Ethereum answers
a brief history of etheric Classics (etc)
etheric classics began with an unfortunate event
in May 2016, the decentralized autonomous organization (DAO) held a token sale with the goal of establishing a blockchain based venture capital to fund future decentralized applications (dapps) in the Ethereum ecosystem
basically, Dao is a complex smart contract that operates in a decentralized way - computer code that automatically performs tasks between multiple parties when conditions are met
despite its ambitious goals and successful token sales, Dao's code has a major vulnerability that allows attackers to steal eth from decentralized organizations
the attacker took advantage of this vulnerability in June 2016, triggering the infamous Dao hacking event, and maliciously stole eth worth about US $50 million
there is no doubt that Dao hacking has shocked Ethereum community and made eth price drop from $20 to $13
after the Dao hacking, the Ethereum community has to choose from three options
< UL >do nothing and try to bear the consequences of the attack; Or
start soft bifurcation to recover funds; Or
deploy a hard fork to recover the lost eth
both soft and hard bifurcations are significant network upgrades. However, soft fork allows users who are not upgraded to communicate with upgraded users, while hard fork is not backward compatible with previous versions
as developers realize that deploying soft forks will expose the network to distributed denial of service (DDoS) attacks, Ethereum community decides to initiate hard forks to recover the funds lost in Dao hacking attacks
although this scheme is supported by most people, a small number of people in Ethereum community oppose it. They think that "code is the law" and blockchain network should be unchangeable
the failure of both sides to reach an agreement on the solution eventually led to the fragmentation of Ethereum blockchain
those who tried to recover the lost eth chose the hard fork and opened the Ethereum (ETH) blockchain as we know it today, while another group stayed on the original Ethereum classic (etc) chain
what problems does ethereal classic solve Ethernet classic (etc) is a blockchain platform that allows developers to deploy smart contracts and dapps although this function is the same as Ethereum (ETH), etc blockchain has two main differences first of all, Ethereum classic community opposes tampering with distributed ledger and supports the view that "blockchain network cannot and should not be modified" secondly, although there is no rigid upper limit on the total supply of eth, it is allowed to create 230 million etc at most by adopting the monetary policy of constant supply as a bonus item, ethereal classic launched Atlantis hard bifurcation last year to increase the interaction with Ethereum and improve the privacy protection of transactions through ZK snarks the trading platforms recommended by etc hot money, okex, AAX, etc
If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records
the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:
< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});
Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query
recommend a practical introction, you can see: Ethereum tutorial
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.
this may be found from the contract law and the losses caused by violation,
every day, you can 1. Brush your circumference by swimming, running on the beach and climbing stairs (at the corresponding location) 2. Brush your performance in EGlu (fishing / farming / mining, 3. Dating and developing relationships with lovers 4. Participating in competitions / watching competitions 5. Participating in various activities ring festivals (arug / parliament / Wedding / funeral, etc.) 6. If PC is a child, it has to go to school on the corresponding day 7. Picking grass / flowers / insects / shells when it's really boring
the condition for joining a royal family is to marry someone who inherits the throne in a very early order. The Empress Dowager's words are easy to be kicked out of the royal family. The premise is that the other party is alt unmarried. At most, people who are still children can develop friendship.
in 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 examples, 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