Saw it for the first time today and it is now my standard first reference to the question "but what exactly is Bitcoin?". Sure it glosses over the details of some concepts but for the target audience it is well designed without descending into techno babble. http://www.youtube.com/watch?v=QyVeHC4X2eA |
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I remember at one time someone had created a photo/background which had bitcoin logo and behind it there was a "sea" of stylized dots representing nodes and the connections between them. I have later seen it used in articles and blog posts but I can't seem to find it now.
Anyone know what I am talking about or do I just sound like a crazy person.
Mods if this should be moved go ahead, I wasn't really sure where "I lost an image someone else made related to Bitcoin" goes.
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How many times have you heard that (never backed up claim)? Infographic in MIT technology review.  |
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Early statements seemed to suggest that this issue was limited only to custom implementations and services relying on the unconfirmed transaction id as proof of payment. That normal users running standard clients were fine. This however isn't exactly the case anymore with one or more unknown third parties spamming modified versions of any transactions they receive into the network. First let me say, none of this should be considered giving MtGox a pass. Their issues go beyond just transaction mutability and the way they handled the issue was just awful however we can't pretend this isn't an issue for average users. I am running the stock reference client (Bitcoin QT or bitcoind) and don't externally use tx ids for any backend processing. Am I stick affected?Yes although the level this affects you may vary depending on your usage. The Bitcoin reference client as currently implemented (i.e. QT client & bitcoind) does rely on transaction ids which can produce some unexpected behavior for end users. Other major clients are likely affected to some degree you should contact the developers of those clients for more information. To provide some reassurance these issues do not result in a risk of losing funds, but they can lead to scenarios which are confusing and complicated to resolved. The long term goal should be immutable transaction ids (hashes) but a short term patch is also needed to make the behavior of the client predictable and intuitive. The two major areas that a "normal user" will encounter unexpected client behavior relating to mutable transactions are duplicate transactions being reported & unconfirmed change output breaking subsequent transactions. What is the problem with duplicate transactions being reported?The first issue is that the QT client is blissfully unaware of the fact that a transaction is a duplicate (same inputs, outputs, and fee) of another transaction, so it reports both txs to the user as if they are unique transactions. This can be confusing to the user. It may appear they received two payments, or that they accidentally spent coins twice. Not only is the transaction reported twice, the duplicate(s) are included in the balance reported to the user which further reinforces the perception that the duplicates are an additional unique transaction. This also appear to affect the balances in the "accounts" system of the reference client. How can Transaction Mutability break break transactions which use unconfirmed change outputs?All transactions use as their inputs (money going in) the outputs of a prior transactions. The reference client as well as other major clients does not allow users to spend the output of unconfirmed transactions. This is done for obvious reasons, the incoming transaction may never be confirmed and that would prevent any subsequent transactions from confirming as well. If the clients allowed it this could be chained to involve many people. Bob sends a coin to John who uses it unconfirmed to send a coin to Sarah who uses it unconfirmed to send a coin to Bill. If Bob's tx doesn't confirm (say Bob double spent John, or the tx was spammy with no fee) then all the other tx break. Most clients however make an exception for unconfirmed change (i.e. output from a transaction back to the same wallet). In the absence of a third party intentionally mutating transaction hashes this presents no issue as the wallet can be confident the transaction will eventually be confirmed. The active efforts of malicious third parties, to mutate transactions however makes that assumption flawed and it should be changed. Side note on inputs & outputs If you understand how Bitcoin "really works" you can skip down to the example and conclusion. For those who are operating under an abstracted understanding of Bitcoin using "address balances" belief that Bitcoin works on "address balances" the rest won't make much sense without a little background on how Bitcoin "really works". This is a very high level explanation and a lot has been left out or abstracted away but it isn't important to the discussion of the issue. Forget about address or wallet balances. Bitcoin works on the concept of inputs and outputs. The input of every transaction is the output of some previous transaction. When a user "sends coins" to you, in that tx he is creating an new output which until spent can be used in as the input of a new tx. The output is "locked" to your corresponding private key so it can only be spent by you. When you "spend" those "coins" you are creating a new transaction which uses up that output by putting it in the input of this new transaction and in the process create one or more new outputs. Those outputs can be used in subsequent transactions by the holder of the corresponding private key. The process of creating a transaction "spends" previous unspent output which is referenced in the input side of the transaction making it spent. There is no such thing as a half spent output. All outputs are either unspent (never included as an input in another transaction) or spent (included as an input in a transaction). Since an output can't be "half spent" when the value one is attempting to transfer is less than the value of the output(s) being spent then the client will add a new output equal to the difference which goes back to the users wallet. This is commonly called "change" or a "change output". If you had a 1 BTC unspent output and wanted to spend 0.6 BTC your client would create a new transaction which includes a single input that references the 1 BTC unspent output and two outputs, one would have a value of 0.6 BTC to the recipient and the second would have a value of 0.4 BTC back to your wallet. So 1 BTC in and 1 BTC out. Prior to the transaction you had an unspent output with a value of 1 BTC. After the transaction that output would be considered spent by the network. Instead you would have a new unspent output with a value of 0.4 BTC. The receiver would also have an unspent output with a value of 0.6 BTC.
The key point to take away is you don't transfer balances. A transaction "spends" one or more specific, unique unspent outputs by referencing them in the input side of the transaction and the creates one or more new specific, unique outputs by stating the value and conditions for use in the output side of the transaction. All outputs in the bitcoin network are unique and are explicitly referenced in the transaction by their unique tx id and index. The input portion of a transaction identifies the specific, unique output(s) being "spent" in the transaction by their unique combination of transaction id and index.. The input of a transaction doesn't reference a generic value (i.e. "spend one of my BTCs at this address") it references a specific output of a specific transaction (i.e. "spend output #0 of tx id 0e11592f65c349e44363362fe78791ccf3777da31b6bb0217422140212884356). If the transaction id of the output being spent changes (and is included in a block) after the new transaction is created then it is referencing a transaction id which while valid can never be confirmed (because only one of the transactions in a pair of duplicates can be included in a block and the "other one" already is). At a protocol level the potential for an issue applies to any unconfirmed unspent output being spent in a new transactions. The protocol makes no distinction between "normal" and "change" outputs. Everything is an output. However all "stock" clients prevent the user from spending unconfirmed outputs received from outside the wallet so unless you are running a modified or custom client the issue practically is limited to change outputs. The reference client (and AFAIK many others) exempt "change" outputs from the requirement of being confirmed before being spent. The tx id is being relied upon by the client while it is still mutable. The tx id of the change output being spent may be modified, and the chance of that happening is now greatly increased due to ongoing malicious modification of transactions by one or more unknown third parties. An example might help. Lets image a hypothetical user which has a single unspent output worth 1 BTC and the user spends 0.6 BTC. A very simplified view of the tx would look something like this (non relevant portions removed) Tx Id: "A"
-------
Inputs
[0]: <prior tx hash> <prior tx index> Value: 1.0 BTC
Outputs
[0]: <PubKey Of Receiver> Value: 0.6 BTC <- Payment
[1]: <PubKey Of Change Address> Value: 0.4 BTC <- Change
Now this transaction is signed and hashed. The transaction id is the computed hash, which in this example is "A". The problem occurs if the user makes another spend before tx A is confirmed in a block. There is no method for a user to restrict the client to only use confirmed change outputs in a new transaction. So lets see what happens if the user creates a new tx and spends 0.3 BTC more. Tx Id: "B"
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Inputs
[0]: Tx_Id: A Tx_Index: 1 Value: 0.4 BTC <- Note the reference to "A".
Outputs
[0]: <PubKey Of Second Receiver> Value: 0.3 BTC
[1]: <PubKey Of Second Change Address> Value: 0.1 BTC
Now this transaction is signed and hashed. The hash is "B". Contrary to popular understanding of "spending coins", the user isn't spending some generic 0.4 BTC "balance" he is spending a specific unique output (id: "A", index: 1). If a third party mutates tx "A" so this it now has a tx id of "Z", and "Z" not "A" ends up in a block first, then transaction "B" will never confirm. It output it references (id: "A", index: 1) in the input side of the transaction can never be included in a block because "Z" already is. Potential short term fixes:The first issue is really just a reporting issue. The client is reporting data to the user which is confusing or inconsistent. Clients should still record duplicate transactions but they should one a single tx in a duplicate pair should be shown to the user. When the client computes the balance of the wallet, duplicates (both received and sent) should be excluded from the total. Ultimately It doesn't matter which one of the duplicates is hidden as long as only one is shown. The client will need to handle a situation where if flags and hides one transaction in a pair of duplicates and that ends up being the one which gets included in a block. For consistency the confirmed transaction should always be shown to the user and the unconfirmed one hidden. When this happens the user would see no change other than the tx id would change when the duplicate is included in a block. The second issue can't be fixed other than by preventing the use of unconfirmed change. The client could either by default or by user set option block all unconfirmed outputs from being spent. The capability to do this already exists in clients as they already block the spending of "non-change" unconfirmed outputs. Change would be treated the same as any other output. Just 1 confirm is sufficient to ensure the tx id won't change in most cases. In some situations this may result in the user not being able to make a second transactions until the change from the first one is confirmed. Wallets can preemptively seek to reduce this scenario by monitoring the number of available outputs. When the number of outputs is low, the client could use more than one change output in the next outbound transaction. This requires no protocol changes because the protocol has no concept of "change" and already supports having more than two outputs. A client could even prompt a user to authorize (will require wallet to be unlocked) the creation of a "splitting" transaction if the number of outputs is very low and the value is very high. A wallet with a three outputs with a value of one BTC each is more flexible than a wallet with only one output with a value of three BTC so the wallet could recommend the user split the output. While these changes wouldn't make transactions immutable they would make the behavior of clients more consistent with the expectations of users and avoid confusing situations that can arise from transactions being mutated. On edit: Changed title and introduction to reflect recent updates. On edit2: Yes mutability is a word. OO languages have a concept of mutable (changeable) vs immutable (unchangeable) objects. You can stop PM me that the "correct" word is malleable. They are synonyms and developers programmers working in high level OO languages are more likely to use the word mutable over malleable. http://en.wikipedia.org/wiki/Immutable_object |
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On The Morning Edition, CBC Kitchener-Waterloo was able to successfully transmit Bitcoin over radio waves.
This makes what is believed to be the first known transmission of the digital currency by a public radio station.
A series of beeps were played over the air, and listeners were asked to use an app known as chirp.io to decipher a code produced by the sound.
Chris Skory of Rockland County, New York was the winning recipient, and unlocked 0.05 Bitcoin worth about $40. The Bitcoin was donated by Waterloo start-up Tinkercoin and a local Bitcoin enthusiast.
"I did not think that I was going to get it at all," said Skory. "I figured there was going to be some pretty stiff competition out there." http://www.cbc.ca/news/canada/kitchener-waterloo/cbc-kw-sends-bitcoin-over-the-airwaves-1.2503580 |
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Are there any press release distribution companies which accept Bitcoins?
I always like to spend real money when I can. I doubt it but I thought I would ask before using a company which only accepts dead presidents.
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When asked “have you ever heard of Bitcoin before today,” 48% of Indonesian respondents said yes, followed by 45% in Vietnam, and 34% in the Philippines — all Asian countries. South Africa and Mexico had the lowest response rates of 13% and 16% respectively.
58% of all respondents said they would “feel comfortable” investing in virtual currency. This number was highest in Kenya (74%), which could be due to the popularity of its mobile money service M-Pesa, which means people are already comfortable with digital money. Brazil and Mexico were the only countries where less than 50% of respondents would feel comfortable investing money in virtual currency. http://venturebeat.com/2013/12/19/this-is-what-people-in-9-emerging-markets-think-about-bitcoin-survey/ |
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Note: This is a beta test of service provider we are considering when we resume operations. Invoices will be created manually, there may be issues, the cashier may be confused, and it may be a waste of your time. Please don't offer unless you are willing to participate in a beta test. If testing is positive this will be rolled out in new sales portal launching in December so if you don't like rough edges but want to pay cash for bitcoins just say tuned.
This is a limited offer for 6-8 individuals today to test a payment providers. We will probably conduct another test run after the Thanksgiving break and are looking for soft launch of sales portal under the brand name BitSimple in early December.
Terms:
* One sale (max of $500) per person only.
* Each transaction is for $100 to $500. There is a fee if $3.99 added to the sale amount.
* You will pay cash at any 7-11 store in the United States and receive your coins today (likely within minutes).
* The exchange rate will be MtGox last at the time of your payment.
* Available in USD only, must be located in the US and have a 7-11 location nearby (should be 99% of the US).
If interested send me a PM with the following:
* First & last name.
* Bitcoin address to receive the coins.
* Either an email address (will need printer) and/or mobile phone number (will need a smartphone with internet access).
* Amount of purchase ($100 to $500).
I will manually generate an invoice for you. The invoice can either be sent by txt message (contains a link) and displayed on a smart phone or sent by email and printed. If you want I can send it both methods. You will need to bring the invoice (or your phone with invoice webpage) and cash to any 7-11 store in the United States to make a payment. Once payment is confirmed (real time) coins will be sent to the address you provided. Remember at this time it is a manual process but verification and delivery of coins should be fairly quick. Once again understand this is just a beta test, I am interested in feedback before we launch a sales portal.
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Why does bitaddress.org use uncompressed pubkeys for paper wallets? Is there a reason or is it just an oversight? At this point all services should be encouraging the use of compressed pubkeys and support for uncompressed pubkeys should just be for backwards compatibility. Can anyone think of a reason other than just it being an oversight for generating new paper wallets with uncompressed pubkeys? As an example, Bitaddress > PaperWallet > Generate Private Key:
5JgfcLRNEASqdrLKktL8Ygcftj9S7DTvSFYnMUtdd5Bmn8G9oYz
Address:
1Lux7wJ4cyoVqG3N3oWuitYmGpxZaK8nM3
Using the private key 5jgf... produces the following PubKeys (compressed & Uncompressed): 0x02 4649935EA7EB7A0B39021F07B41F20E12324CF2329569117157536C2A416FDA70x04 4649935EA7EB7A0B39021F07B41F20E12324CF2329569117157536C2A416FDA7971262798AFAB30BC060C03540E5E7451170256C4DC77C4C0CF7F3A1FAD75FF6 Addresses: 1F2NCcW4LCe7FebbqL89NpZKZ6gPNEDWzT (from the compressed PubKey) 1Lux7wJ4cyoVqG3N3oWuitYmGpxZaK8nM3 (from the uncompressed PubKey) Note that the bitaddress paper wallet option outputs the 1Lux address. Why waste blockchain space? |
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Selfie – "a photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website" – has been named word of the year by Oxford Dictionaries editors, after the frequency of its usage increased by 17,000% over the past 12 months.
....
OED's Word of the Year shortlist
bitcoin, noun:
a digital currency in which transactions can be performed without the need for a central bank. Also, a unit of bitcoin. [ORIGIN early 21st century: from BIT, in the computing sense of "a unit of information" and COIN.]
The term first appeared in late 2008 in a research paper, and the first bitcoins were created in 2009. By 2012, the virtual currency was attracting wider attention and we began to see its steadily increasing use. A spike in usage was apparent in March–May 2013, which may be due in part to the market crash around that time.
http://www.theguardian.com/books/2013/nov/19/selfie-word-of-the-year-oed-olinguito-twerkWell at least Bitcoin made it to the short list. The pick of "selfie" seems downright stupid to me. Even if Bitcoin hadn't "won" there are far better choices with staying power. I will punch myself in the face and take a self portrait if people are still using "selfie" in ten years. |
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That is the 12 millionth bitcoin mined.
The coin supply will reach 12,000,000 BTC (~$2.4 billion at current exchange rate) on block 270,000 or about 3,200 blocks from now.
When will it happen?
At 10 minute per block interval (no hashrate growth) it will be ~ 21 days.
At current average block interval (~7 min per block) it will be ~14 days.
Interesting factoid, at 12M BTC in circulation it will only require an exchange rate of ~$217 to make an all time high in the value of the money supply (incorrectly called "market cap"): $2.61B
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I figured I would start this thread as a place to collaborate on immersion cooling. The type of immersion cooling I am interested in is two phase passive semi-open bath. Wow that is a mouthful. So lets start with the basics. What is immersion cooling?Immersion cooling is a method of heat transfer where the device to be cooled (namely SHA-256 processor) is immersed in a heat transfer fluid (also called working fluid). It is helpful to remember that "fluid" doesn't necessarily mean liquid, "Freon" is a form of working fluid although most people think of it as a gas. Technically even air is a working fluid. Heat sinks transfer heat to passing air and fans are pumps designed to move low density gas instead of higher density liquids. Most people don't refer to air cooling as immersion cooling but it may help to understand some of the concepts if you think of Freon, water, and air as working fluids in heat transfer. Is immersion cooling the same thing as "water cooling"? With immersion cooling the heat is transferred directly from the heat source to the working fluid. In "watercooling" the working fluid is potentially harmful to electronics and thus flows through a sealed loop isolated from the heat source. A watertight waterblock is used to indirectly transfer the heat from the heat source to the working fluid. With immersion cooling the working fluid must be non-conductive and that generally limits us to three families of fluids: deionized water, mineral oil, and fluorocarbon-based fluids (namely Fluorinert made by 3M). Immersion cooling systems have higher fluid cost than watercooling but this is partially offset by the elimination of individual waterblocks. What is Two Phase Cooling?Well lets start with what is one phase cooling. In a mineral oil or deionized water system the working fluid never boil or freezes and always remains in a single liquid phase. Cool fluid is pumped past the heat source, where thermal energy is transfered to the fluid by conduction which raises the temperature of the fluid. The heated fluid is then pumped to a heat exchanger where it is cooled and pumped back to the heat source. The heat transfer is known as "sensible heat", and the more heat (thermal energy) transferred into the working fluid the more its temperature rises. The rise in temperature can be controlled by the fluid flow rate. The faster the fluid flow rate the less energy will be transferred into each unit of fluid and the lower the temperature rise will be. In two phase cooling the working fluid boils and thus exists in both a liquid and gas phase. The system takes advantage of a concept known as "latent heat" which is the heat (thermal energy) required to change the phase of a fluid. The working fluid is only cooled by boiling and thus remains at the boiling point ("saturation temperature"). Energy is transferred from the heat source into the working fluid will cause a portion of it to boil off into a gas. The gas rises above the fluid pool where it contacts a condenser which is cooler than the saturation temperature. This causes the fluid to condense back into a liquid and fall (rain) back into the pool. What is "open bath" or "semi open bath" means?Open Bath (sometimes more correctly called semi open bath) means the tank containing the heat source, working fluid and condenser is not a pressure vessel. The pressure inside the tank/container will be roughly the same pressure as the outside air (<1 PSI difference). This makes the tank easier and cheaper to construct and the system is never pressurized at dangerous pressures. In a open bath system equilibrium is achieved by having a condenser capable of sufficient heat transfer to condense the vapor at the same rate it is being produced by boiling. The volume of vapor remains relatively constant and prevents a rise in pressure. If the fluid boils at a faster rate than the condenser can condense it back into a liquid then the pressure in the tank will rise and vapor will be lost. This can be prevented by a safety pressure switch. Why not used deionized water (DI)?DI is electrically non conductive but it isn't inert. It will rapidly pull ions from the surrounding material until it reaches a point where it becomes conductive and damages the cooled components. Proper immersion cooling with DI requires expensive ion exchange systems and replacement ion exchange resin to continually remove build up of ions in the water. This process needs to operate continually which increases the cost and the system is never stable. Without maintenance and continual inspection the system can allow a build up of ions that eventually destroys the equipment being cooled. While immersion cooling with DI is a viable method it is ill-suited for unmonitored environments. Why not use mineral oil?Mineral oil is a single phase cooling system and for any significant heat load will require actively circulating the oil across the processors. Mineral oil also has a high viscosity and will need powerful pumps capable of handling the higher pressure. The system needs to be carefully designed to ensure each processor receives sufficient flow. Mineral oil has a relatively low heat capacity and thermal conductivity which increases the required flowrates and necessitates the use of larger heat exchangers. What types of power densities are possible?3M has conducted experiments cooling 4KW heat loads using 1L of working fluid so in theory heat densities approaching 4,000 W/L are possible. The constraint on commercialization is that existing servers have relatively low energy densities (well low relative to the limits of immersion cooling). Even a high end 3U server (4 CPU, multiple GPUs, 4+ 1200W PSU) may only have an energy density of 100W per Liter. However SHA-256 ASICs have very high energy densities although current systems have server like energy densities due to the limits of air or water cooling. Take a look inside the case of any 2nd gen ASIC design what takes up the most space? Air. The actual ASIC boards are very energy dense however there are surrounded by a significant amount of empty space. Remember these are using boards designed for air/water cooling. It may be possible to improve energy density by making custom compact boards. As an example of what is possible KNCs ASIC boards are 225 cm2 of surface area and use ~120W. If boards were stacked 1cm apart that would be an energy density of >500 W/L. Hashfast pcb design (subject to change) is even more energy dense, 280W of power in 240 cm2. In spaced in a cooling pool 1cm apart that would be an energy density of ~1,200 W/L*. Another way to look at it is hashing density. At 1cm spacing KNC would be a hashing density of >500 GH/L and Hashfast would be > 1500 GH/L. * There is limited information available on height clearance of HF boards. If the large FET heatsinks are not removable it may limit the spacing of boards in a cooling pool.How is the condenser cooled?The condenser could be cooled using refrigerant directly but a water loop (glycol/water mix) may be a more flexible and economical solution. The water loop can either be cooled using a commercial water chiller or using a dry tower in ambient air (heat exchanger and fans outside). The cooling loop will need to be sized large enough to transfer the full heat load out of the water loop. The advantage of FC-72 over other two-phase working fluids is it has a 56C boiling point which allows reasonable efficiency when cooling using outside air even during summer temps for most parts of the country. The larger difference between the input air (ambient outside air temp) and the input water temp (~50C to 56C) means more efficient heat transfer is (smaller fans, smaller heat exchanger). What working fluids are available?3M makes a large number of synthetic working fluids however for two phase cooling we are interested in fluids which boil below the temperature limits of ASICs. Remember in two phase cooling the fluid will remain at saturation temp (boiling point) excess thermal energy is removed from boiling however the temperature of the fluid will remain in equilibrium at saturation temp. It is not possible with two phase cooling to have temperatures less than the boiling point of the working fluid. 3M datasheet on all heat transfer fluids: http://multimedia.3m.com/mws/mediawebserver?mwsId=tttttviZIdW5_y7VPZA_qZ0t2XV62EW9iXut2Xut2tttttt--&fn=bro_heattrans.pdfFor this reason the following fluids are most applicable: Novec 7000 - Boiling Point 34C FC-3284 - Boiling Point 50C FC-72 - Boiling Point 56C Novec 7100 - Boiling Point 61C FC-770 - Boiling Point 95C (likely too high outside of custom design) The cost depends on supplier and volume being purchased but generally runs $80 to $100 per Liter. Fluorinert is often priced by the kilogram and has a high density (1.6 kg per Liter) so take that into consideration if you think you found a "deal". |
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Need a new PSU for your ASIC mining rig(s). All prices in BTC only at Bitstamp last price at the time of payment. Available: 4x COOLER MASTER Silent Pro Gold 1200W - $150 ea plus actual USPS shipping 3x SeaSonic X-1250 1250W - $200 ea plus actual USPS shipping COOLER MASTER Silent Pro Gold Series 1200W (RSC00-80GAD3-US) http://www.newegg.com/Product/Product.aspx?Item=N82E16817151109http://www.coolermaster-usa.com/product.php?product_id=2999&product_name=Silent%20Pro%20Gold%201200WSeaSonic X-1250 1250W http://www.newegg.com/Product/Product.aspx?Item=N82E16817151109http://www.seasonicusa.com/NEW_X-series_1050-1250.htmThey units were used for about 15 months as part of a watercooled GPU farm. I was saving them for potentially powering future ASIC rigs but I have found a larger alternate power source. I recently tested units under load with ATX power supply tester and they are all within voltage spec. Both brands are solid performers, even under high load. 80-Plus Gold means it is 89%+ efficiency (92%+ on 240V) even at 100% load. They both have 8 PCIe connectors and massive 12V single rail designs so they can pump out a huge amount of current for even the hungriest ASIC rigs. IMHO build quality on the Cooler Master units is decent but the SeaSonics are second to none which is why I discounted the CM more. I have all the original modular cables and cable bags. Do not have original boxes or manuals if that matters. It will be most economical to ship INSIDE USA because power supplies are heavy an bulky but they fit in a USPS larger (possibly medium need to test) box which is cheap. Will take some actual photos of the units tomorrow including hooked to voltage tester. |
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 Always wondered. Looking at the photo it appears the caps are for the 12V distribution and the ATX PSU provide very good regulation why does the PDU need caps? |
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Moderated version. The original thread (now locked) is useful to see how the numbers evolved. The ideaThe purpose is to try to guesstimate (and yes that means error) the amount of hashpower in "the pipeline". If there were no pre-orders, difficulty would rise based on sales and that makes future sales less attractive (lower ROI%) which reduces the amount of future sales. This economic feedback model constrains hashing power based on efficiency, electrical cost, capital cost, exchange rate, the risk premium miners are willing to accept and the time value of money. GPU didn't continue to grow to petahash scale because as new hardware was deployed it lowered the reward and increased the risk on future hardware and this slowed the growth until a rising exchange rate improved the reward. Preorders break this feedback cycle as difficulty doesn't rise until delivery. This can result in sold (but undelivered) capacity growing faster and larger than would happen if it was constrained by immediate feedback. This is a great scenario for hardware vendors; they can sell more hardware, earlier and at higher prices. On the other hand it means miners may face an avalanche of hardware purchased by their peers who don't quite understand how high difficulty can go. Accurately projecting growth for any period of time longer than a month is probably an exercise in futility. We can however look at it from a different direction; if we can guesstimate the amount of preorders and can also estimate delivery timeframe then we can use that for the basis of a curve. So throw me your cites, guesstimates, and official numbers to try an pin down how much capacity has already been purchased. The rules1) To keep this thread from derailing please leave the "xyz is a scam" or "abc sucks because ..." posts for another topic.
2 ) No idea/number is bad. Please be respectful. Honestly nobody knows for sure, except the chip makers and they aren't talking.3 ) To stay on topic I will erase anything even remotely in violation of rule #1 and #2 4 ) A good starting point is the total amount preordered. It may not be realistic but it provides a starting point. 5 ) Right now we aren't so much worried how likely a plan is just that there is a plan. We can discount the hashpower by probability later (on edit: starting separating unfunded plans from presales and investor funded operations) 6 ) If you have a reference or cite (even unofficial) to back up a guestimate please link to it. 7 ) If there is no reference a reasonable explanation is more useful then just posting a number. "Show your work". 8 ) We can safely assume that all non-ASIC hashrate will go to zero so no need to break it out between delivered and ordered. Eventually hashrate ~= total pre-orders. 9 ) Mining companies buying retail product won't be listed seperately as they should already be included in the chip makers total. Large operations should be noted so we can improve the estimate for the chip maker. The running totalPromised delivery by December 2013
AsicMiner (internal): 1,000 Thash [7] [14]
AsicMiner (sales): 500 Thash
Avalon (rigs): 123 Thash
Avalon (chips): 274 Thash [1]
Bitfury (internal): 500 Thash [11]
Bitfury (Aug US & EU): 50 Thash [3] [9]
Bitfury (Oct US & EU): 255 Thash [3]
Bitfury (metabank): 32 THash
Bitfury (100/200TH mine): 200 THash [16]
Bitfury chips: 500 Thash (guestimate putting total Bitfury chips all forms & batches at ~ 1.5 PH/s or <200 wafers @ 55nm)
BFL (SC series): 3,000 THash [4] [15]
HashFast ("Oct"): 500 Thash [2] [6] (will not ship till early Nov but this reflects total of Batch 1, IceDrill, & BabyJet Upgrades)
HashFast (Nov/Dec): 2,000 Thash ??
KNC (Sept/Oct): 2,000 Thash [5] [8] [20]
KNC (Nov): 2,000 Thash
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Running Total: 12,934 Thash
Announced product but insufficient information to make an informed analysis (should be considered lower confidence and conservative estimators may wish to exclude completely) ActiveMining: ?? Thash [19]
AsicMiner ("next gen"): ?? Thash
Avalon ("next gen"): ?? Thash
BTCGARDEN: 1,750 Thash [17]
LabCoin: 53 Thash [18] DEAD?
xCrowd: ?? Thash DEAD?
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Running Total: 1,803 Thash
Post 2013 rollouts Cointerra: 2,500 Thash (January 2014) [10]
HashFast (MPP or reserve): 880 Thash (January 2014) [12]
BFL (monarch): ?? Thash (February 2014)
BitMine: 4,000 Thash (March 2014) [13]
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Running Total: 7,380 Thash
Presales Total 2013: 12,934 Thash
Announced Total 2013: 1,803 Thash
Running Total 2014: 7,380 Thash
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Combined Total: 22,117 Thash
1 TH/s = 0.14 mil difficulty
1 PH/s = 140 mil difficulty
1 million difficulty = 7 TH/s
1 billion difficulty = 7 PH/s
1 trillion difficulty = 7 EH/s
Upper limits on difficulty based on hardware efficiency: Miners are unlikely to mine when their electrical costs are higher than the value of BTC mined. This limit can be called the electrical break even point and is based on: a) the current exchange rate (USD per BTC) b) the hardware efficiency (J/GH ) c) the miner's electrical rate (USD per kWh) When hashrate/difficulty gets high enough it will cause the least efficiency miners to idle thus creating a sort of replacement cycle (i.e. x GH/s new efficiency hardware causes Y GH/s of older less efficient hardware to idle). This should slow growth significantly because the returns on new hardware will be low, miners will be exposed to the bad news of less efficient miners being forced to idle and X GH/s doesn't mean the hashrate only rises by (X-Y)/GH. It also illustrates the improbability of difficulty power growing exponentially over a long period of time like a year. For example 65 million difficulty gaining 75% per month for a year results in 50 billion difficulty. The electrical cost even at 1W/GH and $0.10 per kWh would >$250 per BTC. A related thread on the break even point is here: Break even difficulty by hardware efficiency (power cost = value of BTC)[1] https://docs.google.com/a/nacrypto.com/spreadsheet/ccc?key=0AiLYkKIHJaIsdHpIaGdUOWRYVUdncTNpNlVKbVhCbEE#gid=0 970,000 chips @ 282 MH nominal [2] 550 orders @ 400 MH nominal [3] Based on report that Dave (US distributor) sold out of their allocation of 300 full systems and 300 starter systems. Oct is not sold out but conservatively it will if/when Aug deliveries are made. I will assume that the EU distributor received an equal allocation (an assumption based on bitfury facing unknown demand and users in both markets). [4] http://bitcoin.stackexchange.com/questions/8577/how-much-asic-power-has-been-or-is-being-shipped-in-2013 Crude assumption based on distribution of wait list (hashing power per order) and number of orders. 2PH/s is guestimated based on (avg GH/s per order of known orders)*(num order numbers)*(1/3 to account for unpaid/test orders). Monarch is highly unlikely to ship in volume (if at all) in 2013 while upgrades cancel the existing 65nm order which would reduce the amount of 65nm pre-orders. [5] Guestimate. https://bitcointalk.org/index.php?topic=278384.msg2994436#msg2994436[6] https://bitfunder.com/asset/IceDrill.ASIC[7] http://www.dpcapital.net/blockchain/?hours=336[8] http://en.wikipedia.org/wiki/Occam's_razor[9] Reduced to 30 full systems in Aug for both US and EU distributors https://bitcointalk.org/index.php?topic=278384.msg3010364#msg3010364[10] http://www.coindesk.com/cointerra-cuts-price-of-terraminer-iv-bitcoin-mining-rig/ "In Dec" without a specific date can mean as late as 31 DEC. Given that and the tight schedule and the fact that even a small delay would push it into 2014 I included it in the 2014 group. Cointerra promises 20% additional hashrate if more than 30 days late so bump the amount from 2 PH/s to 2.5 PH/s. [11] https://ghash.io/[12] HashFast MPP will issue miners up to 4x their initial hashing power if 100% ROI is not acheived within 90 days. Even if MPP is not needed, HashFast would need the chips in reserve and any chips not paid out in the MPP are likely to be deployed as quickly as possible. [13] http://www.coindesk.com/bitmine-to-drop-4phs-of-asic-power-onto-bitcoin-network-before-april/[14] http://thegenesisblock.com/cointerra-expects-to-deliver-2-phs-of-asics-in-december/ (Numerous references, Cointerra 2PH/s, KNC 0.5 to 2 PH/s, AsicMiner 1 PH/s, Bitfury 0.5 PH/s, Avalon 0.32 PH/s [15] Upgraded BFL estimate from 2 PH/s to 3 PH/s https://bitcointalk.org/index.php?topic=278384.msg3029092 (see also the next two posts) [16] https://picostocks.com/docs/index/19[17] https://bitcointalk.org/index.php?topic=264696.msg3033042#msg3033042[18] https://bitcointalk.org/index.php?topic=283820.msg3046590#msg3046590[19] http://thegenesisblock.com/easic-announces-24-ths-hash-fast-miner-activemining-shares-move-70/[20] https://bitcointalk.org/index.php?topic=283820.msg3125451#msg3125451 |
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Well ASICMiner just gave mini rig buyers a punch in the gut.
Buy from BFL in August 2012. 1x mini-rig 1.5 TH/s @ 3000 BTC
Buy from ASICMiner in August 2013. 120x Eruptor Blades 1.5 TH/s @ 420 BTC
So buy from ASICMiner a year later, no pre-order stress, product will ship in days, spend 86% less, get the same hashing power and receive it sooner.
Things move fast in the mining world so specs only matter if the company can deliver as advertised when advertised. Those that trusted BFL @ 65nm paid the price, now they want to tell you 28nm will be different.
on edit: Fixed a typo 120 boards not 20. The typo seems obvious to me. 1,500 GH/s / 1.25 GH/s = 120 (not 20) boards. 420 BTC / 3.5 BTC = 120 (not 20) boards.
Originally posted in monarch thread to highlight that good specs mean nothing if while you are still waiting someone a year later undercuts it by 86%. I guess someone felt it was off topic. It isn't like the monarch is a new product with good specs and who's ROI is heavily dependent on if it can be delivered on spec and on time by the company who still hasn't delivered rigs that people paid 3,000 BTC a year ago that now have a street value of 420 BTC. Obviously this wasn't relevant at all.
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It is useful to know what the electrical break even difficulty of a device in estimating future hashrate growth of the network. A miner is unlikely to continue to mine for any extended period of time at a negative operating margin. The break even difficulty is the point where the electricity consumed by the mining equipment equals the value of the coins mined. At the break even point it will cost the miner the same amount to mine a coin as it would to purchase it. The hardware cost is not considered in the electrical break even point as once purchased the hardware is a sunk cost and the miner is very likely to continue mining as long as it shows a positive operating margin (electricity < value of BTC). Just because the difficulty is below the break even point doesn't guarantee the miner a positive return. The electrical break even point is based on three factors: a) the current exchange rate (USD per BTC) b) the price the miner pays for power (USD per kWh) c) the efficiency of the mining hardware (J/GH)https://bitcointalk.org/Themes/custom1/images/smflogo.gif Electrical break even point by hardware efficiency
Based on $100 BTC:USD exchange rate and $0.10 per kWh electrical power rate
Device Process Eff (J/GH) [1] Diff (mil) Hashrate (PH/s)
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GPU various 330.0 60 0.4
FPGA various 50.0 400 2.9
Avalon 110nm 8.8 [6] 2,400 17.2
ASICMiner 130nm 7.7 2,700 19.3
BFL (SC) 65nm 5.0 4,200 30.1
KNC 28nm 1.1 [3] 18,250 130.6
Bitfury 55nm 0.9 23,300 166.8
Hashfast 28nm ~0.8 [7] 25,100 179.7
Cointerra 28nm ~0.8 [2] 25,100 179.7
BFL (Monarch) 28nm ~0.8 [4] 25,100 179.7
Update (05/25/2014): I no longer have the time to research every new ASIC device. I have not seen a device that is significantly more efficient than 0.8 J/GH (at full clock) when measured at the wall and multiple devices have real world efficiency within +/-20% of that spec so it is a good place to start estimating difficulty. Remember miners are paying for full power consumption not just the power of the raw chip. The at the wall measurement is the only thing that matters. More efficient designs may eventually emerge but the low hanging fruit is now gone. If less than a year efficient of best device went from >8 J/GH to <0.8 J/GH. We aren't going to see a 1000% improvement in efficient in the next year. Even a 0.4 J/GH device (at the wall) would be an impressive improvement but only represents a doubling of the break even point. To calculate the break even difficulty at a different exchange and/or power rate use the following formula: Adjusted difficulty = base difficulty * (exchange rate / $100) * ($0.10/power rate) Examples: Avalon break even difficulty @ $200 exchange rate and same power rate. 2,400 * ($200/$100) * ($0.10/$0.10) = 4,800
BFL (SC) break even difficulty @ $0.15 power rate and same exchange rate. 4,200 * ($100/$100) * ($0.10/$0.15) = 2,800
Bitfury break even difficulty @ $200 exchange rate and $0.05 power rate. 21,000 * ($200/$100) * ($0.10/$0.05) = 84,000
Why J not W? Because J (Joule) is a measure of energy and W (Watt) is a measure of power. One Joule per second is one watt. You can't compare watts (energy over time) to a timeless value like Gigahash. Efficiency can be measured either in W per GH/s or J/GH bu not W/GH. It would be like saying a car gets 30 MPH per gallon or the spot price of gold is $1500 per ounce second. You can safely assume is someone writes W/GH they mean J/GH (or W per GH/s). I put this here because I have already gotten "corrections" by PM. Simple version: W per GH/s or J/GH are correct, W/GH is not.Why did you make this? I find it silly people have projections with difficulty going to 1 trillion or more (I think the highest I have seen is 200 trillion). At a mere 300 billion difficulty all current and proposed mining devices would be operated at a significant loss (assuming $100 exchange rate & $0.10 electrical rate). So at 1 trillion in difficulty even a Cointera rig would be converting $4 in electricity into $1 in Bitcoins. Anyone think that is likely? Significantly higher difficulty is going to require either more efficient hardware, a higher exchange rate, or the average cost of power for the network to decline. Notes:
[1] Numbers used are from mining hardware comparison where available or based on benchmarks reported by owners/manufacturer. For apples to apples comparison all units are based on wattage at the wall (including all system power and inefficiencies). For devices where total wattage at the wall is unavailable it has been estimated. For unreleased devices ("specs") the efficiency reported by manufacturer is used.
[2] Cointerra did not provide system efficiency "at the wall" however did indicate that chip wattage would be better than 0.55 J/GH, based on that I project the at wall efficiency to be ~0.7 J/GH. Updated to 0.6 J/GH at the chip and 0.75 J/GH at the wall based on official statement. This is based on the following assumptions. Chip power: 0.60 W per GH/s * 2000 GH/s = 1200W @ 0.785 VDC. DC to DC board PSU 90% efficient 1200W/0.9 = 1333W @ 12VDC. Balance of system controller & cooling/fans = 50W @ 12 VDC. Total system DC wattage 1383W @ 12VDC. ATX PSU 90% efficient 13832/0.9 = 1537W @ 120VAC. 1537W / 2000 GH/s = ~0.8 J/GH.
[3] Updated to 1.1 J/GH (https://bitcointalk.org/index.php?topic=170332.msg3307091#msg3307091). 455W @ 1 VDC running at 502 GH/s. Assume 90% DC to DC conversion and 90% AC power supply efficiency results in estimated 560W at the wall.
[4] The Monarch card is reported by BFL to use 350W. It is not clearly indicated if this is 350W at the chip or the card but I will assume the 350W is the total 12VDC wattage for entire card (to include one or more ASIC processors, host interface, card fan, and DC to DC board PSU. The balance of system is provided by the user so some assumptions are necessary to estimate efficiency at the wall. To be used in a PCIe slot the card requires a "traditional motherboard" with one or more PCIe slot, 100W min is assumed for system and fans. Total DC wattage for single card system is 450W DC. Assuming a 90% efficient ATX PSU 450W DC/0.9 = 500W @ 120V AC. 500W/600GH/s = ~0.8 J/GH. Actual wattage may be significantly higher depending on the components selected by the user.
[5] Given BFL's delivery track record and after the fact changes I don't feel comfortable making any prediction. I would recommend users be very conservative and pad the delivery timeframes provided by BFL.
[6] Due to multiple configurations power efficiency varies by number of modules, batch version, and PSU efficiency. The following efficiencies have been reported 9.4 J/GH (66 GH/s @ 620W), 8.8 J/GH (85 GH/s @ 750W), 8.5 J/GH (82 GH/s @ 700W).
[7] Based on reported efficiency at the wall of less than 350W and nominal performance of greater than 400 GH/s of the BabyJet with single hashing board.
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