Am 20.08.2011 16:56, schrieb Darren New:
> Yep. How much of your networking isn't connection oriented? Here's a
> hint: all networking is connection oriented. IP layers
> non-connection-oriented networking on top of that, and then layers TCP
> to turn it back into connection-oriented, poorly. If IP wasn't
> connection oriented, you wouldn't need routing tables on each machine.

Nonsense. There's no connection-oriented networking in the classic 
Ethernet, for instance - and IP ran fine on it. It's only the newer 
Ethernet incarnations that installed connection-oriented principles 
below IP, due to operating on point-to-point connections on the physical 
layer. (Which again shows that, as you already mentioned, having 
connection-oriented principles rooted pretty deep in the network stack 
seems to have /some/ benefits.)

You /might/ consider the current route through the internet a kind of 
IP-layer connection, but given that it can change even from packet to 
packet, and the packets can reach the receiver in arbitrary order, I'd 
call that pretty far-fetched.

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Am 20.08.2011 12:49, schrieb Orchid XP v8:

> Can you imagine anything more MIND-NUMBINGLY BORING than staring at a
> sheet of 40 long division problems? YES, I GET IT! I KNOW HOW LONG
> DIVISION WORKS! STOP BUGGING ME ALREADY! >_<
>
> Seriously. If you know how it works, do you really need to do it 200
> times over just to *prove* that you know how it works? It's not even

It's called "training", and is intended to (1) identify and iron out any 
occasional glitches, and (2) empower you to do it without needing to 
think about.

For *proving* that you know the procedure you have the so-called "tests".

> like it's particularly important to be able to *do* long division; it
> isn't something you're going to need to do every day of your adult life.
> You just need to have a firm grasp of /how/ it works and /why/ it works.
> Once you've got that, practising it on endless question sheets is just
> an utter waste of time.

Yes, but instead of a firm grasp of /how/ and /why/ it works, some 
people (and I guess they're the majority) need training to get a firm 
grasp of /how to/ actually do it - either because they never will get a 
firm enough grasp of the /how/ and /why/, or because they just don't 
give a shit.

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Am 20.08.2011 14:30, schrieb Orchid XP v8:
>>> Seriously. If you know how it works, do you really need to do it 200
>>> times over just to *prove* that you know how it works?
>>
>> Wrong, it's not to prove that it works. It is to drum into your "thick
>> little head" how to do it with out thinking. Compare it to repeating a
>> dance step until your body does not think of the individual moves. Then
>> you can build on it.
>
> Doing arithmetic "without thinking" is how we ended up with Verizon Math
> Fail.

The trick is to do the thinking part on such smart questions as "is that 
cents or dollars?", rather than on such boring arithmetical questions as 
"how much is 1 divided by 100?".

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Am 20.08.2011 20:05, schrieb Orchid XP v8:
> Admittedly it was a school for mentally retarded people such as myself...

I don't know the background of that diagnosis, but - fun fact: A lot of 
highly intelligent people are diagnosed as stupid and poor learners, for 
no other reason than them getting bored by the stuff they try to teach 
the normal people.

>>> Can you imagine anything more MIND-NUMBINGLY BORING than staring at a
>>> sheet
>>> of 40 long division problems? YES, I GET IT! I KNOW HOW LONG DIVISION
>>> WORKS!
>>> STOP BUGGING ME ALREADY! >_<
>>
>> You realize that most people aren't that smart, right?
>
> Pro tip: If I can answer 20 long-division questions correctly, I can
> probably answer 2,000 long-division question correctly. It'll just take
> me 100 times longer. :-P Thus, there's no real point to actually
> *making* me answer 2,000 questions...

Yes, but if you (ok, well, some other poor sod) can answer only 10 out 
of 20 long-division questions correctly, then doing 2000 of them might 
help to push that ratio to maybe 19 out of 20.

And because even maths teachers don't usually base their way of teaching 
on stochastical methods, they'll just let every pupil do the 2000.

> I was just having a chuckle about my science teacher whining about how I
> "don't apply myself" in class. His final comment was "more effort
> required". I notice he was the only teacher who forgot to actually fill
> out the performance ratings in the school report. MORE EFFORT REQUIRED! :-P
>
> This amuses me, of course, because I got a B grade for my science, a
> grade which is apparently unprecedented in the history of the school.
> Yeah, I really need to "apply myself" more. :-P Self-important idiot of
> a teacher...

Heh, maybe he only tried to keep up the morale of the other pupils.

"Why do we have to do all the homework when Andrew doesn't?"

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On 8/20/2011 17:38, clipka wrote:
> Nonsense. There's no connection-oriented networking in the classic Ethernet,

What machines does the broadcast address connect to? Guess what? That's what 
they're connected to.

That's the sort of connection I'm talking about, which is important for 
management and maintenance and routing. Indeed, the lack of management 
features is exactly why people went to star topology ethernet, precisely 
because ethernet, like IP, wasn't really connection oriented in that sense, 
and when something broke (like beaconing or disconnecting), it was 
impossible to isolate and diagnose.

Now, of course, IP treats each ethernet network as something separate from 
the routers that link to other ethernet networks. IP isn't really needed if 
you run over ethernet without routers.

I'll grant that IP also runs over non-CO networks like alohanet. Other than 
that, there's a pretty clear idea of whether you're connected or not to 
adjacent machines. IP also isn't needed if you run your network over alohanet.

> You /might/ consider the current route through the internet a kind of
> IP-layer connection,

I believe you misread me. I'm saying IP layers non-connection-oriented on 
top of network connections. I don't need to explain how IP can be 
interpreted as connection-oriented, because I'm saying IP makes 
connection-oriented networks non-connection-oriented.

> but given that it can change even from packet to
> packet, and the packets can reach the receiver in arbitrary order, I'd call
> that pretty far-fetched.

But in practice, it generally doesn't. That's why things like path MTU work. 
However, you're reading me in the wrong direction. IP takes something 
connection-oriented (dial-up, star topology ethernet, etc) and turns it into 
non-connection-oriented. And then layers on top of IP are almost invariably 
used to turn it back into a connection-oriented conversation. The most 
commonly used reason to not have something connection-oriented is that IP 
drops packets and you can't reliably know it happened. I.e., the reason to 
use UPD instead of TCP is often that the underlying IP has made the 
connection unreliable (non-reservation, etc) compared to something that's 
actually connection-oriented.

-- 
Darren New, San Diego CA, USA (PST)
   How come I never get only one kudo?

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Le 21/08/2011 06:03, Darren New nous fit lire :
> I believe you misread me.

I believe you have an issue of vocabulary.
Below IP is not a network (in IT terminology), but links.

Links can be connection-oriented or connectionless.
They can be point to point (like current rj45/c8p8 cables) or they can
be broadcasting media (like 10base5 and other ethernet coaxial cable).
They can even be multipoint (like ISDN and X.25).

The fact that most transmission occurs using TCP should not hide that
there is some other transport protocols above IP which do have their own
interest.

TCP is reliable and ordered. So it is often used.
But there is application who do not care about reliability and order
(such as video distribution: better skip a frame than freezing. same
goes for VoIP: delivery in time is more important; Such application then
use RTP, a protocol above UDP/IP (or when possible, directly above ATM)).

TCP covers 95% of applications, but there is more than TCP under the sun.

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>> Pro tip: If I can answer 20 long-division questions correctly, I can
>> probably answer 2,000 long-division question correctly. It'll just take
>> me 100 times longer. :-P Thus, there's no real point to actually
>> *making* me answer 2,000 questions...
>
> Yes, but if you (ok, well, some other poor sod) can answer only 10 out
> of 20 long-division questions correctly, then doing 2000 of them might
> help to push that ratio to maybe 19 out of 20.
>
> And because even maths teachers don't usually base their way of teaching
> on stochastical methods, they'll just let every pupil do the 2000.

More like "it keeps the students quiet so we don't have to think up any 
*real* tasks for them to do".

>> I was just having a chuckle about my science teacher whining about how I
>> "don't apply myself" in class. His final comment was "more effort
>> required". I notice he was the only teacher who forgot to actually fill
>> out the performance ratings in the school report. MORE EFFORT
>> REQUIRED! :-P
>>
>> This amuses me, of course, because I got a B grade for my science, a
>> grade which is apparently unprecedented in the history of the school.
>> Yeah, I really need to "apply myself" more. :-P Self-important idiot of
>> a teacher...
>
> Heh, maybe he only tried to keep up the morale of the other pupils.
>
> "Why do we have to do all the homework when Andrew doesn't?"

No, he told everybody they were doing really badly, regardless of how 
good or bad their work was.

And when I went over and told him I got a B, he was all like "see, I 
always said you'd do well". NO YOU DIDN'T! You told me I would likely 
fail! "I only said that to motivate you." WTF? Telling people they're 
hopeless is NOT MOTIVATION!

Self-important dick... Man, everybody hated that guy.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On 21/08/2011 10:37 AM, Orchid XP v8 wrote:
> And when I went over and told him I got a B, he was all like "see, I
> always said you'd do well". NO YOU DIDN'T! You told me I would likely
> fail! "I only said that to motivate you." WTF? Telling people they're
> hopeless is NOT MOTIVATION!
>
> Self-important dick... Man, everybody hated that guy.

Recurring dream: Going back in time to school with the knowledge and 
confidence I have now. But then I would probably see what sad examples 
of humanity the male teachers were and give up in disgust.
At least you probably weren't belted (beaten with a leather belt).

-- 
Regards
     Stephen

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>> What part of
>>
>> | U x V | = |U| * |V| * cos a
>>
>> do you *not* understand? :-P

> Would be a lot simpler if the damn stuff you have to use it in
> "understood" all that shit, natively. The problem I always run into is
> that you can find a perfectly comprehensible form of something some
> place, but it is only applicable is you a) do it by hand, or b) know how
> to derive some completely bloody different set of equations, that the
> damn computer will understand. Its like knowing, sort of, how to speak
> some obscure Chinese dialect, but then finding out that you need to
> *write* the information down in German, which for which the only work
> you know is the one applying to yourself, Dummkopf.
>
> Well, not exactly the same case, but if you don't have all the other
> stuff in between the two concepts, understanding what the math is doing
> in the "human" version won't get you any closer to understanding how the
> hell the computer needs to deal with it.

I'm having difficulty following what you're trying to say here.

> The original post in this, describing deriving the two equations needed
> for Mandelbrot, from the original non-computer usable one, is a perfect
> example. My reaction is, "Show the math, step by step, because WTF?" lol

Yeah. All the textbooks advanced enough to talk about complex dynamical 
systems assume that you *already* know everything there is to know about 
complex numbers (a much less advanced topic, comparatively speaking).

The first equation *is* useable in some software packages. But usually 
you need to expand out the real and imaginary parts seperately - a step 
which isn't mentioned anywhere and isn't described in any detail because 
it's presumed to be "obvious".



I assume that was a rhetorical question, but I'll answer anyway...

Start with Z^2 + C. Assume that Z = X + Y i, and C = A + B i. For that 
is what complex numbers are: a real part, and an imaginary part. 
(Explaining *that* is a whole /other/ essay...)

Substituting into the original formula, we have

   (X + Y i)^2 + (A + B i)

We can open the second pair of brackets without changing anything:

   (X + Y i)^2 + A + B i

Now, the first pair of brackets. The binomial theorem tells us the 
answer in canned form, but it's perfectly easy to do it all by hand. 
Since K^2 means the same thing as K * K, we can say

   (X + Y i) (X + Y i) + A + B i

Opening the first pair of brackets, we have

   X (X + Y i) + Y i (X + Y i) + A + B i

Opening the first pair of brackets, we get

   X X + X Y i + Y i (X + Y i) + A + B i

Obviously X X becomes X^2:

   X^2 + X Y i + Y i (X + Y i) + A + B i

Do the same sort of thing with the last pair of brackets:

   X^2 + X Y i + Y i X + Y i Y i + A + B i

The Y i X term is of course the same thing as X Y i:

   X^2 + X Y i + X Y i + Y i Y i + A + B i

Since there are two X Y i terms, we can gather them together:

   X^2 + 2 X Y i + Y i Y i + A + B i

The Y i Y i term is the same thing as Y Y i i. And that's obviously the 
same as Y^2 i^2. Now, BY DEFINITION, i^2 = -1. And Y^2 * -1 = -Y^2. So 
we have

   X^2 + 2 X Y i - Y^2 + A + B i

If we now put all the terms containing "i" into one pair of brackets, 
and everybody else in other pair of brackets, we get

   (X^2 - Y^2 + A) + (2 X Y i + B i)

This is still the same formula, we've just added some redundant brackets 
and rearranged the order a bit. Now, if we take everything in the left 
set of brackets and divide through i, we get

   (X^2 - Y^2 + A) + (2 X Y + B) i

This is still the same formula. (If we open the brackets, we get back 
what we had a few lines ago.) But now we have two purely real 
subexpressions, which a computer can calculate:

   X := X^2 - Y^2 + A
   Y := 2 X Y + B

QED.



I saw pictures in books of the "cubic Mandelbrot", and tried all sorts 
of modifications of the formula to make it cubic instead of quadratic. 
Of course, I didn't know about the binomial theorem yet. In order to get 
a cubic, you need to do this:

   (X + Yi)^3 + (A + Bi)
   (X + Yi)(X + Yi)(X + Yi) + A + Bi
   X(X + Yi)(X + Yi) + Yi(X + Yi)(X + Yi) + A + Bi
   X^2(X + Yi) + XYi(X + Yi) + Yi(X + Yi)(X + Yi) + A + Bi
   X^3 + X^2 Yi + XYi(X + Yi) + Yi(X + Yi)(X + Yi) + A + Bi
   X^3 + X^2 Yi + X^2 Yi + X Y^2 i^2 + Yi(X + Yi)(X + Yi) + A + Bi
   X^3 + X^2 Yi + X^2 Yi - X Y^2 + Yi(X + Yi)(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + Yi(X + Yi)(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + XYi(X + Yi) + Y^2 i^2(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + XYi(X + Yi) - Y^2(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + X^2 Yi + X Y^2 i^2 - Y^2(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + X^2 Yi - X Y^2 - Y^2(X + Yi) + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + X^2 Yi - X Y^2 - X Y^2 + Y^2 i + A + Bi
   X^3 + 2X^2 Yi - X Y^2 + X^2 Yi - 2 X Y^2 + Y^2 i + A + Bi
   X^3 + 2X^2 Yi - 3 X Y^2 + X^2 Yi + Y^2 i + A + Bi
   X^3 + 3X^2 Yi - 3 X Y^2 + Y^2 i + A + Bi
   (X^3 - 3 X Y^2 + A) + (3 X^2 Y i + + Y^2 i + Bi)
   (X^3 - 3 X Y^2 + A) + (3 X^2 Y + Y^2 + B)i

   X := X^3 - 3 X Y^2 + A
   Y := 3 X^2 Y + Y^2 + B

As you can see, the result looks *nothing like* the quadratic case. If 
you didn't know what the derivation procedure was, you would have no 
idea why this is so.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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>> Can you imagine anything more MIND-NUMBINGLY BORING than staring at a
>> sheet of 40 long division problems? YES, I GET IT! I KNOW HOW LONG
>> DIVISION WORKS! STOP BUGGING ME ALREADY! >_<
>>
> Uh, no. The reason you have to do sheet after sheet of utter bullshit
> like that was because your school, like mine, catered to the one idiot
> in the room that didn't grasp the idea after the first 3 times.

That still doesn't make sense. We each got given a textbook. We each 
work through that textbook as quickly or slowly as we please. (Although 
if you're too slow, you get yelled at.) If you get too much stuff wrong, 
they make you redo it, or redo something from a similar textbook.

Which should *still* mean that you only have to do 2,000 questions if 
you're actually that slow at getting it. But noooo...

When math is treated as some kind of punishment, why is anybody 
surprised that nobody wants to do it?

> I refused to do any more of them, they sent me to a school psychologist,
> where they then jumped to several screwed up conclusions, based on, of
> all things, the fact that crayons got handed out alphabetically, so I
> always ended up with the black one (they later adjusted this so people
> got the chance to use other colors, but one wonders how many others
> where misdiagnosed with some sort of disorder over that silly thing),
> and my house **actually** had boxes around the trees and windows, so I
> was "disturbed", because I, "drew boxes around things and used black to
> do it". By the time the idiots figured out that the real problem was
> that I was bored to death of the crap they kept handing me to do, they
> had managed to put me a whole year behind in math. Luckily, I was like
> 6-7 years *ahead* in reading. lol

Did you just say "the education system is fundamentally broken"?

I remember seeing a psychologist. Part of the conversation went like this:

"What were you thinking about just now?"
"Crystals."
"OK. Tell me about crystals."
"Nah, you wouldn't really be interested. I can tell."
"How can you tell?"
"The frames of your glasses are grey."

Now, considering I was, like, 9 years old, most people would have just 
laughed that off. This guy looked actually terrified that I was able to 
READ HIS MIND just by the colour of his glasses. Literally, he was 
desperately trying to figure out how I knew. Obviously, I didn't "know" 
anything. I was just being daft.

It's like nerd-sniping. http://xkcd.com/356/ Apparently psychologists 
are really, *really* easy to confuse.

>> I was always quite bad at arithmetic. I still am. The difference is that
>> today, I use a frigging *computer* to do the work for me. :-P My job is
>> to figure out what the actual calculation is; the computer does the
>> mundane work of actually *running* it.
>>
> Yeah. Same here, more or less. I can't do math in my head worth shit,
> and I hate doing it by hand on paper.

I find doing /arithmetic/ on paper to be trivially easy. It's just not 
particularly interesting. I quite often do /math/ on paper - mainly due 
to the difficulty of typing most of the notation on a computer.

> Shortcuts would help, but you don't get those in school.

I haven't been to school in a long time. I hear they no longer teach 
"mathematics". They teach "numeracy". And it doesn't involve knowing how 
to add and subtract and multiply and divide. They only teach you how to 
/estimate/ results.

I have no idea whether this is true, or just what the media tells us.

>> I spent almost all of my time at
>> college sat in the library, absorbing everything I could lay my hands on.
>>
> Should probably do that myself. The problem is figuring out where the
> hell my gaps are to start with, then finding something that doesn't bore
> the hell out of me reading it

My problem is that I know a lot of quite advanced (i.e., interesting) 
mathematics, but I don't know some of the stuff that comes before that. 
Normally you would learn the simple stuff first, gradually moving on to 
the more advanced stuff. Which means there are books full of simple 
stuff, and books full of advanced stuff. And to fill the gaps in my 
knowledge, I'd have to read one of the "introductory" books where I 
already know 95% of what it says, just to learn the 5% that I haven't 
stumbled across yet.

> like, I don't know, something directed at
> "application" of the math, not just how the hell you write the
> equations. I think this is a huge damn failing in "text books", and
> classes in general. Its one thing to hand someone a formula, or even a
> stupidly simply thing you want someone to do, like graphing a line, but
> give no possible context for why the hell anyone would bother to do so,
> save maybe some historical context. Its quite a bit different when you
> "need" to know, for your own purposes, how thick a rope will get, wound
> onto a spindle, and thus how big the spindle needs to be, versus just
> having someone hand you a problem, and ask you to give them a result,
> when your only thought is likely to be, "Why the hell do I need this?"
> Mind, that was physics class, while the normal math classes don't even
> give you problems that come even remotely close to that interesting. In
> any case, I don't remember the equations. lol

It depends.

Sometimes I just want to solve a specific problem. But I do also enjoy 
reading about mathematical objects and their properties just for the 
hell of doing so. It's interesting. (I suspect if you had to do this for 
an actual *test*, it would become much less interesting...) For example, 
reading about polynomials and all the patterns and symmetries they have. 
And /then/, when you find yourself needing to solve some problem that 
happens to involve polynomials, you already know quite a bit about them, 
and therefore where to start looking for a solution.

> Nah.. Stupidity desirable? How could that ever be the case. I mean, its
> not like, at least in the US, there are politicians banking on it,
> products sold based on playing fast and loose with as little information
> as possible, or active attempts to undermine education. That is just
> absurd! Or, in reality, as I put it a bit ago when talking about the US
> version of libertarianism - "The concept is simple, lower taxes,
> resulting in poorer schools, resulting in closed schools, and since its
> everyone's 'right' to choose to be ignorant, the fact that 90% of the
> population is stupid has nothing to do with the failure of the system,
> its entirely the fault of people not moving to where the only two
> schools still open are located."

WOW. O_O

> Dear old Madison would be having a
> heart attack at this shit, if he hadn't had the sad misfortune of dying
> in 1836.

...irony...

> I seems only fitting that by 2036 the US might be so fucking stupid that
> they couldn't build a log cabin from his time, let alone work out why
> living in one would be preferable to huddling under a tree, or wearing
> animal skins in a cave... Or, so it sometimes seems the trajectory of
> some of this stupid shit is headed.

I think sometimes it's hard to tell whether the entire world is stupid, 
or just a vocal minority.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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