Older blog entries for TazForEver (starting at number 11)

16 Feb 2005 »

sizeof troubles

I always took for granted that my name -- Benoît -- was 6 chars long. I was wrong.
It's 7, UTF-8 speaking.
It took me some time this afternoon to understand why sizeof "Benoît" == 8 where i would expect 7. So i hexdump'ed my C file and realized that î is encoded as 0xC3AE. I'm glad that ASCII chars are still encoded on a single byte in UTF-8 so hacks like this one:

char buf[magic]; /* enough to hold "plop" */

are still 0k. I'll try to be less lazy and always code :

char buf[sizeof "plop"];

WTF is î ?

U+00EE LATIN SMALL LETTER I WITH CIRCUMFLEX
UTF-8 : 0xC3 0xAE

In French, circumflexes '^' on vowels often replace old French 's' :
- hôpital for hospital
- hôtel for hostel (= hotel)
- Benoît for Benoist
- côte for coste (= coast)
- etc
Benoît is the french for Benedict.

19 Oct 2004 »

Linux.Conf.Au 2004
May be some of you have missed the LCA2004 DVD event record. I have.
Here's the BitTorrent and MD5

Linux.Conf.Au 2004 Videos

24 Sep 2004 (updated 24 Sep 2004 at 07:51 UTC) »

PyPMU
I've hacked a small python wrapper for PowerMac Power Management Unit.

PyPMU 0.1.1

I'll soon make a control-based desklets on it.
I'd like to get the C backend used by GNOME battstat applet (supports only ACPI/APM, but i steel haven't been able to contact its maintainer. I think I'll have to provide a full patch to get a chance to get PMU support in ...

LibGTop
I'm working hard on libgtop. Fixed a nasty bug on Linux/Sparc64.
I've been granted access to 5 Solaris (sparcs) machines in a German University, and started to fix Solaris support. I still haven't decided if this will go 2.8.1 or 2.9.0 ...

24 Aug 2004 (updated 24 Sep 2004 at 03:04 UTC) »

python debugging : repr vs. str

Today, i've wasted one hour debugging a network app : receive an UDP packet, unpack it and insert data into a PostgreSQL database. Quite simple. The program sending data is written in C.

I was getting a pg error about bad queries. So i added a try...except and a print statement on exception. Everything looked OK, i didn't understand what was wrong. So i opened a psql shell and a python shell, dumped there my query. Ran fine. I was crazy. I spent 15 minutes sending packet and watching my error log ...

Then repr came !(Python lib)
so i replace my print 'Query was %s' % (my_query,) by print 'Query was %s' % (repr(my_query),) ... there were some non-printable chars in my data (C '\0' grrrr /me stupid). repr displays them, str doesn't.

Next time, i'll be more carefull with string and i'll use repr each time i'll need to print data in an error messages.

30 Jul 2004 »

A word about IronPython
I've downloaded IronPython 0.6. I've started an interactive shell. I type dir() brrrrrrrrrrrr ... finally got the result. Feels like a bit slow comparing to python. So i'm looking for application where IronPython is faster than every other python application. I'm thinking about JIT..

Benchmarks files and results DNABench.py doesn't provide the time module

Python 2.3.4

time python ~/Python/tmp/DNABench.py found AAAGTAAGCC at 1000000 it took 0 miliseconds found AAATGAAAAAG at 1048960 it took 1071 miliseconds found GAAAAAGTAAG at 1085441 it took 1947 miliseconds found TCTAAAAATAG at 1179694 it took 4075 miliseconds found ACGTGATGTAG at 1204636 it took 4697 miliseconds found AATAGATTCGG at 1548576 it took 13325 miliseconds found TCGTACAAATG at 1576094 it took 14024 miliseconds found CGGACGTGATG at 1599255 it took 14524 miliseconds found ATTCGGACGTG at 1689064 it took 16926 miliseconds found AGATTCGGACG at 1859204 it took 20982 miliseconds found TGATGTAGTCG at 1984902 it took 23993 miliseconds found AAATAGATTCG at 2000000 it took 24339 miliseconds Python regex took 24339 milliseconds

real 0m24.459s user 0m19.622s sys 0m0.067s

Pysco 1.2.2

time python /home/benoit/Python/tmp/DNABenchPsyco.py found AAAGTAAGCC at 1000000 it took 1 miliseconds found AAATGAAAAAG at 1048960 it took 309 miliseconds found GAAAAAGTAAG at 1085441 it took 631 miliseconds found TCTAAAAATAG at 1179694 it took 1220 miliseconds found ACGTGATGTAG at 1204636 it took 1529 miliseconds found AATAGATTCGG at 1548576 it took 4442 miliseconds found TCGTACAAATG at 1576094 it took 4645 miliseconds found CGGACGTGATG at 1599255 it took 4800 miliseconds found ATTCGGACGTG at 1689064 it took 5372 miliseconds found AGATTCGGACG at 1859204 it took 6490 miliseconds found TGATGTAGTCG at 1984902 it took 7377 miliseconds found AAATAGATTCG at 2000000 it took 7480 miliseconds Python regex took 7480 milliseconds

real 0m7.714s user 0m5.654s sys 0m0.029s

IronPython 0.6

time bin/IronPythonConsole.exe /home/benoit/Python/tmp/DNABenchIron.py Python regex took - milliseconds

real 0m44.932s user 0m0.060s sys 0m0.044s

Ok. obviously Psyco wins. IronPython is damn slow, so my shell experience was more than a feeling.
Btw, as you can see, i have a bug to report because IronPython doesn't find any DNA subsequence ...

19 Jul 2004 (updated 20 Jul 2004 at 05:59 UTC) »

About C# reflexion
I'm really disapointed about C# reflection.

If you want to retrieve the type, i.e System.Type, of a class, you have to use the typeof operator :

System.Type st = typeof(Stack);

sweet.

But if you want to retrieve the type of an object, you have to use object::GetType().

System.Type st = my_stack.GetType();

This sucks so much ... why typeof can't be applied to an object ? and this ugly method call makes me crazy ... all the C# API is full of these shits, it seems that may be half of the µ$ hackers were not aware of properties. And guess what, object::GetType() is overloaded ... We're so far from python __class__ attribute :

obj.__class__

KISS

This is a very bad design : it would have been too easy to extend the typeof operator and put everything else in System.Reflection ... i really can't understand why they did this. Even if i think C# is a bit better than Java, it just sucks. I hate these languages that are designed in 6 months... i can't understand ...

17 Jul 2004 »

emacs tip
I was interested in a feature that is present in a lot of IDE. I don't know if this has a name or if there's a patent on it : when you instert a (, [ or {, a ), [ or } is automatically inserted you don't get unbalanced (), [] or {}

(setq skeleton-pair t)
(global-set-key "[" 'skeleton-pair-insert-maybe)
(global-set-key "{" 'skeleton-pair-insert-maybe)
(global-set-key "(" 'skeleton-pair-insert-maybe)

very nice :D

19 May 2004 »

Mirror, sweet mirror

last night, i've installed a debian mirror for x86 on a small server (400MHz / 128 MB)

deb http://paulla.paulla.asso.fr/debian/

i'm pretty happy with it, 'cause it's going pretty fast : 100MB/s for everyone at university !

afaik, it's working :D

5 May 2004 »

python distutils vs. me
i've spend my week to find someone to build and maintain a RPM for pyxdg (Python bindings for FreeDesktop)

i recieved a mail from mandrake cooker maintainer explaining that they don't want the rpm to use the distutils in post intallation ... ok ...

python setup.py --help-commands | grep RPM bdist_rpm create an RPM distribution

Oh My God !

python setup.py bdist_rpm # ... ls dist/ pyxdg-0.5-1.noarch.rpm pyxdg-0.5-1.src.rpm pyxdg-0.5.tar.gz

so pyxdg will get soon into mandrake cooker :D

16 Apr 2004 (updated 16 Apr 2004 at 15:31 UTC) »

openMOSIX + Knoppix
I played with openMOSIX this nigh from 00h00 to 04h00 at university. As i've already worked with openMOSIX, i wanted to try it on live CD : found clusterKNOPPIX and Quantian. It's magic : just insert the CD and that's all, you can work on your cluster. I've worked with 6 Pentium 4 2GHz and run some benchmarks (e.g. cdparanoia + oggenc, etc): it did pretty fast :D.

Artouste : une plateforme libre pour l'enseignement et la recherche
Knoppix-based distro for scientific stududents
I'm working since last summer on a KNOPPIX based distro designed for scientific students. My friend and i have worked a lot to get rid of KDE (excessive memory consumption) in favor of XFCE4 which is also Qter :D We're having troubles with non-free software (e.g. scilab) but it's getting finalized. We have a big CD usage issue so we only have French locale : btw we are just targetting our own university and may be some other french universities.

French wiki
Pau Logiciels Libres Association
artouste-0.6RC4.iso
artouste-0.6RC4.iso.md5

xmlrpclib.Server("http://www.advogato.org/XMLRPC")
Some of you may have noticed that i have fucked up the blog diary because of an unbalanced quote and bold tag. The result was that the entire page was in bold and that the Edit page was broken (couldn't edit/preview anymore) ... i guess the tag parser failed -- if there is one. Amen, xmlrpclib saved us ! i've just opened a python shell : login, retrieve my last entry, edit, send and that's all :D

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