I'm just asking this because I read it downloads much faster on an SSD. Even much faster on a RAM disk. I have an older machine. I download the chain for 5 days. Does the downloading process or simply operating the client kill the hard drive?
No. Hard drives are designed to be used as hard drives, which is exactly what you are doing when using the computer with a hard drive. I hope this is clear enough. Could you explain why hard drives are different from GPUs or gasoline engines which have "health" decreased with excessive use? For example, assume you have two otherwise identical engines -- one has 10k miles on it, the other has 100k miles on it (or km). Why would the engine with less miles on it fetch a higher price, even if they were manufactured in the same year? Or for GPUs, a GPU used lightly should fetch a higher price than a GPU which mined for the past 3 years. They are otherwise identical, but one has more "wear." Why would a hard drive be any different? There is some normal wear of mechanical components with use, and this will eventually lead to failure. Before this point is reached, however, other causes may and do trigger failures: abuse, mechanical shocks, ESD, thermal stress cycles, dusty or smoky environment, etc. The probability of most of these does not increase with use. Failure due to thermal stress is in fact more likely in systems subject to on/off cycles (less use!) than those that are constantly turned on. Unlike GPUs or HDDs, internal combustion engines are mainly mechanical devices, with rather violent vibrations and stress in normal use, so wear and tear may in fact be a dominant mechanism of failure. Consumer hard drives are designed to be used as hard drives by consumers. Desktop computers, unlike servers, don't usually access the disks 24/7, so these drives are not designed to withstand such use (you have server-grade drives for that). It will create wear & tear which will shorten the expected component life. Whether this effect is significant with current usage pattern of bitcoin-qt is not something I can readily answer. It also depends greatly on the specific drive. Some drives park their heads when not actively seeking to spare the wear&tear of the heads hovering close to the platters. Constant usage can interfere with this endurance feature in various ways; it can prevent the heads from ever being parked, or worse, it can create repeated park/unpark operations, for which the drive is only rated for a certain number. With SSDs there is the well-known write endurance problem, and excessive random write operations can degrade the drive's write performance. |
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Update: The upcoming meetup on Jan 21 2013 has been moved to Google Tel Aviv new offices, Electra Tower, 98 Yigal Alon, Tel Aviv - floor 29.
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I think the three and four block sequence probabilities are negative binomial, and if so the median values will be ~ 25 minutes for 3 blocks and ~ 34 minutes for four blocks solved, which also look about right.
If we treat time as continuous it will be the continuous version of negative binomial, which is the Erlang distribution. |
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I misread the first post initially and did some incorrect math but still demonstrates this is a relatively likely event.
The probability of one block taking 127 minutes or more (simplified):
2^-12.7 = ~ 1/6654 = average one in 46 days worth of blocks
It's not 2^-12.7, it's e^-12.7 = 1 / 327748. This is an example for an event that will probably not happen in 4 years, but still has a reasonable chance. My result above is a binomial simplification of mining: The probability of a block being solved after 10 minutes: 50%, or 1/2 The probability of a block not being solved after 10 minutes: 50%, (1/2), or 2 ^ -1 The probability of a block not being solved after 20 minutes: 25%, (1/2)*(1/2) = 1/4, or 2 ^ -2 The probability of a block not being solved after 30 minutes: 12.5%, or 1/8, or 2 ^ -3 .... The probability of a block not being solved after 127 minutes: 2 ^ -12.7, or ~0.015% It's not a "simplification", it's just wrong. The probability of a block being solved within 10 minutes is not 50%, it's 63.21%. The probability that a block will take more than x*10 minutes to solve is exp(-x). 10 minutes is the mean, not the median. |
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I misread the first post initially and did some incorrect math but still demonstrates this is a relatively likely event. The probability of one block taking 127 minutes or more (simplified): 2^-12.7 = ~ 1/6654 = average one in 46 days worth of blocks Of course if you want to do real discrete statistics: At target 0000000000000529B10000000000000000000000000000000000000000000000 - difficulty = 3249549.5844872
- Probability per single hash = 0.000000000000000071649034700583570
- Expected number of hashes per 10 minutes = 13956922157834111
All calculations that have been shown expect the hashrate actually corresponds to difficulty, however there's enough of a pattern when summing many blocks-per-day-of-the-week intervals to know some people turn off mining on the weekends. It's not 2^-12.7, it's e^-12.7 = 1 / 327748. This is an example for an event that will probably not happen in 4 years, but still has a reasonable chance. |
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@organofcorti - I don't think "4 blocks in 127 minutes" is the correct way to look at the event, because what we can see here is actually an interval of (127 minutes - epsilon) with only 3 blocks. To simplify and clarify, let's look instead of the sequence of X1, X2, ... of time intervals between successive blocks. What we see here is a subsequence of intervals for which X1+X2+X3+X4 > 12.7 (I'm rescaling to have mean 1 for each interval). The probability for this with a specified subsequence is 0.13295%. Now we ask what is the chance of this happening in 4 years. It's easier and not much different to ask instead about the chance of this happening in a sequence of 210,000 intervals. If we denote Yi = X_{i}+X_{i+1}+X_{i+2}+X_{i+3} and u=12.7, the chance of this not happening is Prob [For all 0 <= i < 200996 Yi < u] = Product (i from 0 to 200996) of Prob [Yi < u | for all 0 <= j < i Yj < u] Y_k and Y_m are independent for |k-m|>3. Approximating the first few terms (not needed but slightly simpler) this is equal to Product (i from 0 to 200996) of Prob [Yi < u | Y_{i-1} < u, Y_{i-2} < u, Y_{i-3} < u] All multiplicands are equal, and their value is 1 + (u^2 (6 + 2 E^u (-3 + u) + u (4 + u)))/(6 (-2 - 2 E^(2 u) - u (4 + u) + E^u (4 + u (4 + (-1 + u) u)))) (Slightly higher than the unconditional probability) For u=12.7 this is 0.999202021115881015 So we're looking at 0.999202021115881015 ^ 200997 ~ 2 * 10^(-70) Probability of this not happening. The probability of happening is roughly 0.99999999999999999999999999999999999999999999999999999999999999999999979340994 89681. Edit: I'd be interested in hearing from anyone who can show me how to answer this question without having to assume the time is broken up into 16554 blocks of 127 minutes. I couldn't see how to do it.
I'm not sure I understand your question. The inter-event time for the Poisson process has http://en.wikipedia.org/wiki/Exponential_distribution . Are you talking about something else? Yes, he talked about the probability of an event like this ever happening in a 4-year span. |
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You should of course both save and spend. But make sure you consider the true valuation of your bitcoins including what it would take to obtain more. In some countries it's not that hard. Hoarding in an online wallet is the most hilariously stupid idea I have heard yet out of this community. And that's saying a lot.
What's the problem? As long as it's stored offline it should be pretty safe, or are you one of those crazies who think you should just spend everything you've carefully saved up and not think about the future at all? He was responding to this comment: ...I'm thinking of splitting my BTC in half within the next couple of days; half will go in an online wallet to hoard...
If by "online wallet" he meant a shared eWallet, then yeah, that's ill advised. |
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best way would be to relist the asset on some other exchange, pay the dividends that were not paid and then let it trade for a couple of months and buy back the bonds as per contract if you wish. You may also execute the buyback following the last trading data from GLBSE (should be found somewhere on these forums).
In all honesty re-listing sounds like a lot of work for miniscule return. For perspective; I own around half of the 800 bonds, the next largest holding is one quarter and the majority of the rest are single digit amounts (several, like my itchy trigger fingered friend strello, hold one (1) single bond). My feeling is that 1MH/s bonds are worth somewhere south of 0.05btc, based on the markets decline towards the end of GLBSE and diminishing returns from mining including the looming ASICpocalypse. Seeking opinions and evidence of similar bonds trading on the new platforms. Depends on how many bondholders you had. If you don't list somewhere, you have to process the last two months of dividends & buyback manually. Not a big deal if there aren't many, but can be a PITA if you have a lot. You don't need to do this manually for every bondholder. I have commented here with some notes about how to automate this. |
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Hello Meni, when you going to send rest of old dividends?
I thought I did, all coupons marked as "full" on http://bitcoinpuremining.com/ have been paid out to 15,566 bonds. Check the outgoing transactions from 1JPFCUtH2gcADar9xi3A9vStTr9Ba5XKvy. Edit: In your case, the original direct claim address you used was superseded by the official address from GLBSE, to which some of the payments were sent before you requested a change of address. |
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Are you Jewish/Israeli/know Hebrew ?
My last name not give it away?  I'm of Syrian Jewish decent. (My family lived in Spain until the inquisition in late 1400's) and I speak Hebrew and Arabic fluently (my arabic needs touching up, but I can read and write pretty well) - Charlie For all I know it's a nickname ... Cool. "Yankee" is a nickname. "Shrem" is his last name. I thought this was all common knowledge. Aw so my trip to Israel just barely missed this?! Too bad, would have loved to be at this upcoming meetup. Thanks so much for meeting up, Meni, it was a pleasure!
Sure, it's been great meeting you. You missed the boom but most of the buzz is online anyway, and the meetups are regular so you'll always be missing one. Guys, I can't help the feeling that Bitcoin is another Jewish scheme to take over the world... Is Satoshi Jewish?
The two smartest people in the world are Satoshi Nakamoto and Eliezer Yudkowsky, so it makes sense they are the same person. EY is Jewish so... |
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And just now Bitcoin was featured on "London and Kirshenbaum", also on channel 10. Their economic interpreter, Matan Hodorov, explained it reasonably. He has more to learn though, as he had to look at his notes to be able to tell the limit is 21M, and pronounced the creator "Satushi" (it's spelled the same in Hebrew).
Heh, I love that show. Link me to that episode? I think it's not up yet, will do when available. |
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And just now Bitcoin was featured on "London et Kirschenbaum", also on channel 10. Their economic interpreter, Matan Hodorov, explained it reasonably. He has more to learn though, as he had to look at his notes to be able to tell the limit is 21M, and pronounced the creator "Satushi" (it's spelled the same in Hebrew).
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It's not the first time Bitcoin was mentioned in newspapers and TV, and it's interesting Thursday's events had so much impact (Bitcoil: x10 the normal visits on Thursday, bitcoin.org.il: x100). I guess it's also a matter of timing and Bitcoin is now more ripe to be digested by the public. That guitar shop isn't even in Israel anymore. The owners (Josh and Zach Harvey) moved to New Hampshire and have various activities there (Zach recently gave a talk in the Philadelphia Bitcoin summit). Restaurants and cafes will come too, I know a few people but it takes time. Very encouraging, it's no surprise to hear that a small country with a fair concentration of science and technology industries (and hence alot of engineers and scientists) would build up a bit of popular interest.
It's been said that Israelis are also more distrustful and skeptical, so it's harder to get across revolutionary ideas. All in due time, though. |
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Just curious, about how many BTC were you thinking of selling it for?
Well, it would be tied to a USD amount. Probably somewhere around $60k. So about 4500 BTC at the current rate. If someone buys that, it'll make news everywhere.
From 5K BTC pizza to 5K BTC house. Nice. |
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I will not accept this. I've set my personal deadline in this case. After the deadline without significant and reliable progress in repayment, irreversible action will be taken without further announcement.
I'm trying to work towards people getting back as much of the debt as possible. Can you explain what your proposed course of action would accomplish? I appreciate your efforts. But I think they lack effectiveness. As my expectation of repayment of any significant proportion of the funds decreases, the importance of holding the fraudster liable increases regardless of a possible influence on the chances of repayment. Alberto can still stick to his words and implement a more reliable repayment schedule. But I certainly will not watch the current delaying game go on forever. There are some plans he told me about, I will bring your feedback to his attention and see if he has any ability to expedite the plans or to affirm his intention to go along with them. |
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Inetresting paper for the modelling part but rather weak in dealing with the economics of the double-spend.
I tend to agree, the economics part is not meant to be conclusive, rather act as a starting point for how an analysis could be done. For example
"An attacker with majority hashrate can not only double-spend any trans- action at no cost (above the cost of running the mining hardware normally)"
Wrong: the attacker can only double-spend his own coins, meaning he must earn or buy a stash of coins upfront. As a result of his attack, his cost includes the initial value of the coins (before the attack) minus whatever value is reached after the attack is stopped by counter-measures (like new check points in the blockchain or merchants temporarily holding deliveries on bitcoin payments).
This cost exists but as I explicitly stated, I don't think it's significant since other factors limit the possible scale of attack. More generally, you can include most "practical" costs as terms in the model. Future work will include formulating a model that can encompass most such things and be tractable to solve. Then it's just a matter of figuring out all the costs and plugging them in. The same flaw (silo thinking) was found in the microsoft paper that dealt with bitcoin endogenous inventives (algorithmic rewards) while ignoring completely exogenous incentives (contractual rewards).
There's something very basic about research papers that some people seem not to get. You can't give and solve a model that 100% accurately reflects reality. You need to make some simplifying assumptions and even if those assumptions aren't correct per se, they often have less effect on the final conclusions as it seems; even if the effect is significant, the more accurate model will rely on the intuitions of the simpler case. You don't formulate general relativity without first having a firm grasp of Newtonian mechanics. A big part of the trick is knowing when the assumptions are adequate, and how to refine them when they are not. |
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I dont want to check ~3500 posts, so could you just link some of your highest deals / PGP rating accs / ... so its easier to check? I know Meni a bit from the BDT drama so if your reported links aint too bad, i can provide $2000 @ 5% per 15 days. Right now i held $920 USD and €1000 EUR which can be exchanged.
Thanks, but I'm not interested in this offer. For reference, I've had several deals of >$10K which I've honored, but those were private so I won't disclose the details without the other parties' agreement. I appreciate looking at track record of actual deals made, but work towards the advancement of Bitcoin (and general RL reputation) are more important, and the reputation I've built is worth much more than $10K. I've summarized that in my vanity thread as linked in my signature and above by ripper234. PS I found some alternative means to the same end so while I may still be interested in the request in the thread, it's not as critical. |
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He negotiated debt relief (fixed USD/BTC exchange rate) based on empty promises. If he ever pays any significant amount it will be certainly only at a much higher USD/BTC exchange rate - allowing him to retain most of his fraudulently obtained BTC.
This argument makes no sense. The USD/BTC exchange rate can either go up or down. Fixing the debt at a given USD/BTC rate is the logical thing to do, not having done that sooner was a mistake. I will not accept this. I've set my personal deadline in this case. After the deadline without significant and reliable progress in repayment, irreversible action will be taken without further announcement.
I'm trying to work towards people getting back as much of the debt as possible. Can you explain what your proposed course of action would accomplish? |
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I'd imagine this should be moved to Meetups?
Wut? This is not just a meetup. This is probably the biggest in-person Bitcoin event of the year. I agree of course, but essentially it's a meetup so big people from all over the world are willing to travel to attend. So I think cross-posting on Meetups a link to here or the official thread (still waiting) is in order. |
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