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"You misunderstand. Our goal is to make computers easier to use, not to make
them more useful."
http://commandcenter.blogspot.com/2011/09/we-open-in-well-lit-corporate.html
--
Darren New, San Diego CA, USA (PST)
How come I never get only one kudo?
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On 27/09/2011 01:53 AM, Darren New wrote:
> "You misunderstand. Our goal is to make computers easier to use, not to
> make them more useful."
This would be quite amusing - if it wasn't actually /true/...
In seriousness, their goal is probably more like "to make products that
consumers will pay money for".
There's a whole bunch of things going on in this conversation -
management that don't know what they're trying to produce, engineers who
want to implement features just because it's possible to implement them,
and a man who's name is Dick...
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On 9/27/2011 4:12 AM, Invisible wrote:
> In seriousness, their goal is probably more like "to make products that
> consumers will pay money for".
^^ Truth.
--
~Mike
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Darren New <dne### [at] san rrcom> wrote:
> http://commandcenter.blogspot.com/2011/09/we-open-in-well-lit-corporate.html
"Books have never had search. If we add search, we'll just confuse the
user."
The correct answer should have been:
"Yes they have. Ever heard of indices? Also tables of content serve the
same role. That's how you know which page to jump to in order to find a
specific chapter. Indices can be used to search using a specific word. The
only difference is that in a physical book the amount of such words is
limited, which on a computer there's no limit."
--
- Warp
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On 27/09/2011 10:23 PM, Warp wrote:
> "Books have never had search. If we add search, we'll just confuse the
> user."
>
> The correct answer should have been:
>
> "Yes they have. Ever heard of indices?
Books had O(log N) lookup before computers were invented! :-D
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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On 28/09/2011 9:31 PM, Orchid XP v8 wrote:
> On 27/09/2011 10:23 PM, Warp wrote:
>
>> "Books have never had search. If we add search, we'll just confuse the
>> user."
>>
>> The correct answer should have been:
>>
>> "Yes they have. Ever heard of indices?
>
> Books had O(log N) lookup before computers were invented! :-D
>
Ever heard of catalogues or stacks?
--
Regards
Stephen
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>> Books had O(log N) lookup before computers were invented! :-D
>>
> Ever heard of catalogues or stacks?
Catalogues yes, stacks no.
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Orchid XP v8 <voi### [at] devnull> wrote:
> Books had O(log N) lookup before computers were invented! :-D
Computer algorithms are much older than computer themselves. Consider that
the first person who formalized the concept of "algorithm" as well as many
key concepts of computability was Alan Turing (yes, that Turing), who died
in 1954.
--
- Warp
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On 29/09/2011 11:33 AM, Warp wrote:
> Orchid XP v8<voi### [at] devnull> wrote:
>> Books had O(log N) lookup before computers were invented! :-D
>
> Computer algorithms are much older than computer themselves. Consider that
> the first person who formalized the concept of "algorithm" as well as many
> key concepts of computability was Alan Turing (yes, that Turing), who died
> in 1954.
The first "computer" was arguably the design by Babbage, and the first
"algorithm" was allegedly written by Ada Lovelace, who died almost
exactly 1 century before Turing.
Now if we could establish when the first book with an index was created...
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Le 2011-09-29 07:04, Invisible a écrit :
> On 29/09/2011 11:33 AM, Warp wrote:
>> Orchid XP v8<voi### [at] devnull> wrote:
>>> Books had O(log N) lookup before computers were invented! :-D
>>
>> Computer algorithms are much older than computer themselves. Consider
>> that
>> the first person who formalized the concept of "algorithm" as well as
>> many
>> key concepts of computability was Alan Turing (yes, that Turing), who
>> died
>> in 1954.
>
> The first "computer" was arguably the design by Babbage, and the first
> "algorithm" was allegedly written by Ada Lovelace, who died almost
> exactly 1 century before Turing.
>
> Now if we could establish when the first book with an index was created...
From www.merriam-webster.com:
Origin of INDEX
Latin indic-, index, from indicare to indicate
First Known Use: 1561
--
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/* flabreque */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/* @ */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/* gmail.com */}camera{orthographic location<6,1.25,-6>look_at a }
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Francois Labreque <fla### [at] videotronca> wrote:
> Origin of INDEX
> Latin indic-, index, from indicare to indicate
> First Known Use: 1561
The first known use of the word doesn't necessarily mean it's the first
known use of an index in a book.
--
- Warp
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On 29/09/2011 02:55 PM, Warp wrote:
> Francois Labreque<fla### [at] videotronca> wrote:
>> Origin of INDEX
>> Latin indic-, index, from indicare to indicate
>> First Known Use: 1561
>
> The first known use of the word doesn't necessarily mean it's the first
> known use of an index in a book.
True - but I think we can safely say that books had indicies /long/
before working computers even existed, which was my original assertion.
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On 29/09/2011 12:04 PM, Invisible wrote:
.
>
> The first "computer" was arguably the design by Babbage, and the first
> "algorithm" was allegedly written by Ada Lovelace, who died almost
> exactly 1 century before Turing.
>
I would argue that algorithms go further back than that. Consider
control mechanisms. If you want an engine to run at a constant speed
with a variable load. You would use an algorithm like this.
Test the speed of the motor.
If the speed is lower than the target speed then increase the power.
If the speed is greater than the target speed then decrease the power.
If the speed is within limits then neither increase nor decrease the power.
This was solved in 1788 with James Watt’s flyball governor. An analogue
solution to the algorithm. Roman engineers maintained water levels for
their aqueduct system by means of floating valves that opened and closed
at appropriate levels. Someone had to create an algorithm no matter how
simple.
> Now if we could establish when the first book with an index was created...
For library catalogues see
http://en.wikipedia.org/wiki/Library_catalog#History
Long, long ago.
--
Regards
Stephen
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Le 2011/09/29 09:55, Warp a écrit :
> Francois Labreque<fla### [at] videotronca> wrote:
>> Origin of INDEX
>> Latin indic-, index, from indicare to indicate
>> First Known Use: 1561
>
> The first known use of the word doesn't necessarily mean it's the first
> known use of an index in a book.
>
The first use of the word set a key date.
The first book with an index, even if named diferently, was made
strictly before that year.
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Le 2011-09-29 09:55, Warp a écrit :
> Francois Labreque<fla### [at] videotronca> wrote:
>> Origin of INDEX
>> Latin indic-, index, from indicare to indicate
>> First Known Use: 1561
>
> The first known use of the word doesn't necessarily mean it's the first
> known use of an index in a book.
>
Agreed.
but if the first documented use the word index to was in 1561, we can
safely assume that the first use of the index itself predates it. I was
only establishing the upper bound.
--
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/* flabreque */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/* @ */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/* gmail.com */}camera{orthographic location<6,1.25,-6>look_at a }
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On 9/29/2011 11:11 AM, Stephen wrote:
> This was solved in 1788 with James Watt’s flyball governor. An analogue
> solution to the algorithm. Roman engineers maintained water levels for
> their aqueduct system by means of floating valves that opened and closed
> at appropriate levels. Someone had to create an algorithm no matter how
> simple.
>
Depending on your definition of "computer", there is evidence of a one
of a kind "Roman" device that was capable of predicting eclipses, and
timing the correct date to start the Olympic games, among other
features. In other words, an electronic calender. But, at that time,
such things where nearly impossible to replicate, so when the ship it
was one sank... Arguably, its gearing system had to have some sort of
"algorithm".
https://secure.wikimedia.org/wikipedia/en/wiki/Antikythera_mechanism
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>> The first "computer" was arguably the design by Babbage, and the first
>> "algorithm" was allegedly written by Ada Lovelace, who died almost
>> exactly 1 century before Turing.
>
> I would argue that algorithms go further back than that.
At this point, it becomes necessary to define what you mean by "algorithm".
Is long division an "algorithm"? Because the ancient Babylonians
apparently had that waaay back in 3100 BC. That's some FIVE MILLENNIA ago.
What I actually /said/ was that computers (by which I mean fully
autonomous computational devices) had O(log N) lookup way later than
books (by which I mean large textual documents stored as visible marks
on some sort of medium) had it. Given how ancient writing is and how
comparatively new functioning computers are, I think that's a safe
assertion.
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On 30/09/2011 03:14 AM, Patrick Elliott wrote:
> Depending on your definition of "computer"
There is that too.
Turing-completeness is a reasonable definition, until you consider that
a sheet of paper and a pen is Turing-complete given a suitable human to
operate it. So perhaps the significant thing is the sophistication of
computations that the device can perform without human aid.
> there is evidence of a one
> of a kind "Roman" device that was capable of predicting eclipses, and
> timing the correct date to start the Olympic games, among other
> features.
Last I heard, nobody had decided exactly what that device was for. It
seems opinions have changed...
> In other words, an electronic calender.
I think you mean /automated/ calendar. It's only /electronic/ if it
operates by moving electrons around. :-P
> But, at that time,
> such things where nearly impossible to replicate, so when the ship it
> was one sank...
We're talking about something from a /long/ time ago. The fact that no
others have been found yet doesn't mean none existed.
> Arguably, its gearing system had to have some sort of "algorithm".
By that description, the way that trees use the laws of physics to move
exactly the right amount of water from their roots to their leaves could
be considered an "algorithm". Which would mean that algorithms predate
mankind by several billion years...
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On 30/09/2011 9:08 AM, Invisible wrote:
>>> The first "computer" was arguably the design by Babbage, and the first
>>> "algorithm" was allegedly written by Ada Lovelace, who died almost
>>> exactly 1 century before Turing.
>>
>> I would argue that algorithms go further back than that.
>
> At this point, it becomes necessary to define what you mean by "algorithm".
>
> Is long division an "algorithm"? Because the ancient Babylonians
> apparently had that waaay back in 3100 BC. That's some FIVE MILLENNIA ago.
>
I would define an algorithm the same way the Wiki does.
An algorithm is an effective method expressed as a finite list of
well-defined instructions for calculating a function.
So I would say that the steps for doing long division are an algorithm.
> What I actually /said/ was that computers (by which I mean fully
> autonomous computational devices)
What do you mean by "fully autonomous computational devices"?
had O(log N) lookup way later than
I am not familiar with the Big O notation so I misread your sentence. As
usual I tried to make some sort of sense out of what could have been
typos and or bad grammar and spelling.
So in English, if possible, what do you mean?
> books (by which I mean large textual documents stored as visible marks
> on some sort of medium) had it.
That is just juvenile and pompous. Only funny to a teenager.
> Given how ancient writing is and how
> comparatively new functioning computers are, I think that's a safe
> assertion.
Again it depends on your definition of computer and they don’t all work
using ones and zeros.
I have worked on computers that were solely pneumatic. They could add,
subtract multiply and divide. Standard components could extract square
roots integrate and average.
--
Regards
Stephen
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On 30/09/2011 9:18 AM, Invisible wrote:
> Which would mean that algorithms predate mankind by several billion
> years...
Let's not go down that road again :-P
--
Regards
Stephen
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>>> I would argue that algorithms go further back than that.
>>
>> At this point, it becomes necessary to define what you mean by
>> "algorithm".
>>
>> Is long division an "algorithm"? Because the ancient Babylonians
>> apparently had that waaay back in 3100 BC. That's some FIVE MILLENNIA
>> ago.
>
> I would define an algorithm the same way the Wiki does.
> An algorithm is an effective method expressed as a finite list of
> well-defined instructions for calculating a function.
> So I would say that the steps for doing long division are an algorithm.
And I would agree with you.
So, yes, algorithms go back way, waaaay further than Babbage and Lovelace.
>> What I actually /said/ was that computers (by which I mean fully
>> autonomous computational devices)
>
> What do you mean by "fully autonomous computational devices"?
Well, that's the killer, isn't it?
An abacus can add. But only if an intelligent human is operating it. All
the smarts are in the operator; the abacus is just a memory tool, really.
A pocket calculator can add. Even if it's operated by raindrops getting
the keys. The smarts are in the device.
Now, how the heck you formulate that into some kind of coherent
definition......
>> had O(log N) lookup way later than
>
> I am not familiar with the Big O notation so I misread your sentence. As
> usual I tried to make some sort of sense out of what could have been
> typos and or bad grammar and spelling.
> So in English, if possible, what do you mean?
The number of steps required to find what you want is proportional to
the logarithm of the size of the thing you're searching.
If you search for a definition by looking at every page in the book
until you find what you're after, the amount of work is obviously
directly proportional to the size of the book. On the other hand, if you
look it up in the index and then go straight to that page, the amount of
time is proportional to the logarithm of the number of pages.
In the former case, if you double the number of pages, you double the
time required to find anything. In the latter case, doubling the number
of pages has little effect on the lookup time. (Assuming the book was
already large to start with, of course.)
>> books (by which I mean large textual documents stored as visible marks
>> on some sort of medium) had it.
>
> That is just juvenile and pompous. Only funny to a teenager.
I wasn't trying to be funny. I was trying to phrase a definition which
would encompass things that don't look like modern hardback "books".
Things like rolls of parchment or stone tablets, etc.
>> Given how ancient writing is and how
>> comparatively new functioning computers are, I think that's a safe
>> assertion.
>
> Again it depends on your definition of computer and they don’t all work
> using ones and zeros.
> I have worked on computers that were solely pneumatic. They could add,
> subtract multiply and divide. Standard components could extract square
> roots integrate and average.
I'm well aware that there have been many computers that used decimal
instead of binary. (A few even used other number systems.) I'm aware
that people have made computers using a veritable zoo of mechanical,
hydrolic and other technologies.
Now, you need to be a little bit careful here: There is a distinction to
be made between devices that can "calculate" things, and devices which
are considered to be "computers". As far as I'm aware, none of the old
"analogue computers" were actually Turing-complete, and so strictly they
are /calculators/ rather than /computers/.
The history of /calculators/ obviously goes back far, far beyond the
history of /computers/. (Again, depending on how general your
definitions are.)
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On 30/09/2011 12:01 PM, Invisible wrote:
>
>>> What I actually /said/ was that computers (by which I mean fully
>>> autonomous computational devices)
>>
>> What do you mean by "fully autonomous computational devices"?
>
> Well, that's the killer, isn't it?
>
AI, I suppose.
> An abacus can add. But only if an intelligent human is operating it. All
> the smarts are in the operator; the abacus is just a memory tool, really.
>
> A pocket calculator can add. Even if it's operated by raindrops getting
> the keys. The smarts are in the device.
>
> Now, how the heck you formulate that into some kind of coherent
> definition......
>
When you do, submit it as a PHD thesis. ;-)
Actually I don't think that I agree with your comparison between the
abacus and pocket calculator. I think that the latter is just a better
type of the former.
>> I am not familiar with ...
>
> The number of steps required to find what you want is proportional to
> the logarithm of the size of the thing you're searching.
>
> If you search for a definition by looking at every page in the book
> until you find what you're after, the amount of work is obviously
> directly proportional to the size of the book. On the other hand, if you
> look it up in the index and then go straight to that page, the amount of
> time is proportional to the logarithm of the number of pages.
>
> In the former case, if you double the number of pages, you double the
> time required to find anything. In the latter case, doubling the number
> of pages has little effect on the lookup time. (Assuming the book was
> already large to start with, of course.)
Well put, that completely reverses what I thought you meant.
>
> I wasn't trying to be funny. I was trying to phrase a definition which
> would encompass things that don't look like modern hardback "books".
> Things like rolls of parchment or stone tablets, etc.
>
Fair point considering. :-)
>
> I'm well aware that there have been many computers that used decimal
> instead of binary. (A few even used other number systems.)
I've worked on at least one system that used BCD (Binary Coded Decimal)
>
> Now, you need to be a little bit careful here: There is a distinction to
> be made between devices that can "calculate" things, and devices which
> are considered to be "computers". As far as I'm aware, none of the old
> "analogue computers" were actually Turing-complete, and so strictly they
> are /calculators/ rather than /computers/.
>
Another problem of mine. I’ve never really managed to get my head round
“Turin Machine” or “Turin Completeness”. Does it mean a machine that can
alter its input or operating instructions or what?
Some of the analogue machines I’ve seen had to be manually reconfigured
for each problem they needed to solve. But it could be done.
> The history of /calculators/ obviously goes back far, far beyond the
> history of /computers/. (Again, depending on how general your
> definitions are.)
Indeed.
--
Regards
Stephen
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>> Now, how the heck you formulate that into some kind of coherent
>> definition......
>
> When you do, submit it as a PHD thesis. ;-)
Thanks. I'll pass.
> Actually I don't think that I agree with your comparison between the
> abacus and pocket calculator. I think that the latter is just a better
> type of the former.
In order to work an abacus, /you/ have to know that ten beans on one
line is worth one bean on the next line. With a pocket calculator, this
kind of thing is automatic. You don't have to understand it.
I will conceed that automation is a kind of "shades of grey" thing.
There are greater and lesser degrees of automation, rather than just
"manual" and "automatic".
>> I'm well aware that there have been many computers that used decimal
>> instead of binary. (A few even used other number systems.)
>
> I've worked on at least one system that used BCD (Binary Coded Decimal)
Yes, but generally you use BCD if you have a /binary/ system and you
specifically want to do exact /decimal/ arithmetic. (It's a well-known
fact that 1/10 is not representable as an exact binary fraction. In some
settings, that might be a problem.)
> Another problem of mine. I’ve never really managed to get my head round
> “Turin Machine” or “Turin Completeness”. Does it mean a machine that can
> alter its input or operating instructions or what?
> Some of the analogue machines I’ve seen had to be manually reconfigured
> for each problem they needed to solve. But it could be done.
The formal definition of Turing-completeness is abstract and technical.
Essentially Alan Turing proved two main things:
1. It is possible to build *one* machine that can perform *any* possible
calculation.
2. Some calculations are impossible.
[Simplifying wildly, of course.]
You would think that a more complex, more sophisticated machine would be
able to calculate more things than a simpler machine. In fact, it turns
out that if they are both Turing-complete, they can both calculate
exactly the same stuff. (The more sophisticated machine is probably much
/faster/, of course...)
Consider an analogue computer, for a moment. It might have circuits that
can add numbers together. But if I want to add up one million operands,
I need to wire together [at least] one million adder circuits.
Now consider a simple digital computer. It might have only one binary
adder circuit, and yet it can add up an unlimited number of operands,
with unlimited precision.
Analogue computer: More steps = more hardware.
Digital computer: More steps = more time.
That's a fundamental difference. If I have an analogue computer with ten
adder circuits, I cannot add up eleven numbers. But if I have a
Turing-complete machine, I can add up an /unlimited/ number of operands.
You never need more hardware. It just takes more time.
This difference comes about mainly because a digital computer has a
/memory/. It can /store/ operands and feed them through its arithmetic
circuits one at a time. An analogue computer can't do that, so it has to
have one dedicated circuit for each step of the process. A digital
computer can /reuse/ the same circuits again and again for different
steps, because the steps won't happen all at once.
Also, you can often "program" an analogue computer. But you basically do
that by rewiring it. The machine can't rewire itself. But a
Turing-complete machine can have self-modifying code.
Actually /proving/ that something is Turing-complete is usually not
simple at all. But probing that something /isn't/ Turing-complete just
requires you to find one thing that it can't do [and a Turing-complete
machine can].
You could say it's a calculator if it only calculates one thing (e.g., a
mechanical tide predictor), it's a calculator construction kit if it can
calculate many things (e.g., a typical "programmable" analogue
"computer"), and it's a computer if it's Turing-complete (i.e., it has a
stored program, decision-making capabilities, etc.)
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On 30/09/2011 2:25 PM, Invisible wrote:
>>> Now, how the heck you formulate that into some kind of coherent
>>> definition......
>>
>> When you do, submit it as a PHD thesis. ;-)
>
> Thanks. I'll pass.
>
LOL
>> Another problem of mine. I’ve never really managed to get my head round
>> “Turin Machine” or “Turin Completeness”. Does it mean a machine that can
>> alter its input or operating instructions or what?
>> Some of the analogue machines I’ve seen had to be manually reconfigured
>> for each problem they needed to solve. But it could be done.
>
> The formal definition of Turing-completeness is abstract and technical.
> Essentially Alan Turing proved two main things:
>
> 1. It is possible to build *one* machine that can perform *any* possible
> calculation.
>
> 2. Some calculations are impossible.
>
> [Simplifying wildly, of course.]
>
> You would think that a more complex, more sophisticated machine would be
> able to calculate more things than a simpler machine. In fact, it turns
> out that if they are both Turing-complete, they can both calculate
> exactly the same stuff. (The more sophisticated machine is probably much
> /faster/, of course...)
>
Thanks
> Consider an analogue computer, for a moment. It might have circuits that
> can add numbers together. But if I want to add up one million operands,
> I need to wire together [at least] one million adder circuits.
>
> Now consider a simple digital computer. It might have only one binary
> adder circuit, and yet it can add up an unlimited number of operands,
> with unlimited precision.
>
> Analogue computer: More steps = more hardware.
> Digital computer: More steps = more time.
>
> That's a fundamental difference. If I have an analogue computer with ten
> adder circuits, I cannot add up eleven numbers. But if I have a
> Turing-complete machine, I can add up an /unlimited/ number of operands.
> You never need more hardware. It just takes more time.
>
> This difference comes about mainly because a digital computer has a
> /memory/. It can /store/ operands and feed them through its arithmetic
> circuits one at a time. An analogue computer can't do that, so it has to
> have one dedicated circuit for each step of the process. A digital
> computer can /reuse/ the same circuits again and again for different
> steps, because the steps won't happen all at once.
>
Not so, an analogue machine can have memory. A capacitor will store a
voltage until another arithmetic step is added to it. So that argument
does not hold water.
> Also, you can often "program" an analogue computer. But you basically do
> that by rewiring it. The machine can't rewire itself. But a
> Turing-complete machine can have self-modifying code.
>
That makes more sense to me.
> Actually /proving/ that something is Turing-complete is usually not
> simple at all. But probing that something /isn't/ Turing-complete just
> requires you to find one thing that it can't do [and a Turing-complete
> machine can].
>
> You could say it's a calculator if it only calculates one thing (e.g., a
> mechanical tide predictor), it's a calculator construction kit if it can
> calculate many things (e.g., a typical "programmable" analogue
> "computer"), and it's a computer if it's Turing-complete (i.e., it has a
> stored program, decision-making capabilities, etc.)
>
Hmm! I don't know. You can do some very intricate and complicated things
with analogue electronics. Consider the brain. O_o
--
Regards
Stephen
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>> The formal definition of Turing-completeness is abstract and technical.
>> Essentially Alan Turing proved two main things:
>>
>> 1. It is possible to build *one* machine that can perform *any* possible
>> calculation.
>>
>> 2. Some calculations are impossible.
>>
>> [Simplifying wildly, of course.]
>>
>> You would think that a more complex, more sophisticated machine would be
>> able to calculate more things than a simpler machine. In fact, it turns
>> out that if they are both Turing-complete, they can both calculate
>> exactly the same stuff. (The more sophisticated machine is probably much
>> /faster/, of course...)
>>
>
> Thanks
>
>> Consider an analogue computer, for a moment. It might have circuits that
>> can add numbers together. But if I want to add up one million operands,
>> I need to wire together [at least] one million adder circuits.
>>
>> Now consider a simple digital computer. It might have only one binary
>> adder circuit, and yet it can add up an unlimited number of operands,
>> with unlimited precision.
>>
>> Analogue computer: More steps = more hardware.
>> Digital computer: More steps = more time.
>>
>> That's a fundamental difference. If I have an analogue computer with ten
>> adder circuits, I cannot add up eleven numbers. But if I have a
>> Turing-complete machine, I can add up an /unlimited/ number of operands.
>> You never need more hardware. It just takes more time.
>>
>> This difference comes about mainly because a digital computer has a
>> /memory/. It can /store/ operands and feed them through its arithmetic
>> circuits one at a time. An analogue computer can't do that, so it has to
>> have one dedicated circuit for each step of the process. A digital
>> computer can /reuse/ the same circuits again and again for different
>> steps, because the steps won't happen all at once.
>>
>
> Not so, an analogue machine can have memory. A capacitor will store a
> voltage until another arithmetic step is added to it. So that argument
> does not hold water.
I was under the impression that a capacitor only holds its charge for a
very short period of time.
Regardless, have you ever actually seen an analogue computer with
independently addressable memory cells? I haven't heard of such a thing.
>> Also, you can often "program" an analogue computer. But you basically do
>> that by rewiring it. The machine can't rewire itself. But a
>> Turing-complete machine can have self-modifying code.
>
> That makes more sense to me.
On the other hand, if the connections were controlled by an array of
relays or something, and the computer could control the relays... then
you would be progressing towards a more truly programmable system.
> Hmm! I don't know. You can do some very intricate and complicated things
> with analogue electronics. Consider the brain. O_o
Well, strictly speaking, every digital computer is also an analogue
computer. They're just designed and used differently.
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On 30/09/2011 3:11 PM, Invisible wrote:
> I was under the impression that a capacitor only holds its charge for a
> very short period of time.
>
Depends what you mean by very short period of time. Most circuits that
use large capacitors will have a discharge resistor in parallel to stop
the capacitor holding the charge when the power is off. In domestic
appliances such as radios and TVs, it was recommended that you wait 20
minutes after switching off before working on them.
Also see:
http://en.wikipedia.org/wiki/Regenerative_capacitor_memory
> Regardless, have you ever actually seen an analogue computer with
> independently addressable memory cells? I haven't heard of such a thing.
>
What to answer first? I don't know, the only actual working valve
computer I've ever been in the presence of was at Glasgow University,
over 40 years ago. I've never had hands on experience working with them.
But you would not use addressable memory as you would in digital
computers. Remember that we are talking about voltage levels
representing numbers. Also back in the day, what was being asked of then
was much simpler and less complex so a lot of memory would not have been
required.
>> Hmm! I don't know. You can do some very intricate and complicated things
>> with analogue electronics. Consider the brain. O_o
>
> Well, strictly speaking, every digital computer is also an analogue
> computer. They're just designed and used differently.
And use different principles.
http://en.wikipedia.org/wiki/Analog_computer#Electronic_analog_computers
or
http://www.bookrags.com/research/analog-vs-digital-computing-wcs/
--
Regards
Stephen
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On 9/30/2011 2:48, Stephen wrote:
> An algorithm is an effective method expressed as a finite list of
> well-defined instructions for calculating a function.
So, a cake recipe isn't an algorithm? I'll have to disagree.
> So in English, if possible, what do you mean?
O(lg N) approximately means the number of steps it takes to do something is
roughly proportional to the number of digits in the input. So looking up a
word in the index of a book, then turning to the page number, is
approximately difficult based on the number of letters in the longest word
of the index, the number of digits in the page numbers the index covers, and
the number of digits in the pages of the book.
--
Darren New, San Diego CA, USA (PST)
How come I never get only one kudo?
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On 9/30/2011 6:25, Invisible wrote:
> Now consider a simple digital computer. It might have only one binary adder
> circuit, and yet it can add up an unlimited number of operands, with
> unlimited precision.
Except that a Turing machine has an unbounded amount of memory, so you're
not really comparing apples to oranges here.
> Analogue computer: More steps = more hardware.
> Digital computer: More steps = more time.
The digital computer requires more hardware too, in terms of "tape". All
those numbers you're adding have to be in the input somewhere.
> That's a fundamental difference. If I have an analogue computer with ten
> adder circuits, I cannot add up eleven numbers. But if I have a
> Turing-complete machine, I can add up an /unlimited/ number of operands. You
> never need more hardware. It just takes more time.
You never need more hardware because, by definition, Turing machines have
unbounded amounts of hardware attached. If you had an unlimited number of
analog ALUs, you'd be golden with an analog computer.
> Also, you can often "program" an analogue computer. But you basically do
> that by rewiring it. The machine can't rewire itself. But a Turing-complete
> machine can have self-modifying code.
You do it by rewiring a Turing machine, also. It just so happens that
because you have an unlimited amount of memory, you can wire up one computer
that will simulate whatever other computer you put in the memory units
(i.e., the "tape"). You could do the same with an analog computer as well.
> Actually /proving/ that something is Turing-complete is usually not simple
It's usually not too hard. You just write a turing-machine simulator in
whatever system you're trying to prove is turing complete. If you can
simulate a turing machine with an analog computer, then that analog computer
is turing complete.
--
Darren New, San Diego CA, USA (PST)
How come I never get only one kudo?
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On 30/09/2011 05:53 PM, Darren New wrote:
> On 9/30/2011 6:25, Invisible wrote:
>> Now consider a simple digital computer. It might have only one binary
>> adder
>> circuit, and yet it can add up an unlimited number of operands, with
>> unlimited precision.
>
> Except that a Turing machine has an unbounded amount of memory, so
> you're not really comparing apples to oranges here.
Yeah, one of the details I glossed over.
If I have a normal desktop PC then /in principle/ I can insert an
endless number of disks into it. Obviously, a Turing machine is a
mathematical abstraction. No physical machine can have infinite
anything, because the universe is finite.
> You never need more hardware because, by definition, Turing machines
> have unbounded amounts of hardware attached. If you had an unlimited
> number of analog ALUs, you'd be golden with an analog computer.
Small difference: ALUs require energy. A storage medium typically doesn't.
>> Also, you can often "program" an analogue computer. But you basically do
>> that by rewiring it. The machine can't rewire itself. But a
>> Turing-complete
>> machine can have self-modifying code.
>
> You do it by rewiring a Turing machine, also. It just so happens that
> because you have an unlimited amount of memory, you can wire up one
> computer that will simulate whatever other computer you put in the
> memory units (i.e., the "tape"). You could do the same with an analog
> computer as well.
If you're saying "you could make an analogue computer that was
Turing-complete" then, yes, of course you could. If you're saying "the
analogue computers what people actually built were Turing-complete"
then, no, not really...
>> Actually /proving/ that something is Turing-complete is usually not
>> simple
>
> It's usually not too hard. You just write a turing-machine simulator in
> whatever system you're trying to prove is turing complete.
Exhibit A: Totallistic cellular automaton number #110.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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On 30/09/2011 5:44 PM, Darren New wrote:
> On 9/30/2011 2:48, Stephen wrote:
>> An algorithm is an effective method expressed as a finite list of
>> well-defined instructions for calculating a function.
>
> So, a cake recipe isn't an algorithm? I'll have to disagree.
Be my guest.
See if I care :-P
--
Regards
Stephen
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On 9/30/2011 10:04, Orchid XP v8 wrote:
> Small difference: ALUs require energy. A storage medium typically doesn't.
ALUs don't require much energy. Look up "reversible computing" some time.
That's what it's all about. And yes, people have actually built computers
that take no energy to run, using quantum effects.
> If you're saying "you could make an analogue computer that was
> Turing-complete" then, yes, of course you could. If you're saying "the
> analogue computers what people actually built were Turing-complete" then,
> no, not really...
Well, sure, and neither are the real digital ones. That's kind of my point.
> Exhibit A: Totallistic cellular automaton number #110.
Exactly.
--
Darren New, San Diego CA, USA (PST)
How come I never get only one kudo?
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On 9/30/2011 1:18 AM, Invisible wrote:
> On 30/09/2011 03:14 AM, Patrick Elliott wrote:
>
>> Depending on your definition of "computer"
>
> There is that too.
>
> Turing-completeness is a reasonable definition, until you consider that
> a sheet of paper and a pen is Turing-complete given a suitable human to
> operate it. So perhaps the significant thing is the sophistication of
> computations that the device can perform without human aid.
>
>> there is evidence of a one
>> of a kind "Roman" device that was capable of predicting eclipses, and
>> timing the correct date to start the Olympic games, among other
>> features.
>
> Last I heard, nobody had decided exactly what that device was for. It
> seems opinions have changed...
>
>> In other words, an electronic calender.
>
> I think you mean /automated/ calendar. It's only /electronic/ if it
> operates by moving electrons around. :-P
>
Uh, yeah.. lol
>> But, at that time,
>> such things where nearly impossible to replicate, so when the ship it
>> was one sank...
>
> We're talking about something from a /long/ time ago. The fact that no
> others have been found yet doesn't mean none existed.
>
This is true, but from a purely practical standpoint, the expense,
precision, and engineering needed to get just "one" to work, using
basically copper and bronze gears, and little if any fast and replicable
casting methods (where talking hand making each gear here), the odds of
an exact copy is pretty much nil. The odds of something similar, still
close to zero. Something much simpler.. possibly, but its basically a
clock, more or less, and I am pretty sure that water clocks where just
about as close as they ever got, based on everything known/found/written
about, other than this thing, to that level of precision. Even some
mechanisms they used in temples, to open and close doors, where "one
off" designs, which where never exactly replicated, and are only half
known, half speculated, at this point (given the missing bits, and
descriptions we have to go off of).
If you wanted something that could use water to time things to the hour,
or measure an exact amount of "holy water" to do something with in a
temple, you where in good shape, since the mechanisms didn't need to be
*that* precise. Something like a mechanical calender... Hope you own
stock in the Colosseum. lol
>> Arguably, its gearing system had to have some sort of "algorithm".
>
> By that description, the way that trees use the laws of physics to move
> exactly the right amount of water from their roots to their leaves could
> be considered an "algorithm". Which would mean that algorithms predate
> mankind by several billion years...
Umm, well.. I would argue that what makes it an algorithm is the
"intentional" development of the steps and process needed to form a
predictable result. Gearing matches this definition. Stuff that just
kind of does that already, naturally... is a bit iffier. But, that isn't
to say that, say genetics, couldn't contain something that could be
"interpreted", if you had the right JIT compiler, so could be, to an
extent, algorithmic. Water happening to get from roots to leaves.. not
so much.
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On 9/30/2011 8:47 AM, Stephen wrote:
>> Regardless, have you ever actually seen an analogue computer with
>> independently addressable memory cells? I haven't heard of such a thing.
>>
> What to answer first? I don't know, the only actual working valve
> computer I've ever been in the presence of was at Glasgow University,
> over 40 years ago. I've never had hands on experience working with them.
> But you would not use addressable memory as you would in digital
> computers. Remember that we are talking about voltage levels
> representing numbers. Also back in the day, what was being asked of then
> was much simpler and less complex so a lot of memory would not have been
> required.
>
Just use a large, covered, lake as the "storage". You get a certain
level of error, and possible leaks, but you could compute a number as
large as... what ever the lake could contain in what ever unit of water
your system dealt with. lol Seriously though, I would say that the
distinction between digital and analog in this sense is a) how long you
can hold the value, and that assumption that the value you can hold has
a set number of limits, in DNA, assuming you where using it to encode
numbers, that is like what 4 values (ATGC), in some indefinite set of
combinations, 3 states, for like the "quantum" systems they are trying
to develop, or 2, on/off, for current systems. In all of these cases,
the "values" are discrete, hence digital. You can't, in the case of
something like DNA "get" any other values (unless you just completely
change the proteins involved), I am not sure what you get with quantum
effects, but generally they seem to be discrete states, but with binary
we *intentionally* ignore any difference of state, other than below X
level, or above it. So, if your "analog" circuit had these values 0.1,
0.3, 0.6, 0.12, and 0.7, "binary" simply enforces the rule that this is
actually 00101.
In principle, your "analog" computer just throws out that assumption.
The result is less reliable, which is the main reason we stopped trying
to use it. But, in theory, if someone had wanted to, they maybe could
have made a base 10 computer, by treating each "range", 0-0.1, 0.11-0.2,
etc. as a different "state". It probably wouldn't have been at all
feasible, in that the fail rate on circuits that didn't produce the
correct result, or match specifications, would have been much, much,
larger. Like, if now we threw out one in every 1,000 processors, you
might see a fail rate of like 1:50 for such a base 10 system, or worse.
Because, of you are dealing with on and off, 0.6-1.0 is "acceptable" for
the "on" state, and 0-0.4 might be for the "off", with only the absolute
middle range of values being too ambiguous.
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Le 2011/09/30 22:17, Patrick Elliott a écrit :
> On 9/30/2011 8:47 AM, Stephen wrote:
>>> Regardless, have you ever actually seen an analogue computer with
>>> independently addressable memory cells? I haven't heard of such a thing.
>>>
>> What to answer first? I don't know, the only actual working valve
>> computer I've ever been in the presence of was at Glasgow University,
>> over 40 years ago. I've never had hands on experience working with them.
>> But you would not use addressable memory as you would in digital
>> computers. Remember that we are talking about voltage levels
>> representing numbers. Also back in the day, what was being asked of then
>> was much simpler and less complex so a lot of memory would not have been
>> required.
>>
> Just use a large, covered, lake as the "storage". You get a certain
> level of error, and possible leaks, but you could compute a number as
> large as... what ever the lake could contain in what ever unit of water
> your system dealt with. lol Seriously though, I would say that the
> distinction between digital and analog in this sense is a) how long you
> can hold the value, and that assumption that the value you can hold has
> a set number of limits, in DNA, assuming you where using it to encode
> numbers, that is like what 4 values (ATGC), in some indefinite set of
> combinations, 3 states, for like the "quantum" systems they are trying
> to develop, or 2, on/off, for current systems. In all of these cases,
> the "values" are discrete, hence digital. You can't, in the case of
> something like DNA "get" any other values (unless you just completely
> change the proteins involved), I am not sure what you get with quantum
> effects, but generally they seem to be discrete states, but with binary
> we *intentionally* ignore any difference of state, other than below X
> level, or above it. So, if your "analog" circuit had these values 0.1,
> 0.3, 0.6, 0.12, and 0.7, "binary" simply enforces the rule that this is
> actually 00101.
>
> In principle, your "analog" computer just throws out that assumption.
> The result is less reliable, which is the main reason we stopped trying
> to use it. But, in theory, if someone had wanted to, they maybe could
> have made a base 10 computer, by treating each "range", 0-0.1, 0.11-0.2,
> etc. as a different "state". It probably wouldn't have been at all
> feasible, in that the fail rate on circuits that didn't produce the
> correct result, or match specifications, would have been much, much,
> larger. Like, if now we threw out one in every 1,000 processors, you
> might see a fail rate of like 1:50 for such a base 10 system, or worse.
> Because, of you are dealing with on and off, 0.6-1.0 is "acceptable" for
> the "on" state, and 0-0.4 might be for the "off", with only the absolute
> middle range of values being too ambiguous.
>
There is another consideration: Power consumption and heat dicipation.
With a binary gate, you consume almost no power on a zero or a one. You
do consume a lot more when you switch value and are at an intermediate
state.
With a decimal processor using 10 ranges, 8 times out of 10, you are at
a steady intermediate state that forces you to dicipate much more heat.
Things get even worst if you want to create an analog logic switch.
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>>> But, at that time,
>>> such things where nearly impossible to replicate, so when the ship it
>>> was one sank...
>>
>> We're talking about something from a /long/ time ago. The fact that no
>> others have been found yet doesn't mean none existed.
>>
> This is true, but from a purely practical standpoint, the expense,
> precision, and engineering needed to get just "one" to work, using
> basically copper and bronze gears, and little if any fast and replicable
> casting methods (where talking hand making each gear here), the odds of
> an exact copy is pretty much nil. The odds of something similar, still
> close to zero. Something much simpler.. possibly, but its basically a
> clock, more or less, and I am pretty sure that water clocks where just
> about as close as they ever got, based on everything known/found/written
> about, other than this thing, to that level of precision.
That's interesting, because Wikipedia claims there's a long documented
history of ideas similar to this one, starting with Archimedes...
>>> Arguably, its gearing system had to have some sort of "algorithm".
>>
>> By that description, the way that trees use the laws of physics to move
>> exactly the right amount of water from their roots to their leaves could
>> be considered an "algorithm". Which would mean that algorithms predate
>> mankind by several billion years...
> Umm, well.. I would argue that what makes it an algorithm is the
> "intentional" development of the steps and process needed to form a
> predictable result.
Indeed.
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On 30/09/2011 07:32 PM, Darren New wrote:
> On 9/30/2011 10:04, Orchid XP v8 wrote:
>> Small difference: ALUs require energy. A storage medium typically
>> doesn't.
>
> ALUs don't require much energy. Look up "reversible computing" some
> time. That's what it's all about. And yes, people have actually built
> computers that take no energy to run, using quantum effects.
I thought the problem with reversible computing is that it's just as
likely to run backwards (which is no use at all) as to run forwards?
>> If you're saying "you could make an analogue computer that was
>> Turing-complete" then, yes, of course you could. If you're saying "the
>> analogue computers what people actually built were Turing-complete" then,
>> no, not really...
>
> Well, sure, and neither are the real digital ones. That's kind of my point.
By that definition, nothing that can exist in the physical universe will
ever by Turing-complete. That's not a useful definition.
>> Exhibit A: Totallistic cellular automaton number #110.
>
> Exactly.
You said "it's always absurdly easy to prove that something is
Turing-complete". I hold up an example of something that took ages to
prove, and even now some people argue the proof isn't very sound.
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On 10/3/2011 1:03, Invisible wrote:
> I thought the problem with reversible computing is that it's just as likely
> to run backwards (which is no use at all) as to run forwards?
Yes. Basically, it takes as much energy as you need to keep it moving
forward. The less energy you give it, the slower it goes. If you give it no
energy, it stops (on average) making forward progress.
OK, it doesn't take *no* energy. It takes arbitrarily little energy.
> By that definition, nothing that can exist in the physical universe will
> ever by Turing-complete. That's not a useful definition.
Yes it is, if what you're talking about is what's possible to even
theoretically calculate.
> You said "it's always absurdly easy to prove that something is
> Turing-complete".
No I didn't. I said it's "usually not too hard."
> I hold up an example of something that took ages to prove,
> and even now some people argue the proof isn't very sound.
Sure. But that's because he's pushing the boundary. He's not interested in
whether a CA can be Turing complete. He's interested in the absolute
simplest CA that can be proven to be Turing complete. I'd argue that that's
intentionally on the very boundary of what's most difficult to prove, rather
than the "usually" case.
--
Darren New, San Diego CA, USA (PST)
How come I never get only one kudo?
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On 10/3/2011 1:01 AM, Invisible wrote:
>>>> But, at that time,
>>>> such things where nearly impossible to replicate, so when the ship it
>>>> was one sank...
>>>
>>> We're talking about something from a /long/ time ago. The fact that no
>>> others have been found yet doesn't mean none existed.
>>>
>> This is true, but from a purely practical standpoint, the expense,
>> precision, and engineering needed to get just "one" to work, using
>> basically copper and bronze gears, and little if any fast and replicable
>> casting methods (where talking hand making each gear here), the odds of
>> an exact copy is pretty much nil. The odds of something similar, still
>> close to zero. Something much simpler.. possibly, but its basically a
>> clock, more or less, and I am pretty sure that water clocks where just
>> about as close as they ever got, based on everything known/found/written
>> about, other than this thing, to that level of precision.
>
> That's interesting, because Wikipedia claims there's a long documented
> history of ideas similar to this one, starting with Archimedes...
>
Not always evidence they where actually built though. And, again, its a
matter of "size" and "complexity". Heck, even Babbage ran into the issue
of, "I think this will work, but there is no way in hell I could ever
build this thing."
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>> That's interesting, because Wikipedia claims there's a long documented
>> history of ideas similar to this one, starting with Archimedes...
>>
> Not always evidence they where actually built though.
There seems to be plenty of documentation of people who claim to have
seen these devices in operation.
> And, again, its a
> matter of "size" and "complexity". Heck, even Babbage ran into the issue
> of, "I think this will work, but there is no way in hell I could ever
> build this thing."
No, that wasn't the problem. Babbage's problem was that he kept
tinkering with the design. Always thinking up new ways to improve it.
Eventually the workmen got hacked off with trying to build a design that
changes every five minutes. Plus, I gather Babbage was not a patient
man, and rather awkward to work with.
In a way, he seems to have been like me: Full of good ideas, but an
incurable tinkerer, and never actually finished anything...
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On 10/4/2011 1:08 AM, Invisible wrote:
>> And, again, its a
>> matter of "size" and "complexity". Heck, even Babbage ran into the issue
>> of, "I think this will work, but there is no way in hell I could ever
>> build this thing."
>
> No, that wasn't the problem. Babbage's problem was that he kept
> tinkering with the design. Always thinking up new ways to improve it.
> Eventually the workmen got hacked off with trying to build a design that
> changes every five minutes. Plus, I gather Babbage was not a patient
> man, and rather awkward to work with.
>
> In a way, he seems to have been like me: Full of good ideas, but an
> incurable tinkerer, and never actually finished anything...
Sounds like the guy that worked for Twain, when he was trying to help
fund a printing press. The "simpler" model won out, despite the fact
that the one they where funding could do vastly more. The guy making it
kept taking it apart, to "improve" the thing, instead of ending up with
a fully working model.
Still, its been argued that it would have been problematic mass
producing the thing, at the time, too. Or, at least I read that some place.
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>> In a way, he seems to have been like me: Full of good ideas, but an
>> incurable tinkerer, and never actually finished anything...
> Sounds like the guy that worked for Twain, when he was trying to help
> fund a printing press. The "simpler" model won out, despite the fact
> that the one they where funding could do vastly more. The guy making it
> kept taking it apart, to "improve" the thing, instead of ending up with
> a fully working model.
Why Projects Are Delivered Late And Over Budget. Robertson et al.
...or not. ;-)
> Still, its been argued that it would have been problematic mass
> producing the thing, at the time, too. Or, at least I read that some place.
Depending which "thing" you refer to...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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