Posts by Mushy-pea

Hey. I've been working on a home brew game since late last year, writing an engine in Haskell and GLSL that includes 3D graphics, basic physics and programmable game logic. The version in the second video shows the first appearance of lighting and importation of OBJ files (the cube was made in Blender). I'm aiming to do a 3D remake of the game ZZT, a bit like these guys did with Sonic the Hedgehog. The game logic can be programmed using a scripting language I made called Game Programmable Logic Controller (GPLC), which allows for the switch and lift interaction in the first video. Much more complex systems and puzzles could be built. The next steps are adding non - player characters and further logic such as game saving. I'm going to eventually release this open source, after the remaining mountain of work with unknown duration. If anyone is interested in contributing to level design or sound let me know. I guess it's a long shot, but some people may like learning semi - arcane custom processes for the fun of it.

Steven

Demo clip 1

Demo clip 2

Hi. In August I built a PC using a second hand Biostar TA990FXE "Extreme Edition" motherboard and AMD FX-6100 six core CPU @3.3 GHz at the core of it. I recently installed the Oracle Virtualbox VM on Windows 10 and tried running a couple of Linux and BSD OS instances, during which I noticed that task manager was reporting (at times) the CPU clocking at up to 3.87 GHz (or ~17% over the quoted maximum). Note that over clocking options were disabled in the BIOS at the time. I am just curious as to whether this is due to the VM using hardware virtualisation and some feature of the CPU or motherboard detecting this and increasing the clock speed limit. Has anyone seen this kind of behaviour on your own systems?

An SP network is indeed the design principle I based this on. However, it isn't true that the S-Box is just a permutation and this can be shown using the scaled down example of the Sub Character step given earlier.

seq (1) = 1 3 0 2
input data = 0 2 3 1 2 0 1 1, output = 1 0 2 3 0 1 3 3

in binary: 00 10 11 01 10 00 01 01 01 00 10 11 00 01 11 11

That there are 7 1s in the input and 9 in the output proves this is not a permutation. This is a good job as if it were the two steps could be seen as a single permutation of the input. As for the P-Box (Swap Bit) my thinking is it's perhaps too simple. As a positive (to my mind) each bit in the input can be placed in any position in the output, meaning all permutations are possible and bias can only come from the entropy in the key. As a possible downside the same operation is used each time the P-Box is run unlike in more complex ciphers like AES, where a sequence of round keys derived from the main key are used. I'd be interested to hear your thoughts on this.

You may be right about there being issues with key confusion. I'm going to do a statistical test for the strict avalanche criterion at some point, which should shed some light on this.

Steven

That appears to be right except (the mutation) where you've put i = 0 to 21 and i = 0 to 126 the upper bounds should be 20 and 125, to make 21 and 126 iterations respectively. I didn't state in the first post that in the examples the program was run in counter mode with an IV of 0, or equivalently "AAAAAAAAAAAAAAAAAAAAA". In this mode the block cipher is fed the sequence ["AAAAAAAAAAAAAAAAAAAAA", "AAAAAAAAAAAAAAAAAAAAB", "AAAAAAAAAAAAAAAAAAAAC",...] to encrypt, the result of which is xored with the plaintext.

Steven

This look up table can be used to convert key (2) to seq (2).

ABCDEFGHIJ K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  a  b  c  d  e 
0123456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

f  g  h  i  j  k  l  m  n  o  p  q  r  s  t  u  v  w  x  y  z  0  1  2  3
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

4  5  6  7  8  9  SPACE  /A /B /C /D /E /F /G /H /I /J /K /L /M /N /O /P
56 57 58 59 60 61 62     63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78

/Q /R /S /T /U /V /W /X /Y /Z /a /b /c /d /e /f /g /h /i /j /k /l  /m  /n
79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101  102

/o    /p  /q   /r   /s   /t  /u  /v  /w  /x  /y /z  /0  /1  /2  /3  /4 
103  104  105  106  107  108 109 110 111 112 113 114 115 116 117 118 119

/5  /6  /7  /8  /9  SPACE
120 121 122 123 124 125

Hi. I just thought I'd post this photo of me and some graffiti lights in Bristol. I'd never come accross such a thing before, but given the city's traditions I perhaps shouldn't be surprised.

Steven

Perhaps I could have explained this a bit better. Another way to look at it is to start from the sequences of numbers that are input to each step and work back, but with a simplified example. If the block size was 16 bit and this was divided into 2 bit values (shown in decimal form) in the Sub Character step an iteration would look like this.

input data = 0 2 3 1 2 0 1 1, seq (1) = 1 3 0 2, output = 1 0 2 3 0 1 3 3

The meaning of seq (1) is: substitute 0 with 1, 1 with 3, 2 with 0 and 3 with 2. There are 4! possibilities for seq (1) as each value from 0 - 3 can only appear once for the step to preserve the information in the input. One could represent seq (1) by a string in the set "ABCD" by saying [A = 0, B = 1,...], giving key (1) = BDAC. In the Swap Bit step the input data is treated as a block of 16 bits, each of which has its position in the output determined by the value of the entry in seq (2) with the equivalent position.

input data = 0 1 0 0 1 0 1 1 0 0 0 1 1 1 1 1, seq (2) = 14 4 5 9 7 2 15 8 0 3 1 6 13 10 12 11, output = 0 0 0 0 1 0 1 1 1 0 1 1 1 1 0 1

As this changes the order of the bits there are 16! possibilities for seq (2). One could represent seq (2) by a string in the set "ABCDEFGH/". A letter on its own is read as [A = 0, B = 1,...] (scheme 1). A letter proceeded by '/' is read as the number given by putting the letter through scheme 1 plus 8. This gives key (2) = /GEF/BHC/H/AADBG/F/C/E/D.

Steven

Hi. I've developed a bit of an interest in encryption as well as programming in Haskell since I last used this forum. So I decided to build a symmetric block cipher and test its properties to gain more of an understanding of such things. This is for research purposes as they say. I'm not planning to use it with any sensitive data, but I thought it would be interesting to set a little challenge. The code is below together with a description, an example ciphertext and key for demonstration. There is then another ciphertext which contains a Bitcoin address (holding 0.0148 BTC), its private key and some further text. Sorry the prize is so puny but I did say I'm not using sensitive data. So, if anyone is interested in this kind of thing feel free to go for the coin (which will stay there for at least 365 days) and leave any "constructive" comments.

-- Cipher 126 code by Steven Tinsley.

module Main where

import System.IO
import System.Environment
import Data.List
import Data.Bits
import Data.Array.IO

char_set = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 /!\"£$%^&*()-_=+[]{};:'@#~\\|,.<>.?\n\t`¬¥èéùìòÇØøÅå§ÄÖÑÜ¿öñüà€©®½¾"

dec_bin1 :: Float -> Float -> [Int]
dec_bin1 d_num factor = if (d_num - factor) < 0 then 0 : dec_bin1 d_num (factor / 2)
                        else if (d_num - factor) == 0 then [1]
                        else 1 : dec_bin1 (d_num - factor) (factor / 2)

dec_bin0 :: [Int] -> [Int]
dec_bin0 [] = []
dec_bin0 (x:xs) = pad0 (dec_bin1 (fromIntegral x) 32) ++ dec_bin0 xs

pad0 :: [Int] -> [Int]
pad0 …

Hi. I'm working on some Haskell code that takes some string input and processes it to return a list of integers, the reason for which should become clear when the app. eventually get finished. The list processing functions do what I want when I call "parse_data (contents)" in GHCi, but when I run the whole program they terminate early and only return the result of the first two characters of input.

-- These functions convert numbers between decimal, binary and hex bases and are used for encoding and decoding maze
-- descriptions

decimal_binary :: Float -> Float -> [Int]
decimal_binary d_num factor = if d_num < 0 || d_num > 255
                            then [0]
                            else if (d_num - factor) < 0
                              then 0 : decimal_binary d_num (factor / 2)
                            else if (d_num - factor) == 0
                              then [1]
                              else 1 : decimal_binary (d_num - factor) (factor / 2)

pad :: [Int] -> [Int]
pad xs = take 8 (xs ++ [0, 0, 0, 0, 0, 0, 0, 0])

binary_hex :: [Int] -> [Char]
binary_hex xs = (count1 (take 4 xs)) ++ (count1 (drop 4 xs))

count1 :: [Int] -> [Char]
count1 xs = case xs of
         [0, 0, 0, 0] -> "0"
         [0, 0, 0, 1] -> "1"
         [0, 0, 1, 0] -> "2"
         [0, 0, 1, 1] -> "3"
         [0, 1, 0, 0] -> "4"
         [0, 1, 0, 1] -> "5"
         [0, 1, 1, 0] -> "6"
         [0, 1, 1, 1] -> "7"
         [1, 0, 0, 0] -> "8"
         [1, …

Hi. I've been trying to get this simple function in Haskell to let me call it for many hours and come to a problem I can't find an answer for. The function is of type

Float -> Float -> [Int]

so I need to pass it two Float values. I've fed the result of getLine (d :: IO String, I believe) to the "det" function, where it's passed through a "show " and then a "read" function. I think this should yield a value of type Float and the compiler seems to agree, as it compiles fine. Then, at runtime I get a "Prelude.read: no parse" exception. The code is below. Can anyone explain what I'm doing wrong here?

module Main where

decimal_binary :: Float -> Float -> [Int]
decimal_binary d_num factor = if d_num < 0 || d_num > 255
then [0]
else if (d_num - factor) < 0
then 0 : decimal_binary d_num (factor / 2)
else if (d_num - factor) == 0
then [1]
else 1 : decimal_binary (d_num - factor) (factor / 2)

det a = read(show a)::Float

main = do putStrLn "Enter an integer in the range 0 - 255: "
d <- getLine
putStrLn "The binary form of your input is: "
print (decimal_binary (det d) 128)

Steven

Hi. After many years of having a hobbyist interest in programming but doing other things for a job, I've decided it might be time to attempt a career change to application development. The other areas I've worked in, such as teaching English to non - native speakers, aren't directly relevant to this line of work. However, I've got a degree in Physics and I'm considering doing a course that leads to the Oracle Certified Professional Java SE Programmer qualification. Obviously, I'm doing research into the merits of the qualification and the job market for programmers in the UK.

I'm interested if anyone here has got this qualification or has an opinion on it's usefulness when applying for entry level Java development jobs. Any advice would be appreciated.

Steven

Part 2

He found that the duration into the past the messages were sent was proportional to the distance between the two boxes. As this duration was equal to the light travel time between the boxes they would have to be 300000 km apart for a message to be sent one second into the past. Kevin wanted to send messages at least a minute into the past but realised this would mean the boxes being 18 million km apart. This didn't seem to be very practical and he was in a quandary about what to do for several weeks. Then he met one of Marc's friends, a man called Phillip Locket, when they were introduced during an after work drink. Phillip was Canadian and had met Marc while they were working together on a big software project at Phillip's university. “So, Marc tells me you're a bit of a footballer.” said Phillip. “Well, I play in a few games for a university team, but it's only a bit of fun really.” said Kevin.

“Speaking of fun, are you good at any pub games like pool or table football?”. “Well yeah, I play a bit of table soccer.” answered Phillip and just at that moment noticed the table football game standing in one corner. “Ah, could that be a challenge I hear?”. Marc smiled slightly. It was interesting that while not being the most competitive minded of people generally speaking, Kevin became quite the sportsman when it came to …

Hi everyone. You may remember that I posted a short story here about a year ago. I've cobbled together another little tale and, as the first one seemed to be appriciated, I thought I'd give it an audience here in two parts. Hoping for your amusement, fellows.

The message (part 1)

The office where Kevin Salmon worked was painted a rather unusual and somewhat deep blue, which was not entirely to his liking. Although, he consoled himself with the thought that this was not where the most important work was done anyway. He was a professor of quantum information processing who defined his work as “mainly experimental”; the laboratory was where the real discoveries were made or, just as importantly, not made. I should explain the proceeding a little more. There are basically two kinds of physicists in the academic world; theorists and experimentalists. The theorists attempt to build models (or theories) of how an aspect of the world works and then work out how the models predict the real world should work. The experimentalists do experiments to see if the world does work as predicted and their results therefore either support or disprove the models. If a model is shown to make incorrect predictions it must either be thrown out or modified.

Note however that a model can never be proven as there is always the possibility that a future experiment will contradict its predictions. It was with these thoughts in mind that Kevin was considering …

and then after that Jane wakes up and realize that it was all a dream? :)

Good story anyhow.

I'm afraid there's no happy ending this time. Although, an act of selfless heroism such as Johnston's could been seen as a positive thing in itself. After all, he could have just shoved Jane into the closet and got rid of her to save himself. In the dream I had I ran into the closet, closed the door and disappeared as a woman chased and tried to stop me. Then I took the role of some other spirit and went into the woman's brain, telling her "I will show you the meaning of nothingness," as she helplessly tried to keep this terrible knowledge at bay. Needless to say, it was a lot darker than the story.

Steven

Thanks. I'm an English teacher so standards must be kept high :) . As promised, here's the rest of it.

Part 2

Jane stared curiously at the empty closet for a few seconds in silence while a cold sweat seeped through the skin of her face, feeling her pulse quicken and a sense of unreality set in. Something intuitive within her said clearly that this was no magic trick or prank. “Before you ask more about it,” said Johnston just stalling a question on her lips, “look at the transport manifest again.”. She looked and found that the 30 inch monitor had disappeared from the list of transported items. “It has not only been removed from existence in the present moment but from every moment in which it ever existed.” Johnston explained. “The only evidence left that it ever existed are the memories we have of it, because we saw it put into the closet. That's how the machine works. It's come in quite useful over the last year or so when one of our guys has broken a clients item. As long as I could get the damaged thing here the problem was as good as forgotten. Literally.”.

“So it's a machine of some kind. I won't pretend to have the mind to understand how it works. How did you find out about it though? Where did it come from and how the hell did it get into the office?”. Jane had composed herself again and …

Hi. I haven't posted here for some time but I'm still a big fan. Anyway, I had an interesting dream last night and it inspired me to write a short story based on it. I hope no one minds if I post the first part of it here for your (possible) entertainment.

Existence and the lack of it (part 1)

Jane Paters worked in the London office of a small commercial relocation company. Their business centred around helping other companies move their operations from one office to another, quickly and with a minimum of down time involved. Jane was a secretary and receptionist who had become a dependable and well liked character in the office. It was Monday morning and she was just returning to her desk after a tea break when Mr Johnston the site director walked in carrying a large computer monitor with a crack right across the screen. It was evidently quite heavy from the concentrated look on his face and he was soon struggling to open the door to the store room while supporting it's weight.

“Can I give you a hand there Johnston?” asked Jane in her Yorkshire accent, already walking over to help. For some reason Mr Johnston preferred people to use his second name as if it were his first. “Oh, thanks Jane. If you could just hold the door open from the inside that'd be great.”. She duly obliged and soon they were both inside with the monitor on …

Hi. I live in Japan in a city just outside Tokyo, although only for a few more weeks. Before a train's doors close here, a jingley little tune gets played to warn people still descending the steps to the platform they need to hurry up. The variety of tunes available depends on the line you're on and they reflect a wide range of human emotions; contemplative, happy, rushed, peaceful etc.

Does anyone think this idea would work well in the US or UK, or if it might just prove too annoying for commuters?

Steven.

I would be interested in a link to look at to see what is really being said. There is so much 'mushy' use of language wrt budget deficit vs national debt, I like to see what underlies the conclusions.

Here you are: http://www.gpoaccess.gov/usbudget/

I admit that I haven't read any of this yet.

Steven.

Hi. I recently read that the current US federal budget predicts the US debt to GDP ratio will reach over 70% in 2011 and about 80% by 2020. This analysis assumes fairly strong economic growth. The question that springs to mind is, if a budget surplus can't be achieved during a ten year period of growth, when can it?

Steven.

Apple has been engaging in the kind of anti-competetive behaviour you mentioned for some time now. So, I found it quite amusing when they were sued by Cisco over the iPhone name.

The only way to gaurd against servers and networks overloading when under rare and extremely heavy load is to have large amounts of spare capacity sitting around doing nothing most of the time. This is potentially quite inefficient in terms of energy consumption and maintenance costs. I would much rather effort were invested in making the transport infrastructures more resillient.

When you say "the DNS is changed to point towards porn and phishing sites", do you mean that (for example) the locally stored DNS entry for www.hsbc.co.uk could be repointed to a fake version of this site?

A teacher is more likely to be bullied by one of the staff of their school than it's pupils. This is something a member of my family has experience of.

Perhaps Sun deliberately make Solaris a bit tricky to use so they can keep selling IT support contracts for it. I wouldn't blame them, seeing as the software itself is free now. As to whether Solaris is actually unfriendly to the user I couldn't comment much, having not used it since my University days (and that was a nicely pre - configured system). I know that some people say the main BSD distributions tend to be harder to use than Linux. I can't agree with that based on experience. Thing is, once you've seen how packages work on netBSD (for example) it's "plain sailing" from then onward :) . With Linux there are at least three different package managers just among the major distributions.

The harsh conditions mentioned in Bill's report are primarily the cosmic rays the silicon components of a computer are exposed to in space. A cosmic ray is a fast moving proton ejected from the sun. If one hits a register it can cause a cascade of ionisation that can flip a bit (i.e. a 1 becomes a 0).

It is interesting that the BSD license is more permissive of software being taken back into the propriatory domain than the GPL is. I mean this in the sense of the long and tiresome lengths the BSD team had to travel to free themselves from claims of pirating by AT & T.

By the way, I have no idea if the algorhythm I thought up was new or already exists. It is so simple that someone else probably thought it up and discovered it's major weakness (lack of cipher scaleability) years ago. In this case, I merely discovered the method (not invented as I said above). One wouldn't want to plagerise :) .

I invented an encryption algorhythm today and used it to "hide" the information in an unused password I came up with. This was done on paper, not with a program. However, I am planning to start laying some code down for this today (in Haskell, partly as an exercise to help me learn the language). The question I'm interested in is: how easy will it be for you tech savvy folk at Daniweb to break my key? The encrypted string is:

uwiBmz24

The following information is offered on the problem:

1. The plain text is a combination of an English place or person name and a number.

2. The set used is [a-zA-Z0-9] in Perl regex notation. It runs from 0 for "a" to 61 for "9", in the order shown in the set.

3. The algorhythm used is based on finding all the factors of a hidden seed number. Breaking it would require the finding of all these factors. In this case the cipher strength is 5 bit and the key is 48 bit.

4. I am going to mirror this post with one on my home page in an attempt to get some more interesting content on the site :p . Feel free to remove this bit if you're a mod and you think it's a bit spam like.

5. The prize is: you'll have the option of trying the challenge again with a stronger cipher (once I can get a …

I think Dell has a decent reason to deprecate Vista; it will make there high end PCs look like they've got Sinclair Spectrum chips inside. 512 MB to boot the computer up? My brain doesn't have that much memory (and it's a high end model I can tell you). But (joking aside), I would imagine Dell will offer customers the option of choosing Vista or Linux (or both) on these machines. That it is shocking that a major hardware vendor doesn't start pre - installing the latest MS operating system by default as soon as it is released just shows how strong Microsoft's hold on the market is.

Steven.

In my experience most people who go out of their way to say a language is bad haven't used it much. I was slagging off PHP on some forums a few weeks ago. Have I ever used it? No. But seriously, that a languages implementation is not as fast as it could be of course doesn't mean the language itself is bad. The Unununium team choose to build an OS with Python. Their attitude was, sooner or later someone will come out with a faster implementation. I expect this will be true for Java.

Steven.

It reminds me of that Indecent Proposal film, where a billionaire offers another man $1 million to "borrow" his wife for a night. I know, objectifying women is bad :rolleyes: . Still, I just can't see someone indecently proposing a PS3 for someones wife. Sounds like a recipe for getting a slap :lol: .

Steven.

Hello everyone and welcome to the next episode of Mushy-pea's blog. This entry is about my favourite language (except English of course) Perl. If you're a regular Perl user you might already know this; the developers of Perl 6 are using a prototype version of the Perl 6 interpreter written in Haskell to do various "proof of principle" testing. It's called Pugs (maybe a pun on the Haskell interpreter Hugs). However, the developers' website ( http://dev.perl.org/perl6 ) states that a parallel project called Parrot is the "final target for the Perl 6 interpreter".

Parrot is written in C and does sound quite cool, as its designed to compile various languages (including Perl 6, Tcl, Javascript, Ruby, Lua, Scheme, Python and PHP) into a common bytecode. It is also a virtual machine that can run this bytecode. Sounds a bit like an open source equivalent to .NET really. Oh, that reminds me, it also has a .NET bytecode translator. Are you impressed yet?

But my question is, why not stick with Haskell as the development language for the production Perl 6 interpreter? I don't have anything against C, except that it seems to be used for building all and sundry. If the developers have found that another language provides a usefull platform for development, why not be diverse and stick with it? I know some might say that C allows the most portable programs to be written, but I think this can be true of various languages …

Yes, quite worrying for sure. My advice to those wanting a decent browser is: dump IE and Firefox and use Opera. Don't tend to hear much talk about security holes in that do you?

The three main BSDs (Net, Open and Free) each have about 6 options for how to install the system. The more interesting of these are:

1. Floppy
2. Local filesystem
3. FTP

An installation from floppy is only for the determined. It takes two boot disks to start the installer and about 20 disks to hold the base set and kernel. The other two options sound a bit more usefull.

I agree. BSD is definitely better than Linsux. I just installed netBSD 3.1 on an old PII with 64 MB RAM today. Got the Xwindows desktop going easily. I tried to run X on Slax Linux a few weeks ago on the same machine and it was like "Arrrggg?!? Not enough memory, I'm going to crash now!". Also, netBSD has a translation layer that (is supposed to) let you run other BSD and Linux apps with no hassle. I don't know why people bother with the penguin so much.

My physics reading has slowed down somewhat since I finished my degree, I must admit. I think the last popular science book I dipped into was the sequel to "A Brief History...." (Hawking). I prefer magazine articles mostly as you always get really up to date stuff.

Hello blog readers. So I was thinking, "how can I seriously depress the lovely Daniweb visitors today?". Then it hit me: The End of All Life (EAL). I was reading an article in Physics World a few years ago about some predictions on the long term survival prospects of life, based on known physics. The most important point made regarded the expansion of the universe. A major survey of supernova explosions over the visible history of the universe (surprisingly) seemed to show that this expansion has been accelerating for a long time.

The suggested reasons for this are another story in themself. Now, consider an advanced civilisation. Their home star has run out of fuel and died and to avoid the same fate they must travel the universe in search of more energy (or they will freeze, or starve, or both). To cut off the hopeful sounding "but an advanced species would have bases near many stars", let me say this: all stars will eventually come to a cold, tragic end. GAME OVER already then? Perhaps not.

It is believed that as many as half of all stars may end up as black holes. Current physics suggests that the matter (and hence energy) of the dead star inside a black hole may escape to the surrounding space, albeit at a very slow rate inversely proportional to the star's mass. The energy actually comes from the vacuum just outside the event horizon and it's release causes an equivalent reduction …

Have you considered the possibility that it was diliberate on the part of the "Mc". I would imagine you've heard somthing about this:

http://www.alwayson-network.com/comments.php?id=12929_0_40_0_C

Good article by the way.

Steven.

I was in a pub in Manchester recently for my friend Chris's leaving do (he's got a job in Spain :p ). Somehow a brief discussion about Mac OS X got started (yes, OK I started it). Most people I've met who've used it seem to think it's great because:

1. The GUI is great.
2. It's really reliable.

This issue of reliability and security is a big one in the IT scene. Most users, especially those managing large corporate IT systems, would like an operating system to be virus and hacker proof. Being uncrashable would be a bonus as well.

Thinking about these issues reminded me of the Airbus A320. As you may know, it is too aerodynamically unstable to be flown directly by humans. The pilot operates the controls and a computer interprets these "suggestions" about how the plane should be flying. It does some very complicated maths and works out how to fly the plane safely. However, there are actually four computers doing this job simultaneously. Each one has a different hardware architechture made by a different manufacturer, with a different operating system from a different developer running each machine. The same goes for the flight control software. A failure in one machine should instantly trigger the switching of control to the next one.

This design was chosen to minimise the horrific chance that a computer crash would cause a....CRASH. It seems that many companies choose one OS for a particular application …

With all the disscussion about classical computing issues on Daniweb, I thought it was time for an explanation of quantum computing. As I'm sure most of you are aware, a conventional CPU performs operations by switching transistors on and off in order to manipulate values stored on registers. The registors are of course collections of transistors themselves. Most of the groundwork needed to develop the transistor required an understanding of quantum mechanics, in order to understand how electrons behave on small distance scales in semiconductors.

What quantum mechanics says about electrons is that on small scales they behave more like waves than particles. By small scales I am referring to distances comparable to the width of atoms. This wave like behavior can include commonly understood effects like diffraction, refraction and interference. It also includes a rather less well understood concept called entanglement. Quantum entanglement basically means that once two particles (or waves) have interacted in a particular way, they will behave as if they are a single system across which information can propagate instantaneously.

Some people might say "Doesn't this violate relativity?". The answer is "Kind of. Research the EPR paradox if you're interested.". Anyway, how do you build a quantum computer? First, put a few atoms close together to use as your quantum bits (qbits). This is your computers "register". Then, cool the system to under 1K (-273 C) and entangle the atom's electrons (making sure they stay entangled for a while). This last step is extremely …

Well, I asked Dani and she said I could create a Haskell catagory in code snippits just by submitting a Haskell program :p . What self respecting code repository would be without one? So here goes, this program calculates the nth triangular number, given n by the user.

Steven.

This snippit is a follow up to my first snippit, namely "Simple website hit counter" which is written in Perl. It does exactly the same thing using PHP. "Boring", you might say? Well, I have my reasons for wanting to learn this language and one needs to start somewhere :) . Also, it will give me a chance to compare how the two languages work for samll programs. If you want to make the counter work on your website you can grab the number tiles from my home page if you like (from the root URL load [0-9]tile.gif). Enjoy.

Steven.

Yes, good point.

This is my first working perl script that does anything useful; that being to count the hits made on a web page and display the count graphically. To make the counter work on your web page (should you wish to), you will need to create images for the number tiles like the one found on my site. You will also need to set up a text file containing the starting hit count in the form "1\n2\n3\n4".

You forget one or maybe two things...

Yes, you are quite right. Humans are too greedy and power hungry for such a system to not become corrupt and oppressive. What a shame, hey?

Steven.

But what happened to our thread starter, Mushy-pea? Many of us have addressed your question. Wouldn’t you like to come back into the discussion? :icon_smile:

I`ve been a bit busy recently, adding value to goods and services in Japan. However, I will address a few points. On the question of what is defined as market capitalism (raised by jephthah), I was refering to a market on which capital instruments are traded. By this I mean equities (shares in companies) and bonds (tradable packets of debt).

The problem I see is basically that the individuals and institutions that invest money in these markets want to get a positive return on it (i.e. their money back later plus interest / appreciation). Imagine an investment firm has a large and diverse portfolio of stocks called "A". Suppose that the market value of "A" (plus accrued dividend and interest payments) increases over a substancial period of time, lets says three years. The probability is high that the average GDP of the countries where the stock is floated will have increased.

The more diverse the portfolio (i.e. the more companies it`s investments include), the more chance this is true. The converse of this is that if the average GDP in question remains stable or decreases, there is a high chance that "A" will lose money or gain nothing. Of course, "A" can make a profit for it`s investors even with zero market value growth through dividends and interest payments. However, the way the …

Hi everyone. Now, I`m sure that by now most of you are pretty tired of hearing the world`s politicians blaming everyone they can think of for the financial crisis, but....bear with me. My argument is that capitalism (in it`s current form) is unsustainable in the long term because it requires perpetual economic growth to remain stable. I believe that even if the current crisis had not occured, there would eventually be a greater crisis: saturation.

We would reach the point where everyone in the world had five cars, ten televisions, six computers etc. A point where the consumer could not consume any faster and economic growth became impossible. I think we should just bite the bullet and go communist now. Sure, it might feel harder in the short term, but I think we would reap the benefits eventually. What do people think?

P.S.: The above opinion is one I held before the recent economic downturn. This post is not simply an attempt to provoke reactions for the fun of it.

Steven.

Result:

When you open your eyes again it feels like a inordinately long span of time has passed, almost as long as it was since the last post in this thread. You find yourself in a place of seemlingly complete whiteness. You can`t even see the ground you`re standing on, as it`s no less white than everything else you`re looking at. Then, you turn around and notice a cuboid shaped grey stone building with a wooden door in it about 10 metres away.

Almost immediately, the door opens and a woman in a red dress with dark hair walks calmly out of it towards you. She has a slight smile on her face, which helps to mitigate your initial apprehension. "Traveller, you are well come. I am Kana, the Guardian of the Exit.". You notice that there is something subtley odd about her face, as if it contains the influences of too many ethnic groups to be possible. Nevertheless, you think she`s pretty cute.

"Nice to meet you," you say awkwardly. "Indeed and the same back." she smiles pleasantly. "I can offer you two choices. You may either leave hell now or stay forever. I caution you though, if you leave you will never be able to return.". How do you answer?

A: I`ll leave now, thanks.
B: Actually, I think I`d like to stay.
C: I think I`ll stay. Err, by the way, are you busy tonight?

Steven.

Perhaps a worse fate is to survive for so long that we become weary of our own existance and long for it to end. Forever is a long time.

Steven.

Hi. You are certainly correct in saying that even at 0 K a quantum system still contains energy. However, a quantum system in it`s ground state cannot emit any energy because the ground state is defined as the lowest possible energy state of the system. All it can do is wait around to see if it is able to absorb some energy. The emission of photons can be considered the emission of vibrations in the electromagnetic field. Here we have a system that does not emit vibrations of this kind and, as far as I know, could not emit vibrations of any kind. I warrant that the original point has been disproven.

Steven.