Name: dangermouse zenovka
Member since: 2003-08-14 09:12:50
Last Login: 2014-04-16 13:19:05
My first toaster was a C64, I learned BASIC by programming with my father and by copying programs from magazines in the period 1986-1993. Then, I wrote some Turbo Pascal programs on DOS and Windows 3.1 and 95 between 1990-1998.
In 2002, I had a small 80486 running with Mandrake Linux in my bathroom, but then I took a shower, the keyboard broke and killed the server with a flood of nonsense :-).. My laptop is called andromeda (the only deep sky object one can see with a binocular in a dark clear sky) and runs Gentoo Linux. My server was mainly built by Ninja and runs Gentoo as well.
I earned a master in CS with focus on computational sciences, astronomy and cryptography from ETH Zuerich in 2004. My ham radio call is HB9TVM. I do lot of things in parallel; although most of them fail (99.99999%), I do not worry too much :-). I learn by mistakes, and sometimes I repeat them, too.
My favourite programming languages are Lazarus/Freepascal (Delphi), C, C++, PHP and Java.
The three Open Source projects I am involved with:
This is the monthly report after the usual battles fought in cyberspace and beyond!
Third encounter with AIX
Mauri was playing with hanging puppets and Marti was already eating Spaghetti, but we were all waiting my father for supper on friday evening. The phone rang once, I called back but it was busy. It turned out that my father phoned, however he had to stop the phone call as someone from IBM support finally called him. He explained me that he had a strange black box in a corner of a huge hall full with wine boxes (each with 12 bottles of prestigious wine!) which refused to boot up. On the black box one could read IBM 520, and closer there was a label saying "Type 8203-E4A N/S G5-208 B4". The server went down on friday morning at 9:45 when an electrician doing maintenance work removed fuses to work safely. The whistling UPS run unheard for a while, and the black beast died right after UPS finished its juice.
The whole company could not work without this server through friday. (on which a DHCP server, a file server and a billing software run), so my father decided to keep trying and to skip supper. I could not resist when he mentioned the box was running AIX, so dangermouse mounted in his car and drove to the huge wine hall equipped with ananas pieces, biscuits and the two laptops virgibuntu and andromeda. Intermezzo for the fans: the Calibra car lost the front spoiler in a close encounter with the guard rail, which explains the broken blizzard sign, too.
But back to the problem: the local network was not lying neither on the usual 192.168.x.x IP range, nor on 10.x.x.x. It was between 172.16.x.x and 172.31.x.x which was unusual setting for us, and the confusion was great. On the LCD panel of the IBM 520 one could find out that it was started in modality A which was sort of diagnostic modality. The box did not have neither keyboard nor screen and was silent like the monolith of Space Odissey.
It had a strange HMS port, but we did not know what HMS was. Either the manual of 500 pages we found in Internet about HMS forgot to introduce what HMS was, or we were so tired that could not figure out.
The next day, when the kind technician of IBM came, we learned how to use HMS to revive the server, and learned about the smitty utility, and why one of the hard disk never lighted. For short time, I had the root password of the box, but when I tried to login to have a ride, the software owner already changed it. It is the third time I encounter an AIX, but never had the chance to login and discover its inners! In the end, our job reduced to get the printers back up and running, and to add a samba network name to the host file, which for some reason the resurrected blackbox did not want to resolve. When we left, I glanced one last time at the misterious IBM 520 box, and I felt like it was laughing.
I discovered that Virtualbox 4 has much better network support. I used this fact to setup a Fedora Linux 16 with the Sage libraries, a phantastic collection of mathematical software. Additionally, I found out that GPU libraries worked well under Linux, especially the Synapse support made by Lukas Gebauer. There is still some hope for the version II of GPU then! And from the outside, this Fedora thing should appear like a phantom computer on its network segment!
There were two lessons I learned with this puzzle: the first one is "let others help you"! In fact, I could not even solve the first level of the puzzle, while Virgi made it up to level 27. She explained me the rules of the game (we could not see them as we were logged in), and also some of the heuristics she was using, and to which mathematical problem it reduced (this can be found in the forum as well). I had a bad time passing the first level after that, but finally managed to do it! contagious told me that he used an external library to solve the Crossflip challenge. As my brute force solver barely brought me to level 60 and I could not find a way to implement Posa search, I decided to go with external libraries to defeat OneOfUs. I tried out many, including one of an author who made the claim P=NP. He was so kind to provide the C++ implementation, which you can't say of most of so called scientific authors. Still, his library did up to level 460, but then started going very slow. I teamed up with userfriendly, sharing what we discovered on the problem. After our briefing, he then skyrocketed to level 1000.
I kept stucked at level 460 knowing all what userfriendly knew. I worked through the night, but could not find the mistake in my solver implementation. I supposed an obscure error in the POST implementation of Synapse (the submitting part of the solver), but could not find any error after I created a test page to see what I submitted. Defeated, I went to sleep. I thought on all what I observed (including the fact that the "P=NP" solver in its slowlyness passed level 460) and then had the Zen flash, which each hacker.org puzzle hides. It turns out that my solver was in fact correct and it was solving the problem, just it was solving another problem which was not the one expected by hacker.org! I had a nasty mistake in the board generation for level over 242, but this mistake showed up only on bigger boards! The second lesson learnt is "if you think your code is right, it is. Look somewhere else!". For the record, the last level was solved in 20 seconds. The whole story can be seen here, when charting will work again.
Cheat Engine is an amazing Open Source tool which you can attach to any running process. Among other things, it identifies where integer variables are held in memory, so that you can modify them while you are playing. This helped me out a lot in a challenge I could not disassemble. I also tried "What in the World" without luck, but knowing what the sequences probably are. And failed on "Slim Image", too. On hacker.org, I often feel at the limit of what my mind can do and also what current software and hardware can do, which is a good introduction for the next section :-)
I read the Geometric Visions article of Michael Crawford, which is a great article not only about mental disease, but also about philosophy and about how people mind works in general.
I only had acoustic allucinations once, when i was living in a place close to a noisy rail station where i could not sleep. i never had problems with depressions or so, also because i can't focus on details, i do not care about details (which can be also a problem in life :-)
To tell the difference between voices and real life, i used Occam's rasor principle: if my reasoning started getting too complex, and one easier explanation (which might be hurting to myself) is easier, then i decided to believe the easier explanation and to fix my behaviour in positive ways. I found out that most of the time, complex reasoning was just an excuse to hide my misbehaviour. Occam's principle worked very well through my whole life.
I found the OpenFlashChart library for PHP and I am now pepping up deltasql with charts. The hope is that such chart experiments will help the GPU project as well!
As final links the history of Commodore International and of its founder, and a note on the strange Kaprekar numbers.
That's all folks!
for f in $FILES
if [ $f != "./resize.sh" ]
echo "Resizing $f file down to $1 per cent..."
# take action on each file. $f store current file name
convert $f -resize $1% "./resized/$f"
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