aliases in the GMail web client or even in Mac OS X's Mail app. But until recently I thought it was impossible with iOS Mail app.

It turns out it is possible but requires a bit of cheating. First off, instead of setting up your GMail account as GMail, set it up as IMAP. I already do that as I never give my GMail address (in case I change provider). Once setup, go in Note or any other editor and type the list of comma separated email aliases (including your primary address) and copy this line. For example:

scooby@doo.fr, scooby.doo@worldwildlife.org, scooby.doo@gmail.com

Then go to Setting -> Mail, Contacts, Calendars and select the email account you are interested in. In the Email field, remove the address and paste the list of comma separated email addresses. This whole gymnastic is necessary because iOS does not let you add commas in an email field.

Now you are good to go, when you create an email, you can change the email address with any of the aliases. Note that the last email in the list will be the default email (experienced on iOS 6.1.3).

I found the tip on iMore, they describe a more step-by-step explanation with some screen shot if you get lost.

Google Drive - the good and the ugly

2013-01-09  |   |  tool  

Google Drive is a bit confusing at first but the Dropbox like feature works reasonably well. They have a desktop client that works pretty much like the Dropbox client and syncs your local directory with the cloud.

This is quite handy when your friends have maxed out their Dropbox quota: Google Drive gives you 5 GB free. Images you store on Google Plus and files you store on Google Drive count against your quota. The Google Drive documents do not though.

Not everything is rosy in the Google Drive land though.

Trash or no trash

Data in your trash is counted as used space. It took me a while to figure that out and I could not get why my free space was lower that it should have. I don't think other services do that.


When you delete a non empty directory and then try to remove it from the trash, well nothing happens. Someone has forgotten to write the recursive part of the algorithm :) You have to go in each subdirectory and remove files and empty directories.

Simplistic client and speed

It seems to me that Dropbox syncs faster than Google Drive but I have not properly benched them so that might be subjective.

What is for sure is that the sync up cues on Google Drive are too simplistic. It tells you synchronization happens and that's it. Dropbox tells you how many files are uploaded and downloaded, what is the speed rate for each as well as the estimated time it will take. It's not gimmicky, it shows progress to the user.

Overall, I tend to stick with Dropbox despite the fact that it is twice as expensive per GB.

Name: Emmanuel Bernard
Bio tags: French, Open Source actor, Hibernate, (No)SQL, JCP, JBoss, Snowboard, Economy
Employer: JBoss by Red Hat
Resume: LinkedIn
Team blog: in.relation.to
Personal blog: No relation to
Microblog: Twitter, Google+
Geoloc: Paris, France