New York (the city at least) is quite well connected by rail.
And there go the mod points.
New York (the city at least) is quite well connected by rail.
And there go the mod points.
It matters a great deal, and making sure burst transfers are effective is not always possible.
I do high performance calculations for a living. Knowing in advance what you will need in the future is a somewhat hard problem (and the basis of most modern optimization.)
The difference between main memory and cache is vast, if you can predict what you need far enough in advance to load it into cache that helps quite a bit, but realize that normally at best you are loading 4x what you really will need (which is the nature of trying to predict it so far ahead of time you are not able to calculate what you will really need.)
If you want to contest that, how much memory do you have in cache compared to your data set of a few terabytes? Multiple cores are usually a loss in performance if you even try, most real world problem are not possible to run in parallel once you hit the easy optimizations (which mask latency for the most part at the expense of a large amount of cache memory.)
Most of the harder problems I have run into could scale across multiple cores (or CPUs) if it was designed that way, but the run time would always be worse than a solution which assumed that it will always run on one core (introducing synchronization points kills it.)
Latency is essentially everything in most applications which are optimized (most are not, it costs too much.) The recent trend of simply including more CPUs is essentially an acknowledgement that computers have almost hit their limit in terms of the number of sequential calculations they can run over time.
If you are assuming that your application will become faster as time goes on you already lost. In most cases this cannot happen unless the original implementation was highly suboptimal (such as... you used Java or C# instead of C, or your C code is terrible.)
Bring only basic items.
Clothing, toothbrush, toothpaste, and maybe a charger for the basic prepaid cellphone you picked up before you left.
Anything else is an invitation to theft, and you should consider it potentially lost before you leave. If you decide it is more important to bring your Ipad than leave it home so be it, but the potential cost to you is the cost of the device.
If your employer sends you, request a travel laptop. These are disposable, and it comes at no cost to you.
No technology will really prevent theft, especially since anything which will prevent access is also a potential threat to our friendly government, and can be impounded for a very long time.
So... travel light.
Get a full range of motion in your wrist as often as possible. About every 20 minutes I move my wrists to their full extent in all directions, move all finger joints to theirs (crack your knuckles both ways...) and touch each finger to each other one.
This only takes a few seconds to do with some practice.
Nearly zero problems after 20 years, it seems to work for everyone I have suggested it to.
I type very quickly, and both my leisure and day job require much typing. The pain goes away if you lubricate your joints and strengthen your muscles regularly.
It probably helps to be in good physical shape with adequate blood flow.
I bought a kindle for my girlfriend quite a while ago, and have used their store many times (one of the early models, and she is an avid reader.)
Your assertions are factually incorrect with regards to amazon (no idea about other vendors.) This is not a case of it changing over time either, the below has been true since the introduction of the kindle, and remains true to this day.
1) Not all e-books are DRM restricted.
Amazon offers many books which are out of copyright for free (which has probably led to a significant savings over time for me, as she likes to read the classics, and I would otherwise end up buying these in paper form.) Small publishers and self published works are also in many cases DRM free. We have purchased several of these from amazon as well, so they obviously exist.
2) Books from sources other than amazon can be loaded onto the kindle.
We have purchased several self published books directly from the author and loaded them onto the kindle, so these also obviously exist. I will also point out that various libraries lend current e-books which work on the kindle (including our local library.) It is free to borrow these, although it is time limited as with any other book checked out from a library.
The below includes some speculation, so it is not necessarily factual... but is most likely correct:
I seriously doubt the companies you listed conspired with publishers to "keep all the savings for themselves." The far more likely scenario is that these companies entered into an agreement with publishers who owned the sole publication rights to works they wished to carry in their store, so that they could... you know... carry it in their store. I am sure that amazon wants to make money on these as well, but I can hardly fault them for that (I also do not work unless I can make money from that work.)
One of the conditions was likely that they include DRM, and so they did. I am not obligated to purchase these if I do not wish to, and could in fact only purchase DRM free books for use with the kindle (from amazon or another store.) This would limit the selection of modern books, but it could be done (many could even be borrowed from the library... if we wanted to wait in line, as with any other popular physical book.)
There are some complaints to make here, but they are best leveled against the appropriate party. In this case publishers who are watching their industry collapse, and do not wish to embrace the changes our modern age brings. I do not believe amazon deserves this criticism however, and in fact think they deserve much credit for essentially creating the market.
I have no affiliation with amazon other than as a customer, and do not own their stock (I probably would, but their current valuation is hard to swallow.)
I imagine that by Barnes and Noble he means the physical store where you can buy a paper book, not the electronic reader.
Reading this article is kind of wild... I was approached to do a very similar project at around the time he would have written this software.
I refused it.
That decision cost me at the time. I nearly lost my job over it, annoyed everyone involved, and the company lost what had been a fairly profitable client (who referred it to us, and looked bad when I rejected it.)
He may not have known that he was likely to get into trouble over it, but that means he was not duly diligent. If I recall correctly the arguments against my stance that this was not legal were as follows:
1) Advertisements were running on TV for this type of gambling (I produced a letter the DOJ was circulating to advertisers at the time stating in no uncertain terms that they consider it illegal.)
2) It was not a US company, and it was ok to write it for them since they are not bound by US law (I argued that I am a US citizen, and am subject to US law regardless.)
3) The company would get into trouble, not me personally (I argued that this was possibly criminal, and they could pierce the veil over it.)
4) It was not my job to decide this, and I should basically just shut up and do it... or there would be consequences.
Everyone was very pushy about this. The direct payment would have been large, and it came with some ownership (likely a very substantial amount of money.) When I refused I got into a very serious argument with my boss.
This lasted about a week, and included having to join a couple of conference calls where I was yelled at for not being a team player, was told I was sabotaging the company, and that maybe I was not worth having around after all. I was also told that they would provide a poor reference if asked, and would make sure I lost the referring client (who I did lose over it.)
I still calmly refused, and eventually ended the conversations with "At the end of the day I either write this software or not. I will not, and you are now wasting your time in trying to change my mind."
I qualified my refusal with the conditions under which I would write it: which included either a license by a US based gaming commission which I believed covered what they wanted to do, or a letter of opinion from the DOJ that this did not violate the law. Neither of these applied, and so my refusal stood.
I am now very glad I decided not to do that project.
Currently I work as a CTO (obviously not at that company.) Product development is under my control, and a non-trivial part of the job is to consider the legal implications of what we do (legal usually reports to the CTO for a reason.)
Liability in software is the same as it is in any other industry, despite the fact that overhead is lower than most. If you produce a product you specifically know will be used for illegal purposes you can very much be held liable (in that case allowing US citizens to place bets on sporting events over the internet.)
If the primary use is legal and you make some effort to curtail illegal activity, it is generally not an issue. In this case he either knew or should have known that the primary use was not legal. His case is weak, and it likely would be better for him personally to take the plea bargain.
The solution to that problem is pretty easy.
If it becomes a problem, I imagine cars will begin to detect this and email a snapshot of the license plate plus evidence to local law enforcement. The end result would probably be much care in your actions around automated cars, as they will report your reckless driving.
If you had been reading financial news, you would already know that they are likely to go out of business soon.
This has been known for several months.
I am not addressing your arguments because I am not attempting to argue with you. While I could certainly allow this to become an argument over the results of applying relativity in the case you describe, I am not inclined to do that.
I am instead attempting to explain something to you, which is not the same thing. I do believe I know the source of your misunderstanding, which is what I am attempting to address.
The abstract concept of the infinite cannot be translated into the real world, you must be able to come up with a finite value for any practical application (or even an observation allowing one to test a theory.)
You can represent values on paper which do not exist in the real world. Ex: I can draw a unicorn, but trying to go find one would likely be a waste of time.
You are attempting to derive a physical result from something that is unphysical. This leads you to an interpretation of the world around us which is more restrictive than is implied by observation.
The note that you are a mathematician is amusing to me, my girlfriend asked me what I was doing the other day, and my reply was "trying to convey a point to someone... probably a math student."
If the student part is incorrect I apologize, but that comes from the constant arguments along the lines of "other guy is an idiot... who eats babies." This is not something you see often from those older than about 25, as it usually hurts your case more than helping it, and that is around the point by which most people will understand this.
It is unfortunately no longer a holiday, and my time is limited. You either get what I am saying or do not.
The mods liked that initial post because it clearly and concisely explained why your interpretation of reality is not necessarily the correct one.
I think you misunderstand your reference. The line "Assume tachyons exist and special relativity is correct" is a logical contradiction, and I will attempt to explain why.
The thought experiment you linked requires a logical violation which any person of reason knows to be impossible (specifically, greater than infinite energy.) It is not predicted by relativity, it is a discussion of what would happen if you tried to apply it in a situation to which you cannot apply it.
Einstein did a lot of this kind of thing (it was probably fun for him to discuss it.) It is not part of his theories on relativity, and you should probably look at it more as a discussion of the consequences of applying his theories in situations they are not meant to cover.
You are assuming greater than infinite energy AND time travel to even put it forward as an argument...
I see the greater than infinite energy requirement as a hard physical limit to the theory, and an implied limit for the equations involved. While this limit is not explicit in relativity, I think we can safely assume that Einstein did not intend for the theory to apply in a situation which requires greater than infinite energy.
As you approach the speed of light, energy input must approach infinity. To cross it requires a greater than infinite amount of energy.
This is impossible, both in theory and practice. This is not just a "we do not know how" situation, it is absolutely impossible within relativity.
If you do not understand why greater than infinite is absolutely impossible... I am not sure what else I can do to explain it.
He was aware that infinite + 1 does not really exist, you are apparently not. It is a "what if?" not a prediction.
Relativity is a physical theory, if you take it beyond this point you are talking about a purely mathematical construct. You cannot apply this to the physical world, as infinite + 1 does not exist here.
Relativity therefore prohibits producing a tachyon. It is impossible according to the theory due to the greater than infinite requirement, not the causality violation which this inappropriate input would produce.
Trying to do so anyway makes me think of the saying "garbage in, garbage out."
Everyone who initially discussed that was aware that it is an impossible scenario when they did so, which is why they assumed it for the purposes of that argument. They determined that the already impossible scenario would also produce causality violations, which means relativity breaks down here. This does not detract from the theory, as you cannot get this result with any valid input.
It is in fact theoretically impossible to produce a tachyon within relativity. Absolutely impossible.
If FTL communication is discovered at some point we are no longer living in a world ruled by relativity, and this must be accounted for. The theory prohibits this, and relativity has no appropriate application in an FTL scenario (this is WHY you get a causality violation.)
Causality is not relativity, it is merely that cause precedes effect. I am saying that while your observation of cause and effect may not be correct, it still does not allow you to change the past.
The cause comes before the effect, despite your observation of the order of events.
Let us construct a thought experiment of our own by taking a trip to sci-fi land:
Two advanced alien species are at war, and they have the capability to move objects from one point to another in the universe without crossing the space separating these two points (FTL.)
Side A fires an FTL missile which destroys a ship on side B.
The observation in half of the relativistic light cone will be that effect preceded cause (the missile destroys the ship before it is launched.)
So what happens?
1) Causality violation means that side B can fire their own FTL missile, destroy the ship on side A that launched the first one, and "undestroy" the one on side B by changing the past.
2) Causality remaining intact means that while side B can fire their own FTL missile and destroy the side A ship, the side B ship will remain destroyed, as this event has already happened.
I am stating that the observation of the order of events is inaccurate due to the introduction of FTL, and the second scenario is the correct one. Cause still comes before effect despite the fact that the order in which you observe events does not show this.
The information on the cause is relativistic, the information on the effect is not. You cannot use relativity to determine cause and effect here, but cause still came before effect.
He did, it is also known as an Einstein-Rosen bridge.
I do not believe that he made a statement one way or another as to if he thought it would actually allow causality violations though. In some cases it would be a definite no, but it may be possible in others.
As it is entirely theoretical at this point we obviously cannot determine that.
I am aware of this. Again, FTL communication is prohibited by relativity.
FTL communication would allow the imposition of a single frame of reference for all observers in the context of that communication, in order to allow communication it would be a requirement.
In this situation cause and effect must be viewed in that frame of reference. The timing of events may differ in your local frame of reference, but the order would be preserved in the frame of reference used by your communication.
To preserve causality all that would be required is that all observers use this frame of reference to determine cause and effect.
You would *not* be able to observe an object traveling faster than the speed of light without violating causality.
You seem to have entirely missed the point of most of that... but as I noted a lot of people have real trouble with it, and I have free time to explain it better as it is a holiday.
You cannot use relativity to predict what would happen in an FTL scenario, because it is not possible within relativity. Not possible as in there is no way to do it, it does not exist. You are making a conclusion based on a theory which absolutely prohibits the scenario you are describing.
You cannot get to the speed of light with a massive particle (never mind exceed it), and energy without mass cannot travel at any other speed (although you can affect the speed of light in a certain medium, so let me be clear that we mean "speed of light in a vacuum" as the limit.)
The prediction of relativity is that FTL does not happen, not that time travel exists when it does. To restate it again (man is this horse dead) relativity says that tachyons do not exist. They are not an aspect of relativity, they are prohibited by it. Any method of FTL communication is necessarily outside relativity.
Let us define some of this better, so that the argument may make some sense to you:
1) Improper time coordination:
One or both parties are willing to put their finger on the hour hand and move it to suit their needs. Their exchange does not violate causality because they bent the rules to make the scenario possible. This is not what you are talking about, but is a valid way the exchange you described can happen.
2) Assuming time travelling signals:
If you assume a signal can arrive before it is sent, you can obviously violate causality. This is exactly what you are talking about with that argument, but the outcome is taken as a given before the argument... It is however another valid way the exchange you described could happen.
3) A change in the maximum speed at which information can propagate:
Under relativity the maximum speed at which information can propagate is the speed of light. I am speaking of any method which allows you to send information such that it arrives at the destination before a light speed signal would (FTL.) This changes the maximum speed at which information can propagate.
How this occurs does not really matter in this context. It could be a completely unknown at this time fundamental force which does allow acceleration beyond this speed without greater than infinite energy, a way of sending something without it actually passing through the space separating the two points, whatever.
And now that definitions are out of the way...
The argument here is over what would happen in a situation in which there is a way to pass information such that it arrives before a photon could under relativity, more specifically if it must allow a causality violation.
You say it must necessarily allow effect to happen before cause, I say that is not assured.
The clock synchronization statement is to get rid of the first scenario I listed, as I mean to assume that both clocks are stating the same thing. If they are in motion relative to each other you must account for this (such as we do with GPS.)
It is easier to assume they are at rest with respect to one another (and does not detract from the argument to do so.) This lets us do away with relativity and use a Newtonian view of the universe with respect to the status of their clocks.
I suppose I can clarify this further by saying two points three light hours away from each other, but also with no relative motion with respect to one another (or anything else that would cause time dilation for either observer with respect to the other, such as gravitational forces.)
This leaves us with only the causality implications of the signal traveling faster than light (which is the discussion.)
This signal does not need to allow a causality violation, as no matter how "fast" it gets there the signal will never be received before it is sent (even if the time on both clocks does not change between when it is sent and when it is received.)
If a signal can transverse the three light hours in one second, you have FTL communication. You cannot however send the message, have the other party receive it, and send it back before it was sent.
Causality would be intact, but relativity would not.
The degree to which FTL communication would require changes to relativity depends upon how it is achieved, so that is difficult to speculate on. I will point out that while our world view changed when our understanding moved from Newtonian motion to relativistic motion, it does not mean that Newtonian motion is wildly inaccurate. What happened is that we understood more, and now have a theory which includes both what Newton described, and additional behavior which it did not. Relativistic effects are outside newtons theories of motion and cannot be described within it, much like FTL is outside relativity.
This may very well happen with relativity as well at some point in the future, as our understanding of the physical laws of the universe is most certainly not complete.
Your example says absolutely nothing about violation of causality due to a change in the maximum speed at which information can propagate. You are either describing a situation in which there is improper time coordination, or you are assuming time travelling signals to start with.
While there are no known methods by which information can propagate faster than light...
If something were to be discovered which could do this it would not necessarily violate causality, it would merely prove that relativity is either incorrect or incomplete (even if it were to allow instantaneous travel to any point in the universe, and the new maximum speed is therefore infinite.)
In order to violate causality you would need to be able to receive a message you sent before you sent it.
Instant propagation of information would likely allow a universal clock across all space, and you could coordinate time by that. You would need to adjust for the faster travel time if you are synchronizing your clock based on the speed of light, but it would be trivial to do that anyway.
Under relativity it is undefined what would happen if you could travel faster than light, as the theory does not allow this. It is basically not usable in this case, and trying to do so would be foolish (it simply does not cover what you want to do, and you obviously have information that Einstein did not when he came up with it if you are communicating FTL.)
If I could send this post beyond the edge of the known universe and back with zero travel time I still cannot read it before it is written, and causality remains very much intact.
The only thing that would change is that if you are three light hours away, I could get a message to you three hours before an electromagnetic signal would be capable of. We would be able to converse in real time instead of with the delay, nothing else.
If you could produce the post I just wrote before I wrote it, you would have a causality violation. No rate of travel allows this, no matter how large it is.
I am not sure why this is so hard for many people to understand.
A priest advised Voltaire on his death bed to renounce the devil. Replied Voltaire, "This is no time to make new enemies."