Transaction length of Ethereum
many new users believe that the sole purpose of mining is to generate ether in a way that does not require a central issuer (see our guide "what is ether?"). It's true. The token of Ethereum is proced in the process of mining, with a mining rate of 5 Ethereum coins per piece. But mining is at least as important. Usually, banks are responsible for keeping accurate records of transactions. They make sure that money is not created out of thin air and that users don't cheat and spend money many times. However, blockchain introces a new way to keep records, the whole network instead of intermediary, to verify transactions and add them to the public ledger
Ethereum mining
although "no trust" or "trust minimization" monetary system is the goal, there are still people who need to ensure the security of financial records and ensure that no one cheats. Mining is one of the innovations that makes decentralized records possible. Miners have reached a consensus on the history of transactions in terms of preventing fraud (especially double spending on ether) - an interesting issue that hasn't been addressed before the decentralized currency works on the blockchain. While Ethereum is looking at other ways to reach a consensus on the effectiveness of the deal, mining currently keeps the platform together
how mining works
today, the mining process of Ethereum is almost the same as that of bitcoin. For each transaction, the miner can use the computer to guess the answer repeatedly and quickly until one of them wins. More specifically, the miner will run the unique header metadata (including time stamp and software version) of the block through the hash function (which will return a fixed length, unordered string of numbers and letters, which appears to be random), changing only the 'nonce value', which will affect the hash value of the result
if the miner finds a hash that matches the current target, the miner will be granted ether and broadcast the block across the network for each node to verify and add to their own ledger . If miner B finds the hash, miner a stops working on the current block and repeats the process for the next block. It's hard for miners to cheat in this game. There is no way to fake the work and come up with the right answer to the puzzle. That's why solving puzzles is called "proof of work."
on the other hand, others have little time to verify whether the hash value is correct, which is exactly what each node does. About every 12-15 seconds, a miner finds a stone. If the miner starts to solve the puzzle faster or slower than this, the algorithm will automatically re adjust the difficulty of the problem so that the miner can rebound to about 12 seconds of solution time
miners earn these ethers randomly, and their profitability depends on their luck and the computing power they put in. The specific workload verification algorithm used by Ethereum is called "ethash", which aims to require more memory, making it difficult to mine with expensive ASIC. Special mining chips are now the only profitable way to mine bitcoin
in a sense, ethash may have achieved this goal successfully, because dedicated ASIC is not available for Ethereum (at least not yet). In addition, as Ethereum aims to shift from proof of work mining to "proof of equity" (which we will discuss below), buying ASIC may not be a wise choice because it may not prove useful for a long time< However, Ethereum may never need miners. Developers plan to abandon proof of work, the algorithm currently used by the network to determine which transactions are valid and protect them from tampering to support proof of equity, which is guaranteed by token owners. If and when the algorithm is launched, proof of equity can become a means to achieve distributed consensus, and the consensus uses less resources.
Peter boockvar, chief investment officer of bleakey Consulting Group. I won't be surprised if the price of bitcoin drops to $1000 to $3000 in the next year, because bitcoin is not really relevant in this $19 trillion economy. Any commodity with a parabolic rise in price will usually fall back to the starting point< However, I'm not sure whether bitcoin will slow down or plummet suddenly
the implementation of loose monetary policy by central banks such as the Federal Reserve is the main reason for people's enthusiasm for virtual money. As interest rates graally return to the right track, virtual money will collapse. Once there is a crack in the virtual currency market, investors' attitude towards high-risk assets will also change, and the stock market may be injured. All this depends on the market psychology and has nothing to do with the economic fundamentals. "
Emma, the first one is scared to pee, so hurry to add a BTC
Soros
"as a currency, it should have a stable value storage function. The fluctuation of bitcoin in a day can be as high as 25%, which means that it is not feasible to pay wages with bitcoin
compared with the rapid collapse, the price of bitcoin may remain at a flat high. The reason why the outcome of bitcoin may be different is that some people, such as dictators, want to store wealth overseas through bitcoin
, however, can not change the nature of bitcoin as a typical bubble. It is based on misunderstanding as well as tulip fever. p> It seems that BTC is not reliable. But an alligator is an alligator. There's something in it, but it's not clear. I have an epiphany. You can do it yourself
Robert Shiller, Nobel Laureate in economics and professor of economics at Yale University, reminds me of the tulip craze that took place in the Netherlands in the 1640's. basically, bitcoin has no value unless some market participants believe it is valuable. In contrast, gold has some uses even if it is not used as an investment commodityup to now, people still pay for tulips, and sometimes the price is even quite high. In contrast, bitcoin is afraid to collapse completely and then be forgotten by the public. However, bitcoin may still exist for a long time, or even last for 100 years "
I don't understand, thank you
"Bitcoin and blockchain attract people's attention because they think it's an 'interesting experiment'". If it succeeds, it may change the world more than the Internethowever, it is also possible to fail, and the probability of failure is at least 20%. It is suggested that the amount of cryptocurrency held should be controlled within the range of bearable loss
the main reason for bitcoin's failure is that people put too much money into bitcoin and can't afford to lose money. "
raise so much money from all over the world just for an interesting experiment? Give me 0.005 BTC
dailyfx, a professional financial media of Fuhui group, said: "as the price of bitcoin failed to rebound to its historical peak in December, the price continued to fall. But objectively speaking, although the price of bitcoin fluctuates greatly, it will not fall by 50%. On the disk, the price has obvious support at the 11750 / 160 level, and the price rebounds above or after touching the support level; If the price falls below this point, it may continue to fall later
the price of Ethereum may break through the current slope area, but it will reach 1380 in the short term from the low point of 500 in December, or it will show that the bull rally is almost exhausted. Therefore, if the price does not fall in the later period, it will be more likely to consolidate. At present, the first support is at 863. If the price is still up, it will be a good opportunity for bulls to make another correction
in the later period, Ruibo currency may be in the trend of high consolidation or downward correction. As the price fell below the support level of 2.1577 yesterday, it continued to fall. In view of the sharp rise in prices last month, it is still unclear which point the current price will stabilize after falling or hitting. Therefore, it is still necessary to be cautious about the trading of Ruibo currency. "
The stock review has been changed to currency review. Brother, I recommend a coin circle of Guizhou Maotai Dennis gartman, founder of the "king of commodities" gartman news agency, said: "nothing can change my skepticism about bitcoin. Bitcoin will bring disaster to all those involved. At the same time, once this happens, investors will rush to the gold market. There is no doubt that bitcoin will fall below $5000. " It seems that it is necessary to collect some gold2. Good prediction
cesares, member of PayPal's board of directors
"the probability of successful bitcoin and blockchain experiments is more than 50%. But instry participants must be patient, because it will take another five to 10 years to achieve solid success
if the experiment is successful, the world will be very different. By then, the value of a bitcoin will reach one million dollars. Therefore, most people in the world will want to buy bitcoin in the price range of $14000 or $20000. "
previously, it was said that the probability of failure is at least 20%. Now it is said that the probability of success is more than 50%. You have all the good words and bad words. Do you owe a BTC
analyst van Petersen of Shengbao bank
"the price of bitcoin is likely to reach $50000 to $100000 in 2018. Digital currencies other than bitcoin will also soar
first of all, you may think that the price of bitcoin has been properly adjusted. After all, it has dropped by 50%, which is healthy. But we haven't seen the full effect of futures contracts
this year, Ethernet may surpass bitcoin, and it will appear later than bitcoin, but it has a more unified leadership position than bitcoin. "
He was right about this guy last time. When the transaction price of bitcoin was below $900 in December 2016, he predicted that bitcoin would reach $2000 in 2017. As a result, bitcoin exceeded $2000 in May 2017. However, it is predicted that eth will surpass BTC. Well, it's not impossible for the second child to seek power to usurp the throne and kill the first child. It's just difficultMichael Graham, analyst at canaccord genuity, an investment company, said, "one of our themes is that more institutions will enter the cryptocurrency market in 2018. The number of institutional investment procts related to bitcoin is increasing. Regulators will approve a bitcoin Trading Fund in the second half of this year or early 2019
I confirm that this year, the public will see IPOs from some encryption companies and more widely from blockchain companies. "
it's better for me to break the news! CBOE applied for six cryptocurrency ETFs at the end of 2017 and may go online in 2018. What the hell is this? That is to say, it increases the opportunity for institutional investors to have close contact with cryptocurrency and opens channels for professional speculators
Tom Lee, co-founder of fundstrat and super bull of bitcoin, predicts that the bottom of bitcoin will be about $9000. If it falls to this position, we will buy strongly, and $9000 is the best time to enter this yearit is estimated that bitcoin will rise to US $25000 by the end of the year and US $125000 by 2022
bitcoin has experienced many ups and downs, but it always stands back to the previous high point, and the low point becomes a good opportunity to buy
since the middle of 2016, bitcoin has risen more than 75% for five times and plummeted more than 25% for six times. Similar ups and downs in the stock market will take several years, but the virtual currency world can do it in a few months
also optimistic about three kinds of virtual currency. The first is eth, which has the function of smart contract and has a bright future. It is estimated that eth will rise from the current US $1000 to US $1900 at the end of this year. The second is etc, a virtual hybrid of bitcoin and Ethernet, which will rise from the current $25 to $60 at the end of the year. The third is the virtual currency Neo developed by China, whose price will rise from US $114 to US $225 at the end of the year. "
Say! How much did the project give you? I'd like to introce you to Mr. Ali, chief investment officer of blocktower capital, a cryptocurrency investment company; Ari Paul"at some point in 2018, the price of bitcoin can be as low as $4000 or as high as $30000."
Go awayJulian hope, co-founder and President of tenx
"bitcoin may break the $60000 mark in 2018, but it may also drop to the bottom of $5000, but it's not sure which one will come first, surprise or scare."
go away + 1
Nick colas, analyst of datatrek research, a data analysis organization, said, "the fluctuation of bitcoin in 2018 will exceed that in 2017, and the fluctuation may range from US $6500 to US $22000, all of which are reasonable valuations. And $14035 would be a reasonable median. In addition, there will be four price collapses of bitcoin in 2018, with the magnitude of each collapse being about 40% or more. "
are there still four opportunities for bottom selling and position increase this year
George Tung, co-founder of cryptos r us and a veteran of cryptocurrency investment, will we see another virtual currency whose market value exceeds that of bitcoin? Yes, I believe it is absolutely possible in the next three to five years. Or as soon as three years, there will be competitors who can compete with bitcoin. "the 3000 year old little demon wants to kill the 7000 year old demon? It's still tender
Lex Sokolin, global head of financial technology strategy, automous research, said, "the currency circle may usher in a new round of" furcation frenzy "in 2018, with a maximum of 50 furcation times!" Pro, we are here to talk about the price. What do you mean by having a second childin front of the article: the video version is slightly different from the text version. If you want to see my affectionate interpretation, please see the video version (meow understands blockchain phase 22 | sharding: Ethereum is too slow, "disk" him!), The logic of thinking is strange. Please see the extended version
recently, Ethereum has shown an overwhelming positive trend e to the Constantinople upgrade, while Ethereum's upgrade road is like upgrading and fighting monsters, falling into rabbithole. No one knows how deep the hole is. Since it is a long way to go, it is of vital importance to make every step well and accurately. After overcoming this difficulty, Ethereum's next technical difficulty, sharding fragmentation, has been put on the table again. This issue of "meow understands blockchain" will take you into sharding, the magic weapon that makes Ethereum fast
what is sharding
slicing technology is not a new concept. At first, it is an optimization scheme for large central database. Specifically, it divides the data in large database into many shards according to certain rules, and then stores these data in different servers to rece the data access pressure of each server, So as to improve the performance of the whole database system
let's take a small popular example:
for example, meituan, Didi taxi and other software that we often use can be divided according to the "city". Because the data of different cities do not need to communicate, the data of different cities can be stored in different databases, so that the database server can be deployed to the nearest node from the corresponding city, Can also improve the speed of access, why not do it
from the above example, we should have a preliminary understanding of the concept of fragmentation. What about fragmentation in blockchain scenarios
taking Ethereum fragmentation as an example, in the original single chain system, the overall performance of the public chain depends on the performance of a single node. After fragmentation, each node only needs to undertake the work of the whole network, and each fragmentation works in parallel. According to vitalik, each shard is like a separate galaxy, and each fragmentation is like an independent universe, In this way, the efficiency will be improved naturally! Originally, the total network TPS of Ethereum chain was about 20. Now, if it is increased to 100 pieces, the total network TPS can be increased to 2000. Similarly, the total network capacity will be increased to 100 times of the original
"each node only needs to undertake part of the work of the whole network", which will lead to several major problems. 1. How to determine which piece of work this node is responsible for? 2. Which transactions should be classified into which segments? 3. Does each node only need to store its own transaction information (ledger)
according to the implementation of the above problems, we can divide the fragmentation into three types: network fragmentation, transaction fragmentation and state fragmentation
Network fragmentation: how to divide the nodes of the whole network into different partitions
transaction segmentation: how to divide the whole network transactions into different segments
State fragmentation: how to make each node only maintain the account book in its own fragmentation without affecting the security of the whole system
the difference and connection between main chain and fragmentation chain
we have understood the types of fragmentation, so what's the difference between main chain and shard chain
turn left | turn right
the realization of Ethereum fragmentation is a long process. Even vitalik himself said that it will be graally realized by stages. We'd better look forward to whether fragmentation can move from theory to practice
2. Project clone to local, project address:
3. Execute submole updata -- init
4. Install script in the directory_ Deps.bat is copied to the root directory and executed. This step will download hunter, boost, libjson, etc. to Disk C, which takes a long time. Please wait patiently
5. Go to the directory of the project and create the build subdirectory,
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address
hash-> Data field of Ethereum transaction
broadcast transaction (chain customer)
at the same time, data storage on the chain can be realized in two ways:
1. After data is organized in a certain form, it is put into the data field of transaction, which is not very flexible, but relatively simple
2. Write the contract and store it in the state variable of the contract.
EOS can be understood as enterprise operation system, which is a blockchain operating system designed for commercial distributed applications. EOS is a new blockchain architecture, which aims to extend the performance of distributed applications. Note that it is not a currency like bitcoin and Ethereum, but a token based on the EOS software project, known as blockchain 3.0. The main features of EOS are as follows:
1. EOS is a bit similar to Microsoft's windows platform. By creating a developer friendly underlying platform of blockchain, it supports multiple applications running at the same time and provides the underlying template for the development of DAPP
2. EOS solves the problems of delay and data throughput by means of parallel chain and dpos. EOS can process thousands of data per second, while bitcoin has about 7 transactions per second, and Ethereum has 30-40 transactions per second
3. There is no service charge for EOS, and the general audience is more extensive. The network and computing resources needed to develop DAPP on EOS are allocated according to the proportion of EOS owned by developers. When you have EOS, it is equivalent to having computer resources. With the development of DAPP, you can lease your EOS to others. From this point alone, EOS has a wide range of value. To put it simply, if you have an EOS, it is equivalent to having a set of rent to collect rent for others, or having a piece of land to rent for others to build a house< br />
generally, the permissions are very low, so you can only open and modify the files in the Apache Web folder. You can't call programs anywhere else
you use the login user's permission in Linux, which is also for security.
The range of Ethernet frame bytes should be 72 ~ 1526
the Ethernet frame format is shown in the following figure:
extended data:
the data packets on the Ethernet link are called Ethernet frames. The starting part of Ethernet frame consists of preamble and frame start character. It is followed by an Ethernet header, which indicates the destination address and source address by MAC address. The middle part of the frame is the packet (such as IP Protocol) containing other protocol headers loaded by the frame. The Ethernet frame ends with a 32-bit rendancy check code. It is used to check whether the data transmission is damaged
a frame starts with a 7-byte preamble and a 1-byte frame start character. Before fast Ethernet, the bit mode of this part of the frame on the line was 10101010 10101010 10101010 10101010 10101010 10101010 10101010 10101010 10101010 10101011
because the lowest bit is transmitted first (LSB) when a byte is transmitted, the corresponding hexadecimal representation is 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 D5
10 / 100M network card (miiphy) transmits 4 bits (one and a half words) at a time. Therefore, the preamble will be 7 groups of 0x5 + 0x5, and the frame start character will be 0x5 + 0xd. 1000m network card (gmii) transmits 8 bits at a time, while 10Gbit / S (XGMII) PHY chip transmits 32 bits at a time
note that when described as octet, seven 01010101 are transmitted first and then 11010101 are transmitted. Since the lower four bits of the 8-bit data are transmitted first, 0101 of the frame start character is transmitted first, and then 1101 is transmitted
all four Ethernet frame types can include an IEEE 802.1Q option to determine which VLAN it belongs to and its IEEE 802.1p priority (QoS). This encapsulation is defined by IEEE 802.3ac and expands the frame size from 64 bytes to 1522 bytes (Note: it does not contain 7 leading bytes, 1 byte frame start character and 12 frame spacing bytes)
the IEEE 802.1Q tag, if it appears, needs to be placed between the source address field and the Ethernet type or length field. The first two bytes of this tag are the tag protocol identifier (TPID) value 0x8100. This is the same as the position of the ether type / length field of the frame without label, so the ether type 0x8100 represents the frame with label, while the actual ether type / length field is placed after the q-label
TPID is followed by two bytes of tag control information (TCI) IEEE 802.1p priority (QoS) and vlanid). After the Q tag is the usual frame content