Instead of doing dichotomy by hand or with a calculator, I wrote the following Forth snippet using the gforth interpreter:

: guess 2dup + 2/ dup . ;
: init 0 999 guess ;
: big nip guess ;
: small -rot big ;



Here is the transcript of an interactive session (what I typed is in black, what was printed by gforth is in red):

init 499 ok
small 749 ok
small 874 ok
big 811 ok
big 780 ok
big 764 ok
small 772 ok
big 768 ok
big 766 ok
big 765 ok


For those not well-versed in Forth, here is how it works:

• guess takes the low bound and the high bound from the stack, put them back there and adds the middle value as well, and prints it.
• init starts a session by putting 0 and 999 on the stack and calls guess to print the initial value to be entered.
• big removes the high bound from the stack, leaving only the low bound and the previous middle value, then calls guess to get a new value.
• small replaces the low bound on the stack by the previous middle value, and calls guess. The stack manipulation and the call of guess would be done using -rot nip guess, and I took advantage of big by factoring it into -rot big.

That’s it. Who could now pretend that small isn’t beautiful?

It has been several weeks since I moved the ejabberd XMPP server for rfc1149.net on a new host which kept the same name as the old one. However, connections with gmail.com users are randomly working, while all the other domains my users interact with seem to have no problems at all. I have found several server administrators who experienced the same issue, and even read a suggestion to send an e-mail to the address xmpp@google.com which could supposedly solve the problem. The result? No answer, no working connection with gmail.com users.

What is needed to get Google to reread the new DNS information?

Edit: I received an answer from Jonas, a software engineer at Google. It looks like they are having troubles linking with Jabber servers located on the OVH network (as is mine, and as Ploum also wrote in comments), and they have contacted OVH. In the meantime, I may try to add another port to my Jabber server, update the SRV record, and see if it brings me more luck.

Et voila, on y est. La société civile des producteurs de phonogrammes en France (SPPF) poursuit quatre sociétés américaines au prétexte que leurs logiciels de peer-to-peer permettent de partager du contenu contrefait. Peu importe que ces logiciels servent à partager des logiciels libres ou de la musique légalement partageable, le fait qu’ils puissent être utilisés pour partager des œuvres dont la redistribution est interdite par leurs ayants-droits suffit à donner une chance à la SPPF de gagner une telle action en justice. Le texte de l'article L335-2-1 du code de la propriété intellectuelle est formulé en ces termes :

« Est puni de trois ans d’emprisonnement et de 300 000 euros d’amende le fait :

1° D’éditer, de mettre à la disposition du public ou de communiquer au public, sciemment et sous quelque forme que ce soit, un logiciel manifestement destiné à la mise à disposition du public non autorisée d’oeuvres ou d’objets protégés ;

2° D’inciter sciemment, y compris à travers une annonce publicitaire, à l’usage d’un logiciel mentionné au 1°. »

Notez bien le « manifestement destiné à la mise à disposition du public non autorisée d’oeuvres ou d’objets protégés » employé ici : c’est lui qui peut faire la différence, le juge devant apprécier si cette condition est respectée. La loi pénale étant d’interprétation stricte, c’est peut-être ce qui sauvera nos logiciels de partage du jouc de la justice.

On pourra également remarquer qu’en cas de succès de l’action judiciaire, la SPPF aura beau jeu de la prolonger par l’attaque des fournisseurs de distributions GNU/Linux, car ceux ci fournissent en général certains des logiciels mis en cause (Azureus par exemple) dans leurs paquets. Ainsi que de tous ceux qui fournissent des dépôts, notamment en France, contenant une copie de ces distributions GNU/Linux (je pense à la quasi-totalité des fournisseurs d’accès par exemple). D’ailleurs, une des sociétés attaquées actuellement n’est autre que SourceForge, la plus grande plate-forme de développement de logiciels libres. Et ce uniquement parce qu’elle héberge et distribue un des logiciels de partage incriminés, même si la société ne contribue pas directement à son développement.

Oh, vous me direz que ça ne peut pas arriver chez nous, qu’on ne pourra pas interdire la distribution de logiciels libres sous prétexte que certains pourraient les utiliser illégalement. On parie ?

I remember myself asking the teacher: “Would it be ok to run a person’s blood through a machine that temporarily increases its pressure in the presence of oxygen?” She looked surprised and told me she didn’t know.

Two days ago, I watched an episode of House M.D in which Dr. House puts a patient into an hyperbaric oxygen chamber to cure a patient from carbon monoxide poisoning. Not quite the same thing as the derivation I was thinking about, but the same principle, increase the blood pressure in an oxygen-saturated environment. This reminded me of the question I asked when I was a child. Twenty years later, I’m proud to know that my idea was not that stupid.

Networked disks are very useful. At home, they allow you to access your data from any computer on your local network without needing to keep a machine acting as a file server turned on all the time. But wait! You could use a networked disk to store songs and movies that you have illegally downloaded, couldn’t you?

Don’t worry, your networked disk will make sure you comply with the law and much more . Did you intend to store music that you legally downloaded from Jamendo and let your spouse and children access it? Too bad, since it may infringe someone else copyrights, Western Digital seems to think that it is best that you do not share it at all, just in case:

Due to unverifiable media license authentication, the following file types cannot be shared by different users using WD Anywhere Access.

If these file types are on a share on the WD My Book World Edition system and another user accesses the share, these file will not be displayed for sharing. Any other file types can be shared using WD Anywhere Access.

As a friend send to me, “sure, sharing 1 tera bytes of text files looks very appealing”. This post could have been titled “how DRM (Digital Rights Management) can hurt the world even when they are not used” or “we assume that you are a criminal”.

prefer-family = IPv6

in either /etc/wgetrc (system wide) or $HOME/.wgetrc (user settings).

cd /usr/src/linux

which always resulted in

cd /usr/src:linux

(incidentally, when typing the above strings, I had to fix the first one and the second one came naturally buggy)

On a French keyboard (AZERTY layout), / is obtained by pressing shift and :. I first thought that my laptop keyboard was misfunctioning. But it happened on my home computer as well. I then thought I had become unable to properly release the C key before pressing the shift one, but no, I think I found a real bug somewhere: this problem occurs only when a key amongst the lowest left part of the keyboard (near to the shift, namely one of the WXCV letters on my keyboard) is rapidly followed by a shift.

Let’s make a test: while running a X11 server, press the C key, let it pressed so that you turn the auto-repeat mode on, then press shift (without releasing the key). You should, at least under Linux with Xorg, see something like:

ccccccccccccccCCCCCCCCCCCCCCCC...

But what I get is:

cccccccccccccccccccccc...

The shift key is ignored. Note that it works fine with the right shift key though.

For a fast touch typist (as I otherwise luckily am), this is rather unfortunate; the combination of one of those wxcv letters followed by a slash happens to me at least fifty times a day, often much more than that. Since I cannot reproduce that on the Linux console, I will for the moment put the blame on my X server.

1. a quotation to execute when the test is true
2. a test quotation

For example, I wanted to be able to find the smallest power of two greater than or equal to an arbitrary number (here 34098) by doing:

1 [ 2 * ] [ dup 34098 < ] while

(of course there are much better ways of doing that, such as 34098 2 * 1 + 2 /i but that's not the point here)

This would be much easier if we could recurse from within a block (by using a recurse word). Let's start with that:

SYMBOL: recursive-block

: set-block ( quot -- )
  recursive-block set ;

: recurse ( quot -- )
  recursive-block get call ;

: with-recurse ( quot -- )
  recursive-block get >r
  dup set-block call
  r> set-block ;

A quote passed through with-recurse can use the recurse word and re-execute itself.

Now that we have recursion, it is easy to implement while using currying:

: while ( quot quot -- )
  swap [ call recurse ] curry [ slip when ] 2curry
  with-recurse ; inline

Note that inline is used here to give the optimizing compiler a chance to build the complete quotation at compile-time if both quotations given to while are statically known.

To create a vocabulary recursion containing this code, one can create a file extra/recursion/recursion.factor containing:

USING: kernel namespaces ;
IN: recursion

<PRIVATE

SYMBOL: recursive-block

: set-block ( quot -- )
  recursive-block set ;

: init-block ( -- )
  [ "recurse called without with-recurse" throw ] set-block ;

PRIVATE>

: recurse ( quot -- )
  recursive-block get call ;

: with-recurse ( quot -- )
  recursive-block get >r
  dup set-block call
  r> set-block ;

: while ( quot quot -- )
  swap [ call recurse ] curry [ slip when ] 2curry
  with-recurse ; inline

MAIN: init-block

Loading this library can be done by issuing the following command in the listener: "recursion" run.

That's all folks.