I found 2 Insects looking like this in my appartment:
Anyone knows what it is, its about 10cm large from leg tip to tip if it stretches out and capable of flight, seems not to have any inteligence to speak of. I could catch it and throw it out of my appartment but iam affraid its too cold outside?
Anyone knows what it eats? How long it lives?
Building a polynomial out of its roots is not particularly hard, one just multiplies the corresponding linear/first degree polynomials. But this isnt fast, even doing it recursively and using FFT based multiplication isnt all that great its still O(nlog2n). We can under some circumstances get rid of one of these log(n) factors as ill describe in a moment below. But first i wonder if below is the best that can be done or if iam silly and theres a faster or simpler way?
The idea of this method is not to build up the polynomial coefficients but to build up a vector of polynomial evaluations at evenly spaced points. Doing this for a linear factor “prototype” like x-1 on m points costs us O(m). next we build a sparse vector that is 1 where its index matches a root (and 2 for double roots,…) otherwise its 0. Now we can almost build our evaluation of the final polynom by convolution, just that convolution adds its terms while we need the factors multiplied of course. The solution is simply to convert the evaluation of the “prototype” linear factor by elementwise log() before convolution and by exp() afterwards. The value for log(0) does not matter for us except for numerical stabilty, we have to after exp() reset all roots to 0 anyway. With log(0)=0 one gets first order derivatives at the roots though. Also one can implement this using clasic log/exp and a complex value fft or finite field log/exp with a real or finite field fft. The last step of turning the evaluation vector of our polynom into coefficients can be done with a finite field fft. This make the whole thing run in O(m logm) time for a field size of m.
Whats annoying on it is that the the first part works with samples evenly spaced (aka an additative subgroup) while the second, that is turning the evaluation into coefficients is on a multiplicative subgroup of a finite field. In practice that means while my roots are along a multiplicative subgroup of GF(216+1) i have to apply the rdft over the whole field. which is kinda feeling like a waste of cpu cycles
Suggestions to improve this are welcome. Also alternatively if one knows of a linear time method to zero pad in the frequency domain a block of size 2n to twice its size than the resursive multiplication variant should also run in O(n logn) time.
My acer NB today: Critical temperature reached (101 C), shutting down.
And disablng power management of the HD produces errors after a while, not just today but always.
A little rant to keep my blog from rotting, firefox after 3.0 or so no longer works on kernels that randomize memory allocation a bit. Ones choices are either patching firefox or to disable the randomization for it. And we all know if one application needs all the security layers one can get then its the modern web browsers.
Not to mention how one can be so lame to have such bug open for ages and still not even produce an error message but rather run mmap() munmap() in an infinite loop.
About a month ago we (the ffmpeg team) voted about which name our NGO to which people soon will be able to donate should have. A sideeffect of that is that the world now has one more application to count votes using various condorcet methods, borda count and instant runoff voting. Get it from svn://mplayerhq.hu/michael/trunk/ffvotetov with your favorite command line svn client while its still fresh ;).
The vote itself went pretty well, we had a huge participation and it was quite fun :). Less funny was that murphy hit us and the winning choices “FFmedia/Foundation for free multimedia” domain name was already taken by some anonymous person through domaimsbyporxy, who asked us for cash even to just forward a message. Luckily the 2nd most popular choice “FFMTech/Foundation for free multimedia technolgies” didnt had that problem and was just by 1 vote behind so we picked that.
About which voting method is best, i dont know, but for our vote at least they all produced the same result most of the time while people added their votes. In that sense i wonder if any vote in reality that used a condorcet method actually ever needed rules beyond condorcet like the popular schulze method? Anyone knows? i checked debians past votes but it seemed they all had a condorcet winner
ld.so is the little thing that loads all your shared libs and binds all the referenced symbols to their definitions, well more or less at least. I think a better name for it would be a russian roulett linker, it binds symbols correctly most of the time but if it fails you dont want to be anywhere close to its line of fire ;).
The problems start with a mistake,oversight or let me call it a typo in the ELF spec. More precissely every reference in every object, be that the application or a lib will be resolved to the first matching symbol definition. The search order is a breadth first search starting from the application. This doesnt look wrong at first and thats why i call it a oversight or typo. The problem is for example if your application links to libz1 and libpng1 while libpng1 links to libz2. All references to libz2 in libpng1 will be resolved with things from libz1 and if we now assume these 2 are incompatible … boom. Had the ELF spec required a breadth first search starting from the object that contains the reference this problem and all the ridiculous mess that i describe below would not exist.
As the ELF spec requires this quite unpractical behavior one would expect that there would be some option that could enable a more practical search order. Sadly there is not in GNU ld.so, instead people recomand to use symbol versioning as a workaround.
Symbol versioning, as implemented by sun and later gnu has various purposes like finding the lowest version of a lib an application needs but in GNUs world it serves a much more important purpose, to workaround GNU ld.so fantastic misdesign.
The idea is that if everyone and everything uses symbol versioning then in our little example above libpng1 will use symbols from libz2 while the application uses symbols from libz1 and things actually work
The bad news is that symbol versioning is disabled by default, it can be enabled by using a version script or using –default-symver
The worse news is that you cant enable it if it wasnt enabled in a released binary without hell breaking loose due to the ld.so bugs i describe below
Sorry for the long intro above but the whole really is a convoluted mess that is hard to explain …
If you add a version to an existing library without bumping the soname you will hit ld.so bug #1, an assertion failure if an application compiled against the versoned lib is linked to a lib without versioning:Inconsistency detected by ld.so: do-lookup.h: 115: check_match: Assertion `version->filename == ((void *)0) || ! _dl_name_match_p (version->filename, map)' failed!
That one can be fixed by a single line change, commenting the assert out or as debian&ubuntu prefer by adding hundreads of dependancies (one for each use of the changed lib).
This bug is funny because if you rename the lib, load it with LD_PRELOAD and hexedit the filename out of it, it works and no more assert failure happens
But lets look at bug #2, ld.so will satisfy unversioned symbol references with the first symbol found versioned or not. This makes the coexistence of versioned and unversioned libs pretty much like walking a minefield. More specifically if you thought you can just turn versioning on with a ABI and soname bump, think again, it doesnt work because the old sonamed lib didnt use versioning the linker will bind references that where intended to the old lib to the new if that happens to come first in the list of dependancies.
And due to bug #3 ld.so will satisfy versioned symbol references with the first symbol found versioned or not. Unless the filename matches some test in which case bug#1 will end ld.sos life and also that of your application. Together with bug#2 this means if theres a lib with versioning and one without loaded, your references versioned or not can end up bound to either depending on luck the only thing you should not expect is that both will be bound correctly, because i think that cant happen at least not without very obscure tricks
Fix ld.so obviously, anything else is pure insanity, i dont even want to think further on what breaks and how it could be worked around. Heres a simple proof of concept patch but keep in mind this has only lightly been tested and it does not fix the root problem, that is searching is still in the silly order, just that now references will be resolved preferably with matching definitions and without random filename related assert(0).
A quick test and demonstration of the difference (id upload the tgz of the code if wordpress wouldnt disallow uploading tgz files)
./compileX.sh /lib/ld-2.9.so
Test for introducing versioning into A0 and a new A1 with versioning
Trying 6 A0:0 A1:2 B0:4 App:0
libA0 B:libB0 libA0 libA0
Trying 7 A0:1 A1:2 B0:4 App:0
libA0 B:libB0 libA1 libA0
Trying 14 A0:0 A1:2 B0:4 App:8
./app: ./libA0.so: no version information available (required by ./app)
Inconsistency detected by ld.so: do-lookup.h: 115: check_match: Assertion `version->filename == ((void *)0) || ! _dl_name_match_p (version->filename, map)’ failed!
Trying 15 A0:1 A1:2 B0:4 App:8
libA0 B:libB0 libA1 libA0
Test for introducing versioning into A1 and a new A0 with versioning
Trying 9 A0:1 A1:0 B0:0 App:8
libA0 B:libB0 libA0 libA0
Trying 11 A0:1 A1:2 B0:0 App:8
libA0 B:libB0 libA0 libA0
Trying 13 A0:1 A1:0 B0:4 App:8
./app: ./libA1.so: no version information available (required by ./libB0.so)
Inconsistency detected by ld.so: do-lookup.h: 115: check_match: Assertion `version->filename == ((void *)0) || ! _dl_name_match_p (version->filename, map)’ failed!
Trying 15 A0:1 A1:2 B0:4 App:8
libA0 B:libB0 libA1 libA0./compileX.sh ~/libcugh/eglibc-2.10.2/build-tree/amd64-libc/elf/ld.so
Test for introducing versioning into A0 and a new A1 with versioning
Trying 6 A0:0 A1:2 B0:4 App:0
libA0 B:libB0 libA1 libA0
Trying 7 A0:1 A1:2 B0:4 App:0
libA0 B:libB0 libA1 libA0
Trying 14 A0:0 A1:2 B0:4 App:8
./app: ./libA0.so: no version information available (required by ./app)
libA0 B:libB0 libA1 libA0
Trying 15 A0:1 A1:2 B0:4 App:8
libA0 B:libB0 libA1 libA0
Test for introducing versioning into A1 and a new A0 with versioning
Trying 9 A0:1 A1:0 B0:0 App:8
libA0 B:libB0 libA1 libA0
Trying 11 A0:1 A1:2 B0:0 App:8
libA0 B:libB0 libA1 libA0
Trying 13 A0:1 A1:0 B0:4 App:8
./app: ./libA1.so: no version information available (required by ./libB0.so)
libA0 B:libB0 libA1 libA0
Trying 15 A0:1 A1:2 B0:4 App:8
libA0 B:libB0 libA1 libA0
A week? ago my good old duron cooling fan, a ac copper silent 3 started to make funny noises. It sounded a little like a seeking harddisk. Well i obviously had to and did get a new one, i also considered getting a new CPU but seems socket A cpus arent available anymore. Well i wasnt seriously looking for an upgrade anyway, just curious.
Once i had the new cooler, (i bought the same as the previous) i thought i take the failing one appart. I expected to find some screws behind the stickers but no, there are no screws on the thing. To get it appart you have to pull the rotating part hard, nice design. As expected it was quit dirty in there, especially the ring magnet, i cleaned all parts except the ceramic bearing as there was some green lubricant on it that i couldnt replace if i cleaned it. Not really expecting it to work better i put it back together and, well it worked and was silent again :)
Murphy doesnt sleep though a day or 2 later the noise was back again :( So i repeat the procedure but sadly it made no difference this time. So being out of all options except 3, from which the first could damage my microwave and the second needs a sledge hammer that i dont have, i drop the thing by mistake, no really i didnt do it intentionally my 3rd option is actually taking the ceramic bearing appart and cleaning it with a bunch of paper towels. Ive taken a picture before doing that, sadly i didnt take more pics, like at the very start when it was really dirty …
The bearing is held together with a little metal ring that i somehow got off with a screw driver, and to my surprise it didnt fly through the room. After cleaning it and putting it back together i added a little bicycle oil. And it works and mosly silent. Anyone wants to bet how long it will last? I somehow think ill have to replace it with the new one soon …
Following is a true story of various odd events the happened a few years ago in my life, taken alone most and especially the begin would not be worth mentioning or writing about but together they might be.
I guess most people have someone who is important to them or who they love. In my case its Nadja, we’ve been in the same class in school which was indeed a long time ago. Somehow our paths parted, i always wanted to call her, but i didnt, and neither did she, nor have i heared anything from or about her, and neither did i ask. Well why should i have asked, iam not the kind that sniffs behind peoples backs about their lives, i always hated it when my mother did and wouldnt want to be treating others that way. Not that i had much contact to anyone i could have easily asked …
I was still living with my mother in her appartment, my father had bought his own appartment and left (IIRC) a year or so earlier. Without my father around, i was the only one left for my mother to talk to/blame/annoy. Now dont misunderstand me, my mother isnt evil (hmm or maybe she is ;) but i simply couldnt stand it anymore and left too. I also had a strange feeling that something wasnt right with Nadja … Being in my new appartment and not having my mother stand behind me all day long, i finally called Nadja, i still had the number from school time, to my dismay the number did not work. And to make it worse the phone company also had noone in their lists with a matching family name and street address, and that includes people that arent listed in the public phone book. Internet search engines also where a dead end, like they had been in previous years when i tried to find an email address of her. Being not too lucky with finding anything, i thought, “my phone number is in the phone book, my email is easy to find, if Nadja needs something she could find me easily…”, not that i was too happy about it but for whatever reason i temporarly gave up searching her. There where also many other things to do in my new appartment and my feeling that something was wrong, well i couldnt have known, i had to be imagining things.
I think it was spring, though i cant say that for certain, i was on my way to the supermarket around the corner, when i run into my grandmother. What was she doing here i wondered, well she told me that my other grandmother called her and said that my stove was broken and i couldnt make tea so she wanted to bring me a electrical heater plate thingy so i could make tee. Well, my stove wasnt broken and i didnt call either of my grandmothers. This thing left all of us a little puzzled, it seems someone with a male and young voice called my grandmother (the one from my fathers side) and pretended to be me (her phone number was in the phone book), telling her the story of a broken stove and tea, she didnt know the address of my new appartment so she called my mother and as she didnt reach her my other grandmother who then came to help.
IIRC the person said something like the following (in german)
“Iam [cant remember] from kurier, daily newpaper, could i speak with [name of my mother]”
I think for a moment and then tell him that, iam sorry but i do not know anyone by that name. He accepts that though apparently not very happily and we hang up. Not too surprissingly noone from “kurier” which actually is a pretty large newspaper here ever calls my mother.
It wouldnt be worth mentioning, where it not in relation to the following events, not that the other things at the begin of 2005 would be, but on this day mike melanson told me a little joke by email, something like “After the conference Diego, myself and the other multimedia hackers in attendance will coordinate an austrian road trip and locate you and see what happens when you are exposed to sunshine :)”
this was in relpy to myself declining the suggestion to meet everyone at linuxtag.
Some female claiming to be from lotto and wanting to speak with “frau michael niedermayer”, i mildly enraged tell her “herr niedermayer”, not too successfull she continues with calling me “frau michael niedermayer” which is somethinbg like “mrs./miss michael niedermayer” so i hang up. It has to be noted that she had no odd dialect and thus likely could speak german well enough to know the difference. According to my notes her phone number was “+43 6648194927”
Besides these calls, there was no lack of others who wanted to just ask a few questions for various statistics, and interviews in 2005.
As iam on my way home from supermarket, some guy in the street where my appartment is maybe he was 20-30 years old, wearing shorts. He said “Wast du schon an der sonne” which in english means “did you where already in the sun”. I ignored him and kept walking.
After that ive seen him many times sitting in the park, though never with a notebook or other normal hacker toy. Its also interresting to note that the last time ive seen him in the park was not too long prior to the next odd event.
(also neither diego nor mike look like him nor could they explain it when i asked)
I was in the park, spoke there on my mobile with my mother and then went home, on the way home, someone (female vioce) called “michi” from behind, not recognizing the voice nor expecting anyone I ignored it, the person didnt call a second time that day. 2 Days later same place same time, i was waiting for the traffic light to turn green when i spotted 2 girls diagonally across the crossroads, i didnt recognize either of them, though lets call them girl A and B for the sake of referring to them. The light turtned green and a little while after they where behind and out of sight someone from their direction called “niedermayer”, for some reason i ignored it, they didnt call again.
In the following 2 and a half months ive run across girl A (or at least i think it was her) several dozen times at random places. She always starred at me as if iam supposed to know her but i apparently didnt, at least i didnt recognize her. She was wearing something like jeans, tshirt and green sport shoes. I was thinking it must be someone from my school class, but i simply couldnt match her up with anyone, either way it wasnt Nadja so i really didnt care who she was or what she wanted, especially as she could have said what she wanted instead of just staring and IIRC once saying “hello”, well this reasoning shall turn out to have been possibly too naive.
As i walk home, just as iam entering the house, a guy maybe 10 meters before me on the street takes a photo of me, he appeared nervous, theres also nothing there, not even a trashcan that would be worthy of a picture.
As iam waiting at mc donalds for my 2 cheesburgers, someone to my right a few meters away is called by the name Nadja several times, she is or looks like girl B wearing a long black dress. She does remind me of someone from my school class but not Nadja, she doesnt look into my direction but the look on her face makes it very obvious that she is feeling very uncomfortable almost as if she wanted to do anything but being there playing Nadja which really is what she was doing. She also said no word at all.
Being somewhat confused and having received the 2 cheesburgers, i paid and left.
About 2 weeks later, again at mc donalds, as iam leaving, straight ahead along the street on its left side where a park is, i see an ambulance with blue blinking lights. I enter the park at its close corner and watch from quite some distance. I see someone looking like girl B walking together with several other people and ambulance man/doctors over the meadow to the ambulance. They dont seem to be in a hurry, neither is the ambulance after they reached it. I walk through the rest of the park and round the ambulance and then turn and walk home, the ambulance still standing at the same spot, still blinking blue.
After now seeing someone apparently knowning my name, being called Nadja and entering an ambulance i felt rather uncomfortable, that Nadja might not be ok, that i maybe didnt recognize her, I didnt really care who the weird people playing street theater where or why there where doing this, but i had to find Nadja.
The phone book, all phone companies, and google lead to nothing, but i found Marta, another one from my class, she could not explain who the weird people where but she could tell me what is with Nadja, Marta said Nadja died 2 years ago in 2003.
She did not know any details, but said that she is certain about it.
I did not want to belive this, and kept asking others i knew and ones i did not knew, as well as the official sources. Everyone who knew something confirmed that Nadja died in 2003.
Now if this was a fictional story then the death of Nadja, one of the best, most honest, righteous and selfless people i knew, would be the end. She was not the kind that pretended to be good while doing evil things, rather the opposite. Besides she is/was the most important one in my life. But reality is cold and mercyless, so the story cannot end here yet …
More weird people appear and watch me, they follow me around, watch what i buy in the supermarket, where i walk to, …
As iam on my way from the supermarket to my appartment, as i enter the house, seconds after passing a male thin guy, he behind me, says “niedermayer comes now” (in german).
I quickly rush to my appartment, but find nothing touched except maybe a chest of drawers moved a little, its top drawer is rather hard to move without moving the whole thing …
I buy a more secure lock and exchange the old against it.
My doorbell rings, iam in bed, sleeping. Tired i put on some clothes and stumble to the door. After opening it, i see a not too big guy with a woolen cap/hood. He very politely asks if he woke me, theres a somehow wicked smile on his face. He says he is searching for someone with the name “altendorfer” to renovate their appartment. I tell him politely that i dont know anyone by that name. He leaves and i head back to bed.
I walk by the entrance door of my appartment, noticing to my dismay that it is partly disassembled, more precissely the little hole with lenses through which you can look out is nicely taken appart and the metal plate in whichs center it is is very loose, to the point that there is a 10cm long and narrow hole one can look straight through to the outside, it was too narrow to stick ones finger through but a thick wire easily would have. To my further dismay both my keys and the security card needed to get replacement keys officially where placed at spots somewhat different from where i put them. The keys where hanging where the coats are hanging, though one was standing out straight horizontally from the keyring, a thing practically impossible to happen were they hanged there normally, but someone trying to be silent who was trying to return a single key quickly might very well place it like that.
The card, it was before and afterwards in my wallet, but now it was standing out, before, i had it sticked in as deep as possible as i knew i would not need it any time soon. Did i lock the door? When i was away: always, when i was at home: never.
Realizing that whoever was it, was long gone, i decided to block the door and go to sleep (a surely unwise choice, like never locking the door when i was at home …)
Next day in the morning i call the police, one of them, he looks like the average not too bright varity appears, he writes everything down, though as no real damage has been done and nothing stolen his interrest is low. he refuses to attempt to take fingerprints of the door pretending it was not possible to take fingerprints of smooth surfaces. I later file a complaint about this.
A sunday, being convinced that someone could have made a duplicate key to my appartment, i replace the lock again, thanks here go to my mother for buying a lock and bringing it to me on a sunday where most shops are closed.
I meet attila kinali, he having heared from all the mess here, jumped on a train to visit me. My appartment being a mess, ive offered/made no food for him. I was still far too confused about nadjas death to treat guests properly …
My mother tells me that someone has broken in, in my fathers office, his replacement keys, portable phone, a cammera, a harddisk and some money of a colleague has been stolen.
It is late in the evening, i go out for a walk, its dark, the ground is littered with fallen leafes. There are no people on the street except that every time i walk through some leafes a little while later i hear footsteps behind me stepping into leafes as well. I see no shadow from him, its clear he keeps enough distance not to cast any shadow too far ahead. I walk for maybe half an hour with him following me all the time, until i try to discreetly look back at a crossroads, but i was not discreet enough, he turns around and walks away at that very crossroads.
On many other days similar things happen, most of the time though there are several guys that switch positions, also they often waited at a future crossroads instead of litterally following behind.
I hear noises at the my appartments entrance door, as if someone was trying to open it. Walking there and looking through the repaired peep hole thingy, i only see someones back standing bend over in front. My first thought was that its some old neighbor or a relative of one who went to the wrong floor, but then a few moments later i decide to double check this, but too late, when i look again he is gone.
Gone far too quick and silent for an old neighbor …
The doorbell from the house door rings, i pick up the receiver and say “yes”, the awnser “police”. I press the open button, moments later 2 policemen, they dont look like the average dumb varity stand before me. They tell me that they came because of the break in a month ago. They ask many questions, look in all rooms, and listen to the various things i remember. They suspect that my mother is behind things.
I talk with my mother on the phone, and tell her that the guys watching/stalking me are always starring at me. Next day i find several people standing with their backs toward me standing at various points along the way i normally walk. They where quite noticeably starring in the air in random other directions …
I decide to do various random things and see how they react …
Iam on my way to a large shop (baumax), just before the shop i run into my grandmother (from my fathers side) she tries to convince me to come to her house. I decline explaining that it is too cold at her house and the shop is heated. She accepts that and leaves.
I buy a rope and one of these stick with a rubber pump thingies to clean the drain of a wasching basin, whatever its called in englisha plunger, so i have a seperate one for my bathroom and toilet. After i leave, while waiting for the traffic light to turn green so i could cross the street to reach the tram, someone behind me says “Nadja hat ihren job verlohren, die mussten eben den headcount reduzieren” (in english, “nadja lost her job, they just had to reduce the headcount”). I turn around but there where too many people to identify who said that.
For the duration of a week or 2 they follow me around missing no day, i always favored one supermarket during that time, at the end i see a couple in that supermarket, the woman i suspect was supposed to look like Nadja, she had similar “Ausstrahlung” (someone translate this to english)aura like Nadja. She also had thick hands, and i mean not that she was thick or her arms, just the hands, Nadja did not had thick hands. I guess its hard to find people looking like Nadja that are willing to play street theater. I guess they where also supposed to do something but they didnt, he just said a word or 2 to her, maybe something like “Lets leave” but i dont remember exactly. After that i notice fewer people watching/following me around. This could of course also have been a coincidence but its odd why they followed me around so carefully for 1-2 weeks and then just stopped.
I send nadjas mother a letter, hoping she would tell me something else than that Nadja is dead and hoping that maybe she has a clue who is behind that group following me around.
I didnt sent the letter sooner as several people like marta told me by email that i should leave nadjas mother alone and not ask.
The bell from the house door rings, i get out of bed stumble to the door, expecting the postman (there was a packet i was waiting for), i pick up the receiver and say “yes”, and wait, but noone awnsers, so i press the door open button anyway. A little later i realize it might be nadjas mother and put on some clothes and walked down to check but i see noone, so i walk around the block hoping to spot someone, again no luck.
I hear 2 woman talking a floor or 2 below me, i only catch a few phrases of the conversation, X: “… my daughter …”, Y:”… Michi … before 14-15 o clock few chances … many woman”, X:”MANY WOMAN?! …. is someone watching him?” Y:”A woman maybe”
X:”… frau [nadjas family name]”, After that, X left who possibly was nadjas mother, sadly i did not realize this quick enough. Who was Y? i dont know, Why was nadjas mother talking with a neighbor of mine instead of me? i neither know that.
The doorbell rings, its the postman, bringing back my letter that i sent to nadjas mother, unopened, it seems it was laying at the post office and nadjas mother did not take it from the postman or was not at home nor picked it up from the post office after that.
Not having heared anything from any neighbor yet about the whole, i go through the ones likely knowing and ask, its clear my suspicion is correct but they pretend not to know who had talked with nadjas mother, just trying to explain how she confused a few people who where looking at an appartment to rent at the floor above me with many woman coming to me. (and iam sure none of the ones i directly spoke with was Y)
Having heared various stories from members of my family and people from my class about other school comrades who died, i realize that alot more young people die than i would have guessed. So i decide to write a will, just in case …
Making sure my grave would be close to nadjas and not too close to people of my family (nothing against them but its called rest in peace for a reason). And that my computer stuff would end in the hands of some FOSS people. As well as for the very unlikely case that Nadja still is alive that she would get everything, not that i have much …
I receive an SMS
Its text is: “Happy birthday ALLES GUTE ZUM GEBURTSTAG wünschen Tanja und Mädels”
in english litterally: “Happy birthday everything good for (your) birthday wish tanja and girls”
Whats special on this, well its the day nadja died, exactly 4 years before. I also should mention that i have fewer SMS than i have fingers on one hand if i dont count advertisements and stuff from people i know. And its of course not even close to my birthday.
Short of that and a few other oddities, things normallized with the end of 2005. Comparing things its like counting oddities per week or day in 2005 while afterwards it was rather per month or year. So they are either gone or worked more discreetly after 2005.
Also note, the list of events above is intentionally not complete lacking things that iam sure are unrelated to the group following me around as well as a few things to prevent them from knowing what i missed.
How did Nadja die? There are many contradicting rumors, and after excluding what is clearly false, that whats left still leaves an accident, suicide and murder open. I dont belive it was an accident, she would have had to be stupid or unlucky, but she was very intelligent, but then i cant exclude that it might have been an accident. And iam certain it was not suicide, also noone suggested to me that it might have been suicide.
Who where the poeple following me around? Ultimately i do not know, at the top of the list though are private investigators hired by the copyright mafiaa, if it wasnt them some parts could be explained by 2 girls from my class and an unknown 3rd person hireing some private investigators. That 3rd person could be one of my parents, someone who knew nadja or some woman interrested in the ffmpeg maintainer. Motives could have been from just annoying me to finding information about me or Nadja.
Good arguments exist against most, it appears the person had difficulty identifying me at first, that would exclude my parents. But then its possible that not all events were caused by the same people …
Someone wanting to find information about nadja would have just asked, maybe pretending to be someone else than she was, but they wouldnt have done this kind of theater, the whole was just too much work for the return of no information at all, actually this text likely would tell such a person more than what they found out by their activity
Someone wanting to annoy/terrorize me really could have done more than the street theater they played, but then maybe it is hard to find people doing that “harder” kind of activity when one lacks contacts to the real mafia.
Gathering informatiuon about me, well i guess they did, not too much correct information once i realized that there are not just 1-2 girls from my class who i failed to recognize but even wrong information is information i guess
Note, if you send me any questions or comments by email, GPG encrypted&signed is strongly preferred!
Its a little while ago that i made that screenshot, anyway, i thought its funny so iam posting it here
After the little bit of analysing PRNGs in the last blog post, which PRNGs exactly seem good?
If one either needs a very fast PRNG or one has some means to easily test that the output is good enough (like looking to see if a noise filter produces no vissible aritifacts) then folllowing could be considered.
Linear congruential generators, Additative lagged fibbonacci generators or even just an array of random numbers that gets used repeatedly, …
Each of these has its serious flaws, LCGs have very poorly performing LSBs, that is the lowest n bits never have a period larger than 2n. ALFGs contain number triplets (the ones spaced like the taps used in the PRNG) that when used as coordinates in a cube would all fall in a single plane. Still these generators are often good enough, and have been used for a long time and are widespread, that is all C libs ive seen use either of them for rand() for examle.
If one wants a generator free of big flaws and that is still reasonably fast then the number of choices goes down, first there is
4 tap additative LFG (xi = xi-55 + xi-119 + xi-179 + xi-256 mod 2n) this one passed all of testu01 but has a obvious linear dependancy between its values.
Combined generators, these generators combine the output of several simple generators and generally pass all tests, many of them though are slow like CLCG4 which combines 4 LCGs, combined generators like fi = gi + hi also have the flaw that fi – fi+p = hi – hi+p when p is the period of g. This also means that fi – fi+p – (fi+q – fi+p+q) = 0 when p and q are the periods of h and g. Thus all combined generators which are made of constituent generators with “bruteforceable periods” are cryptographically likely very weak. A combined generator that is reasonable fast is KISS99.
Multiplicative lagged fibonacci generators, like for example (xi = xi-55 * xi-24 mod 2n) these generators also tend to pass all tests as long as only the most significant bits are used, that is for example the top 32 bit of a 64 bit generator. The least significant bit of such a generator is always 1, its next bit behaves like a LFSR identically to the least significant of an additative or xor based LFG. One trick to get rid of the least significant bit without ending up with just 31 or 63 bits is to use 2*a*b+a+b instead of a*b, this works because a and b are (have to be) odd in a normal MLFG and (2*A+1)(2*B+1) = 4AB + 2A + 2B + 1
“Anything” based on AES, SHA-1, MD5, …
These are PRNGs that are both slower and worse in terms of their output than others, examples are
Mersene twister, becuase its output is purely based on the XOR of previous bits thus being not nearly as good as some pretend it to be while it also isnt nearly as fast compared to other properly implemented PRNGs.
Combined generators with lots of modulo by non power of 2, these are slow …
Weak generators from which many output values are thrown away, again these are slow …
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