Evolution of Technology based on Trivial Circumsta

Posted by: SE_Sport_Driver

Evolution of Technology based on Trivial Circumsta - 27/03/2002 13:07

Has anyone here heard the story on how the US railways are all the width they are because of Roman chariots (or something like that)? I can't find any information on it, but I remember seeing a show where they said that the railway systems of the past were all different widths - and because of this, were incompatible. When a standard was agreed upon, they went with today's standard width. I'm not sure if this was chosen because on manufactuer was more influencial or not... But it all came down to how there were roads made by the Romans that were a certain width. These roads developed ruts and later builders of cars or whatever had to build to the same wheelbase inorder to fit these ruts. When locomotives were made, it was easier to just use existing tooling. So.... long story short (too late) today's railways are as wide as they are today because of some dude in Itay years and years ago. (I will try to find a link or something, but I saw this on some PBS show years ago).

I was wondering if any of you knew any other little stories like that. I know that the memory structure on current PC's is still based on PC's from the 80's, but I don't really know how the original figure was reached.

Another little story is how US NTSC (Never The Same Color ) television uses 60 fields (or 30 frames) per second. This was becuase of the US's power system being 120volts AC. The power basically became the timeing device. Someone determined that all humans really need is 45 fields per second to similate a moving image, so the 60 is really over kill and a waste of information. Needing to put out 30 frames per second, NTSC had to sacrifice scan lines per frame. In contrast, PAL uses fewer frames per second (but still enough) but allow for more scan lines. Because of this, PAL has always been considered to be better than NTSC. So it is interesting that the first TV makers in the US were not limited by their own means, but by Edison for picking the number 120. It would be interesting to go back and find out "why 120?"

This is all from the top of my head, so feel free to correct me.
Posted by: morrisdl

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 13:18

Why the Space shuttle SRBs are 2 horses arse wide...

http://www.paulperry.net/notes/standard_guage.asp
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 14:43

Yeah, I thought that story sounded a bit like an urban legend. Interesting summary, thanks for the link, Morris.
Posted by: tman

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 21:49

This site has actually gone and researched this urban legend and said it was false Quite an interesting site if you've got an hour or so free to have a look around.

The PC standard is really crap in my opinion. It's had features and other parts grafted on over the years. ACPI and PNP are good examples of recent braindeadness at work. ACPI needs a huge interpreter in the kernel just to handle initialising the hardware and PNP is great if it works. Totally crap if it decides not to. Give me back the days of jumper blocks
I'm not saying that the original hardware was any better though. IBM didn't actually follow the specifications laid out by Intel and redefined the meaning several of the interrupts. Don't get me started about the A20 line gate inside the keyboard controller...

On a related note, Bill Gates denies ever saying that 640k would be enough for anybody. He was interviewed awhile back here and he does give a quite convincing reason.

The mains voltage doesn't matter for the television standards. It's the frequency that is important. US electricity is at 60hz whilst Europe is mostly 50hz. The reason why the television standards used mains frequency is that it is quite stable as the power station actually has extra equipment to lock it to 50 or 60 hertz. If the mains frequency is a multiple of picture field scan rate then interference is also reduced.

- Trevor
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 22:08

I've just dealt with ACPI for the first time and I thought it was great. Given, this was under Linux, so I don't know how braindeadedly Windows handles it. And I once agreed with you about PNP until I used it under Linux. Works like a champ there, and you can decide which IRQs and I/O ports you want it to use. (Were you aware that Microsoft suggests setting your PC BIOS to indicate that the running OS is not PNP-compatible so that the BIOS will pick IRQs, I/O ports, etc?)

Bill Gates may not have said that, but he definitely did say that all encryption will be broken once someone finds a way to easily factor large prime numbers (from ``The Road Ahead'' -- go find it at your bookstore -- it's around page 110 or page 265, depending on the release).
Posted by: tman

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 22:33

ACPI is a good idea in theory but it's been implemented by committee and the standard is huge and extremely convoluted. I just think that using a big binary interpreter to run code in the BIOS in an attempt to achieve portability is a bad way of doing it. I will probably have to either change my mind about it or put up with the idea in the future now the option to disable ACPI has been removed from new BIOS's. How good is the support for ACPI these days? I haven't tried to run it since the early days.

It's just that anytime anybody comes up with a big unified model to handle hardware, somebody else comes along with something that doesn't fit into the model and you need to add a hack.

Ideal world for me would be that everybody at least tried to follow a sane standard and that they published their APIs. Chances of this happening are minimal though Anybody know people at 3Com responsible for writing drivers for their winmodems? I want to use my built-in 56k modem in Linux!

PnP under Linux is a joy to use. PnP under Windows is definately a different experience. I want to be able to specify exactly what the hardware should set itself to. The computer shouldn't always think it knows more than the user

I didn't know that Microsoft recommends setting the PnP OS option in the BIOS to be off. I've always had to set it to off because the USB host controller wouldn't be initialised properly for Linux. In my old VAIO you couldn't even turn it off at all.

Well... There IS an quick way to factor large prime numbers... You just need to make a large quantum computer. They've only done it with a small number of qubits at the moment so your data is safe still for a few years

I'm seriously on a big rant at the moment so I apologise if I come over as being argumentative or plain irritating

- Trevor
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 22:37

My point is that it's already remarkably easy to factor large prime numbers. Given a large prime P, the factors are {P, 1}.

I don't know much about ACPI other than under Linux, I can get signals from each of the ACPI devices (mostly buttons AFAIK), and do whatever I want with them. I just set up a daemon on a computer to ``shutdown -h now'' when the front panel button is pressed 3 times within 5 seconds. Try doing that with APM.
Posted by: genixia

Re: Evolution of Technology based on Trivial Circumsta - 27/03/2002 22:46

Given a large prime P, the factors are {P, 1}.

Given *any* prime P, the factors are (P, 1)

Posted by: tman

Re: Evolution of Technology based on Trivial Circumsta - 28/03/2002 04:51

Just saying that a factor of P is P and 1 isn't quite what they had in mind. Finding the values of the two prime numbers that make up P is much harder as you know

I just tried ACPI on my Inspiron and bizarre and nasty things started to happen. I blame the flakey Dell BIOS

- Trevor
Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circumsta - 28/03/2002 09:21

That really bums me out that it is an urban legend.. Like I said, the post I made was from the top of my head (thanks for clarifying the Frequency thing) but I am remembering more of the original show I saw on PBS. It was a really cool that tied all of these seemingly unrelated objects and events together. The host would be in England current day and say something about Tibet and with a snap of his fingers, he was in Tibet. Must have been a bitch to schedule all of thier shoots! But now I'm wondering how much of that show is real and how much is based on urban myths....
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 10:21

but I am remembering more of the original show I saw on PBS

That would be James Burke's "Connections" series, eh?

You might be able to e-mail Burke and ask him what his source was. Also, there was a companion book to the series that might contain that reference and that you can probably get at your library.

In this vein, my contribution of "trivial foundations" would be -- while Beethoven would be pissed if he heard it called trivial -- the capacity/design of the Compact Disc being based on the length of the 9th Symphony. There are recent techno discussions on the BBS about CD design factors, but I am old enough to remember reading a story before the market introduction of CDs about the Beethoven factor. I just can't find a solid reference to it now.

[edit: It looks like Burke was born in Ulster]
Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 10:33

Jim, I heard that too. The length of the LP may be related too.... interesting.
Posted by: tanstaafl.

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 11:50

the capacity/design of the Compact Disc being based on the length of the 9th Symphony.

Probably not... Most performances of the glorious Ninth run 59--63 minutes, whereas (as you well know) the capacity of the CD is anything from 68--75 minutes, depending on how far the producers want to stretch the standard.

tanstaafl.
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:09

Most performances of the glorious Ninth run 59--63 minutes

It's coming back to me now.....they based it on the famous performance of the 9th by the narcoleptic Russian conductor Somnolensky.

Boy, I've got the bug now. This may be another urban legend, but I do remember reading about it a long time ago. I searched some CD FAQ sites, and a few had pointers to supposed histories (and even reference to this "9th" factoid) but they were a dead end from a truth/provenance standpoint.

More to come...

(edit: Well, I did find another reference to it on urbanlegends.com that cites a book "Ken C. Pohlmann, _The Compact Disc Handbook_, 2nd Ed., 1992 (ISBN 0-89579-301-6)" and goes on to cite the following from that and another source: "Why 74 minutes? Pohlmann doesn't know either. He says: 'According to one version of history, the 74-minute time was selected because conductor Herbert von Karajan, a Polygram artist**, demanded a 74-minute capacity so his favorite piece, Beethoven's _Ninth Symphony_, would fit on a single disc. The other version claims the wife of Sony chairman Akio Morita insisted that Beethoven's _Ninth Symphony_, her favorite piece, fit on a disc.' Neither version is attributed." .....and the same UL page provides another snip from an interview by Nancy Herther in the July 1992 _CD-ROM Professional_ ("The Past, Present and Future of the Compact Disc, Multimedia and the Industry: An Interview with Dr. Toshi Doi"). Dr. Doi is a Director of the Sony Corporation, and helped invent the compact disc. On p. 21:
" Q. I've heard different stories about the beginnings of the compact disc. Could you please tell us how the compact disc came to be the 12 cm disc that it is.
A. Mr. Oga from Sony decided the size of the compact disc. We had a big debate with Philips on the size of the CD disc. I was pushing 10 cm, because it was a round number and a very small disc. Sony was very interested in having a portable CD player from the very beginning. Philips was pushing for a much larger disc***. Mr. Oga finally made the decision that he wanted something which could hold the entire Beethoven's 9th Symphony on a single disc. That was a very good decision and as good of a reason as any other."


The interview actually seems more credible -- unless Doi just enjoys perpetuating a good joke!)

Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:13

Isn't the original CD spec for 74 minutes? I know that in recent years they have stretched it.....??
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:17

Correct, Doug. The CD-length-because-of-the-9th is also an Urban Legend. I'm sure Rob Schofield could chime in on it, since he worked for Philips during that time.

Burke's Connections series was really cool, but I figured that some of the so-called "connections" were rather thin threads and perhaps a little shaky on the historical research. Didn't make the show any less interesting, though, I really enjoyed it.
Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:18

Man! This is like finding out that Santa doesn't exist! :P
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:30

The CD-length-because-of-the-9th is also an Urban Legend

Dang, Tony, you're too quick for me. I added some snips from urbanlegends.com to my earlier post. It made me think that, rather than a confirmed UL, it's still up in the air (and may remain so). Even with the quote from the Sony exec, though, who needs a 74-minute disc spec for a 63 minute symphony?

[edit: Looking at that Toi quote I'm wondering, what would be the time capacity of a disk if they went with the 10cm diameter he refers to? Would it be under 63 minutes? If so, that makes the rationale a little more credible, Beethoven-wise.]
Posted by: svferris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:34

From what I remember learning in a digital music class I took in college, the 74-minute spec was a completely arbitrary number. I heard it was somewhat based on how much data could be fit on the CD and at what type of compression. But, I think I remember someone saying that the minute length could have varied either way.

I'm going to see if I can find the info on this.
Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:37

Maybe they wanted 5" disks so that they could use them in computers? And THAT determined the 74min point?
Posted by: tanstaafl.

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:37

Isn't the original CD spec for 74 minutes? I know that in recent years they have stretched it.....??

Yes, I believe you're right. I got confused (amazing how easily that happens) and pulled the 68 number from the standard capacity of 680 MB. 68 minutes, 680 megabytes, 10,936 square millimeters of surface area -- it's all the same thing, isn't it?

And get this -- a CD is almost exactly one cubic inch in volume.

118mm diameter x 1.5mm thick = 16404 mm^3, = 1.001 in^3.

So, a CD plays at roughly one and a quarter hours per cubic inch. Now that's information that's useful to know!

tanstaafl.
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:38

The amount of data per square inch on a CD is/was fixed. There is no compression. When deciding on the final standard size of the disk, there was a known, fixed ratio trade-off between physical handling size and the amount of music. They simply set the standard size in a place where most of the known "long" recordings would fit, while still offering an easy-to-handle, compact size for the media.

I'm sure that fitting the 9th onto the disc was one of their concerns when making the decision. But it certainly wouldn't have been the only piece they considered.
Posted by: svferris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:42

I think that sounds right, Tony. I remember them mentioning that the size was pretty arbitrary. I suppose when developing anything like this (such as a PDA), you need to keep usability in mind.
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:42

118mm diameter x 1.5mm thick = 16404 mm^3, = 1.001 in^3.

Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:53

Not like it is the authoritative work on the subject, but the full UL page I referred to is here . It does have a little more info about some of the other design/density considerations.

In the end, given the haze of history, I think I'd agree with Tony that the "9th" might have been a factor but was likely not *the* factor as its near-UL status might suggest. That doesn't seem inconsistent with what that gent Doi said.

Also, WRT that whole Von Karajan thing (and maybe Doug has an opinion on this) my memory is that when CDs were *almost* on the market (they were building like a total of 2 pressing plants) it seemed like there was a bigger stake for classical labels -- like who cared what the quality of rock-and-roll records was like, relatively speaking? I could see DG and others having a pretty active lobby at Sony/Philips. Plus, I don't think Von Karajan was known for keeping his mouth shut.

[edit: "Doi", not "Toi". Also, I was thinking H Von Karajan was on Deutsche Grammaphon, but as the UL page points out, it was Polygram that was (still is??) a Philips subsidiary]
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 12:55

No, but a tax should be imposed upon him each time he does

Before I vote please tell me: would the money go to the RIAA? Or does it depend on what he's calculating?
Posted by: davec

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 13:13

Man! This is like finding out that Santa doesn't exist! :P

Guess what? The Easter bunny doesn't anymore either... (See attached)
Posted by: canuckInOR

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 14:19

If you account for the hole in the middle of the CD, would that make the numbers work out exactly?
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 14:25

If you account for the hole in the middle of the CD, would that make the numbers work out exactly?

Oh no, don't get him started.
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 14:27

Guess what? The Easter bunny doesn't anymore either... (See attached)

ROFL
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 17:28

    There is no compression.
Of course there's compression. Unless your ears work at 16-bit 44.1kHz and not analogically. If they'd decided on a 48kHz sampling rate or 24-bit encodings, then the capacity of the disk would change significantly. And, like it or not, that's compression. Lossy compression at that, since you're losing a significant amount of data (16bits is a lot fewer than an infinite number of bits, and a 44.1kHz sample rate is, again, much less than continuousness).
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 17:38

And, like it or not, that's compression.

My response was to this post:

I heard it was somewhat based on how much data could be fit on the CD and at what type of compression.

I realize that from a semantic standpoint, you could argue that different sampling frequencies can be considered "compression", even though that word isn't used (as far as I know) to describe the different data rates resulting from different sampling frequencies.

So I'm assuming that you mean one of the factors they considered when deciding upon the CD format was the sampling frequency and the sampling resolution, because those would also affect the amount of sound you could fit on a disc. All right, I'll give you that.

But my response was based on the current definition of compression as being short for "data compression", and I just wanted to make the point that the data rate of an audio compact disc is fixed, and that there's no "type of compression" on an audio compact disk since it is raw, uncompressed, unencrypted wave sample data.
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 17:48

Since an exact copy of the original data would take an infinite amount of storage, any storage of that same data on a finite storage medium would, by definition, be compression. But whatever.

And that would be raw, uncompressed PCM data, BTW. Don't want anyone to confuse the audio storage format of PCM with the containment system known as WAV (which can contain other audio storage formats). (I realize you said ``wave'' and not ``WAV'', but just to make it perfectly clear....)
Posted by: tman

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 17:53

I believe they reduced the spacing and extended the spiral track out further. I read somewhere recently that they could do this because of better reader hardware and the process for making CDs had improved enough to make the metal deposition quite uniform all the way to the edges. Now, as to where I read this I can't quite remember. Was in the last week or two though...

Don't you just hate it when that happens?

- Trevor
Posted by: tanstaafl.

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 19:30

If you account for the hole in the middle of the CD, would that make the numbers work out exactly?

Naaah... makes it further off. You end up with .9902 in^3.



tanstaafl.
Posted by: pgrzelak

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 19:40

Perhaps the rounded edges of the CD make up that last fraction...

That is one bit of trivia I will have to remember. Perhaps I will even use it someday, under a somewhat bizarre set of circumstances...
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 20:00

I'm going to see if I can find the info on this.

Using "Tosho Doi" in some keyword searches, I found a few items including this (interesting in other respects) article from Stereophile . It's not 100% consistent with Doi's interview answer, but it doesn't contradict it, either -- I could see the Von Karajan theory fitting with the other Sony explanation if, as cited in the footnote, HVK was buddies with a bigwig at Sony.

Here's another spin, but with the only reference being the previously mentioned interview.

Based on the Doi interview and the Stereophile piece, I'm taking it out of my list of ULs.

(edit: Oh, and an interesting digital aside on HVK in some liner notes here .)
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 28/03/2002 20:05

Perhaps the rounded edges of the CD make up that last fraction...

Oh, crap. That's just an *invitation* for Doug to factor in the volume lost outside a half-circle edge of 1.5mm diameter!

If the radius is irregular, we're doomed.
Posted by: ithoughti

Re: Evolution of Technology based on Trivial Circumsta - 29/03/2002 09:14

Ok, here is another one that I have wondered about for a while:

Why do most prices end with .99 or .95? Where did the odd pricing start and why? I know that people will say that things are priced that way because consumers will buy things thinking that $14.99 is less money than $15.00, but I think that I've heard that the odd pricing thing started with another intent. And whats with the 9/10th of a cent tagged on to gasoline prices? That's another one that pisses me off.

Edit:

here is one little bit of explaination that I found. It reads:

Odd-Even Pricing


Many products today are sold at prices with "odd" endings--that is, rather than selling something that $10.00, it is sold at $9.99. Interestingly, the practice was started not so much to deceive consumers, but rather to make sure that dishonest clerks would have to "ring up" a purchase in order to give change. One theory today is that consumers will conceive the $9.99 price as "nine dollars plus 'change'" rather than the effective $10.

Recent research has shown that odd price endings appear to have some modest effects under some circumstances--that is, consumers seem to be influenced a little bit, but not greatly. Interestingly, such effects could not be replicated in Germany, perhaps because of cultural differences.

Odd endings may have significant implications for the positioning of goods. Discount stores tend to use these endings, while upscale department stores often use whole dollar amounts as a sign of quality. While inflation has undoubtedly changed the figures involved, reseach done in the 1980s suggested odd prices were more effective below $7.00, where people often wanted to feel they got a bargain, while diners who paid more than that amount seemed to prefer the assurance of quality implied by a whole figure.


Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circumsta - 29/03/2002 11:41

At Circuit City, they use different numbers of cents to indicate sale conditions. For example, 99 cents might mean normal price, 98 cents might mean clearance, 97 might mean open-box, and 95 might mean sale price. I forget what correlates to what, but it's something like that. Other stores might also use similar systems. On the other hand, I'm sure that that's not the reason it was started, but just abuse of a system that had already been established.

Oh, and if I remember correctly, the nine tenths of a cent on gas prices is part of the gas tax. That is, the gas tax specifies something and nine tenths of a cent per gallon, and the retailers just got used to passing that cost on directly, or some such. (Seems like it would be easier to just overcharge the consumer by one tenth of a cent, but what do I know?)
Posted by: svferris

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 11:55

BTW, I agree with what wfaulk said. I mentioned compression because the sound recorded on current audio CDs is not the actual sound recorded. It's compressed, I believe by chopping out some high and low frequencies (similar to MP3, but significantly less). This is the reason we have the DVD Audio and Super Audio CD formats. They want to fill in all that missing data that had to be cut in order to fit on a regular CD by allowing more data to be fit on these new mediums.
Posted by: svferris

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 12:42

Ok, I think I meant what wfaulk was talking about regarding sampling rates, and not the chopping...

Here's one of the articles I was thinking of, talking about DVD Audio and Super Audio CDs.

http://www.audiorevolution.com/equip/dvdavssacd/index.html
Posted by: eternalsun

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 17:41

You guys are such square thinkers. The outside of the box converse to what you said.

You can store an infinite amount of data using 1 bit of storage.

How?

If you have a infinite amount of data, in a sequence that looks like this:

989563482947562821837372... and so on, you can place one decimal point thus:

9.89563482947562821837372... and then get a scaled storage medium that is marked from 0 to 10 and place 1 mark just below the "10" mark near the 9.8th position. That 1 bit of data represents an infinite amount of information.

And also, you don't need an infinite amount of description to describe the exact copy of the music. It would be finite. Large yes, but finite.

Calvin
Posted by: eternalsun

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 17:44

Hey speaking of CD's... how goes my sun tanned CD's? ;-D

Calvin
Posted by: tanstaafl.

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 18:17

how goes my sun tanned CD's? ;-D

I have officially admitted defeat.

Cleaning the damage caused by the suntan lotion was trivial. However, the CDs were in such bad condition otherwise with deep scratches running radially, and irregular blemishes a quarter inch across that I could not get them to play error free. I was able to get them to where I could rip and encode all the tracks, but some of the tracks still have artifacts and skips.

Oddly, the CDs appear playable now -- I have CDs that look worse that play with no problems. But I cannot make them work perfectly.

tanstaafl.
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circu - 29/03/2002 21:17

I hope you're joking on both of those points.
Posted by: number6

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 02:34

In reply to:


Just saying that a factor of P is P and 1 isn't quite what they had in mind. Finding the values of the two prime numbers that make up P is much harder as you know




Well unless the two (prime) numbers that were multiplied to make P were 1 and P, then the resulting number from this multiplication can *never* be prime.

However what you are saying is that the difficulty of finding quickly large prime (or near-prime) numbers is a major cornerstone of modern cryptographic systems.

So, once a quick way is found to find (also called factoring) such large numbers then this cornerstone is severely weakened.

Its this aspect that Gates (and others) have previously commented on.






Posted by: number6

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 03:21

I've been out of town all week, so I come to this sobject a little later than most but heres some comments:

In reply to:


Another little story is how US NTSC (Never The Same Color ) television uses 60 fields (or 30 frames) per second. This was becuase of the US's power system being 120volts AC. The power basically became the timeing device. Someone determined that all humans really need is 45 fields per second to similate a moving image, so the 60 is really over kill and a waste of information. Needing to put out 30 frames per second, NTSC had to sacrifice scan lines per frame. In contrast, PAL uses fewer frames per second (but still enough) but allow for more scan lines. Because of this, PAL has always been considered to be better than NTSC. So it is interesting that the first TV makers in the US were not limited by their own means, but by Edison for picking the number 120. It would be interesting to go back and find out "why 120?"




PAL is considered superior to NTSC, not just because they lowered the scan rate to 50 fields/second and therefore increased the number of scan lines per field - they did this trade-off to keep the effective 'horizontal' scan rate for both NTSC and PAL the same. Hence a PAL TV set can often receive and display a black and white NTSC signal without problems.

PAL came second (NTSC was the first all-electronic TV scanning system).

Because PAL came second they had the chance to fix some of the defects with NTSC, one major one being the annoying 'loss of colour' signal phase lock, causing the whole screen field to change colour (you know those faces that flash green and back again).

They fixed this problem with PAL by making every other scan line in the field reverse/invert the colour phase signal, thus stopping those 'loss of colour' lock problems affecting all scan lines in the field (worst case it would affect 2 scan lines and the eye will blend such errors making them much less obvious).

This also gave rise to the name for PAL - it stands for something like Phase (alteration) on Alternate Lines (PAL).

the other comment about 60 fields/second, in fact NTSC runs at 59.997 fields/second or something close to stop any mains interference caused by 60Hz mains.

I can't recall why 60Hz is used, I believe Nikola Telsa (who designed the AC systems used in America today)
[Edison invented/pushed DC, Telsa invented just about everything to do with AC, single phase, 3 phase the works], picked 120 volts because it was considered much safer than any other voltage in use at the time [e.g. 200 Volts DC].

However, 60 is a multiple of lots of numbers and has a lot of factors and this fixation with 60 can be traced back to the Sumerians.
These are the guys who gave us 60 seconds a minute. 60 Minutes a hour and 360 degrees in a circle to name some things.

A bigger question is, why do the countries that have 220 Volts AC power use 50 Hertz as their mains voltage frequency and not 60?

I think that the 50/60 hertz relates to how fast the generator sets of the 19th century could be spun to make AC power, at 60 Hertz the set would need to spin at 3600 RPM, at 50 Hertz, 3000 RPM.

Regarding Railway gauges: not everywhere uses the 5 foot 10 or whatever gauge used in the US.

Here in New Zealand we use 3 foot 6 inch as our railway gauge - the reason mainly being that because this is such a rocky/mountainous/geologically active country using a smaller railway gauge meant that the diameter of the tunnels/ width of bridges/embankments/viaducts etc that had to be built could be "smaller" and thus cheaper to build.
So, because of this decision made about 140 years ago we now have a railway system which trains cannot go much above 60 mph without the trains rocking too much.
Hence Railway is not a popular freight or public transport mechanism.
Good call guys.


On a related note, the current QWERTY layout on the keyboard was (carefully) designed to prevent the typists (who used the early typewriter models) from being able to type most of the commonly adjacent letters simultaneously which could cause the keys to jam together in the first typewriters made.
[A problem which was overcome fairly quickly, but by then the QWERTY layout had become common practise].

So the QWERTY layout is in use today to overcome a mechanical design defect of the earliest mechanical typewriters designed to SLOW typists of the day down.
It has been proven that in some cases as straight alphabetical keyboard can be faster to type on than a QWERTY keyboard, but the QWERTY layout is now firmly entrenched.


Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 09:41

Actually, QWERTY was designed to speed typists up, not slow them down. The idea was that the developer of the QWERTY keyboard (I forget his name right now) placed the keys in that order in order to prevent the striking levers from locking together. (If you have an old manual typewriter lying around, you can duplicate this locking.) Before he developed the QWERTY keyboard, typists had to type slowly in order to keep keys from locking together. But by rearranging the keys, he kept the common diads from being placed close together in the striking levers. Since the typists then didn't have to worry about the levers sticking together anymore, they were free to type as fast as they wanted with fewer repercussions.

Oh -- and if you can show me a good study that shows that any particular keyboard is faster than QWERTY, I'd like to see it. (Not to imply that QWERTY is better, but, rather, that none is better than another, at least for just the letters.)

(I know I rambled a little bit there, but I haven't had as much sleep as I'd like.)
Posted by: pgrzelak

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 09:44

Greetings!

I remember hearing that it also involved distributing the most common letters evenly across all of the fingers. This way, you can build better speed. Or so the story went.
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 10:00

Well, there may have been some thought to generally placing the elements of common diads on the opposite sides of the keyboard (that would be one good way to keep the striking levers far apart), but you might be thinking of the Dvorak keyboard. In that arrangement, all of the common English vowels are in the home row under the left hand, and the most common consonants are on the home row under the right hand. Since English words tend to a more-or-less consonant-vowel-consonant rhythm that would tend to make a left-right-left rhythm when typing.

(BTW, the only well-known studies that show that Dvorak's keyboard layout are superior are the ones conducted by Dvorak himself, and he had a financial stake in a venture promoting his keyboards.)
Posted by: tfabris

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 11:29

And before someone asks, in this case "Dvorak" refers to the man who invented that keyboard, NOT the computer columnist who writes for PC Magazine and hosts "Silicon Spin" on ZDTV. Different people. If they're related, it's only distantly.
Posted by: tman

Re: Evolution of Technology based on Trivial Circumsta - 30/03/2002 17:03

It used to be 60hz until they added colour to the signal and then it became 59.94hz. No idea why it is exactly that though

- Trevor
Posted by: drakino

Re: Evolution of Technology based on Trivial Circumsta - 31/03/2002 09:11

At Circuit City, they use different numbers of cents to indicate sale conditions

Best Buy does this as well, and I think 94 means it's on closeout. It's kinda nice to know, because you can see exactly what items they are planning on getting rid of shortly. Having several friends work there has revealed a lot I ddn't need to know about retail stores.
Posted by: eternalsun

Re: Evolution of Technology based on Trivial Circu - 01/04/2002 14:23

I'm convinced the sun screen lotion did in the CD, not the scratches. The scratches were in place before the CD were sun screened, and there was no skipping or errors of any sort until the sun screen got on the CD. ;-)

I don't even recall the brand of sunscreen, think it was most likely Coppertone SPF 40. I think an experiment is in order -- spread Coppertone SPF 40 on a clean CD-R (the effect is the same on CD-R's) and see if it can be reversed. :-D

Doug you can keep the CD's. Thanks for trying :-)

Calvin
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 09:04

Having several friends work there has revealed a lot I ddn't need to know about retail stores.

For a while, a friend was an assistant manager at a bicycle shop here (one of the largest). Their price tags were square fluorescent green stickers (orange for closeout). If you saw a price on something of $99.95, you would also see a number/code up above offset to the right, something like 0005. That was simply the employee discount price (on which they could still make a little money) printed with no decimals in reverse. And, yes, figures of $99.95 - 0005 were typical. 100%+ markup.
Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 09:59

Straying a bit off topic, but I worked at a bike shop for several years. We made almost NO money on bikes (we had pretty low prices, but not super low). But we made a killing on accessories. That is why we would rather throw in a few $10 water bottles and some $12 water bottle holders rather than knock $44 off of the price of the bike. That "$44" that we just "threw in" only cost us maybe $8. On the otherhand, we made at most $50 off a bike. Service was another money maker.
Posted by: ashmoore

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 10:34

OK, another WHY? question.
Why is a 2x4 not?
I know its because of milling etc etc, but why call it a 2x4 when it is NEVER that size.
You can't tell me that it starts out as 2x4 then trimmed down to be straight because the length is a huge factor for that.
Most other engineered lumber is the actual size, 3/4 ply is 3/4 thick.
3/4 MDF is 3/4 even though its pressed into that shape and starts out 3 feet thick, they don't call it 3foot MDF!
Same question for measuring nails in pennies. Has the penny been that size since it was first minted or am I missing something?
I don't think James Burke would cover that.
I did like him in Tomorrows World, yes I am old enough to remember him in that!


Posted by: SE_Sport_Driver

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 10:39

I'm guessing that the 2x4 thing is similar to how all soda is called "coke" in some areas and how all in-line skates are called "rollerblades" (I used to skate for them and they faught this as best they could!!) and how all cotton swabs are called "q-tips" etc.... Older homes DO have 2"x4" 2x4's. I am guessing that there was a gradual change to the new size and that carpenders still refered to them as 2x4's because they used them inplace of what the original 2"x4" versions were used for....

But that is pure guess.
Posted by: jimhogan

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 10:43

On the otherhand, we made at most $50 off a bike.

Yes. When I mentioned markups, I probably should have qualified that. All those green tags were on the sexy lycra tights, Italian shoes, water bottles, etc. People will spend a lot of time price shopping the big stuff, but then get killed on the little bits. Also, I gather that 100% markup is pretty standard stuff for retail lines like clothing -- overall retailers can need those margins to cover the XXS and oddball items that don't move..
Posted by: wfaulk

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 10:47

It is originally cut out of a log as 2" by 4". Much of the size reduction happens in drying the wood. The rest is planed down to make it smoother and to get it to a consistent size. Why it's 1 1/2" by 3 1/2" specifically, I don't know.

Nails are measured that way supposedly because of how much they orginally cost. There are a number of theories, but they are all quite similar. One is that it cost 10 pennies (which was abbreviated at the time as `d' for `denarius') for a hundred, or 10d for a thousand, or a pound.

Speaking of British pennies, when did they stop being abbreviated as `d'? When you guys went from your old monetary system to the new decimal system (that was about 1965, right?)? Or was it further back than that?
Posted by: genixia

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 11:08

Speaking of British pennies, when did they stop being abbreviated as `d'? When you guys went from your old monetary system to the new decimal system (that was about 1965, right?)? Or was it further back than that?

IIRC, it was 1st Feb, 1971.
Posted by: Roger

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 11:18

Speaking of British pennies...

Yes, and it was 15th Feb 1971. See this and this.

Posted by: ashmoore

Re: Evolution of Technology based on Trivial Circu - 03/04/2002 12:24

Wow, you guys have all the answers
Yes I remember in school when it suddenly cost twice as much for my candy!