Official inquiry of Ethereum DAG
bitcoin uses SHA-256 encryption algorithm. When mining, it competes with computing power. In order to improve computing power, bitcoin has gone through four stages: CPU mining, GPU mining, FPGA mining and now ASIC mining machine mining, and the degree of specialization is getting higher and higher
Ethereum uses the ethash encryption algorithm. In the process of mining, it needs to read the memory and store the DAG file. Because the bandwidth of each read memory is limited, and the existing computer technology is difficult to have a qualitative breakthrough in this problem, so no matter how to improve the computing efficiency of the computer, the memory read efficiency will not be greatly improved. Therefore, in a sense, Ethereum's ethash encryption algorithm is ASIC resistant.
different encryption algorithms lead to great differences in mining equipment and computing power between bitcoin and Ethereum
at present, bitcoin mining equipment is mainly ASIC mining machine with a very high degree of specialization. The maximum computing power of a single mining machine is 110t / s, and the scale of computing power of the whole network is more than 120eh / s
the main mining equipment of Ethereum is video card miner, and there are very few specialized ASIC miner. On the one hand, the "ASIC resistance" of Ethereum mining algorithm improves the threshold of developing ASIC miner. On the other hand, after Ethereum is upgraded to 2.0, the consensus mechanism will be transformed into POS, and the miner can not continue mining
compared with the ASIC miner, the graphics card miner has two orders of magnitude difference in computing power. At present, the computing power of mainstream graphics card miner (8 cards) is about 420mh / s, and that of Ethereum is about 230th / s.
from the time dimension of the past two years, bitcoin's computing power of the whole network is growing rapidly, while Ethereum's computing power of the whole network is growing relatively slowly
The ASIC mining machine of
bitcoin is monopolized by several major mining machine manufacturers, and miners can only buy it from the market; Although the graphics card miner of Ethereum is also manufactured by a special miner, the miner can buy accessories from the market and assemble them according to his own demand
Change: the characteristics of blockchain disintermediation, consensus mechanism and non tampering can increase the efficiency of data flow, rece costs, monitor the real situation of assets in real time, and ensure the trust of all parties in the transaction chain on the underlying assets.
1. Login Z? B account, click finance
2. Select the abbreviated currency of quantum currency and click "recharge". After creating an account, the system will automatically assign you a recharge address to which you can recharge
3. After network confirmation, you can get to your account.
let's talk about the problem of high concurrency. High concurrency is a problem in the computer field. In short, the problem of high concurrency is that the system cannot run multiple tasks at the same time smoothly
many tasks are running at the same time, and a large number of users rush in. The system can't bear so many tasks. There will be high concurrency problems, and your system will be stuck, just like the 12306 system is always stuck ring the Spring Festival, which may be caused by the high concurrency problems
the traditional Internet still has the problem of high concurrency, which naturally exists in the blockchain network. After all, the maturity of the blockchain is still far behind that of the traditional Internet. However, if there is no safe, reliable and efficient public chain, the development of the whole blockchain instry will be seriously restricted, and the application landing is empty talk
in this context, DAG technology has been proposed, DAG's full name is "directed acyclic graph", which is translated into "directed acyclic graph" in Chinese
What's the matter with DAG directed acyclic graph and what role it can play? Let's explain< Dag: a new data structure
DAG, Chinese name is "directed acyclic graph", literally, "directed & quot; That is to say, it has direction,
"no loop" means that it has no loop and cannot form a closed loop. Therefore, DAG is actually a new type of data structure. This data structure has direction and can not form a closed loop
in terms of traditional blocks, we always take "block" as the unit, and a block often contains multiple transaction information. In DAG, there is no concept of block. Instead, it takes "unit" as the unit. Each unit records the transaction of a single user. The unit is not a block, but a transaction. In this way, the time of packing blocks can be saved
in short, the biggest difference between blockchain and DAG directed acyclic graph is that blockchain is one block after another to store and verify the distributed ledger of transactions, while DAG regards each transaction as a block, and each transaction can be linked to multiple previous transactions for verification< Second, the working principle of DAG
in the traditional blockchain, take bitcoin as an example, it is a single chain structure. The blocks are arranged according to the time stamp sequence (as shown in Figure 1), and the data is recorded on a main chain. To use an inappropriate metaphor, this "single chain" structure is a chain arranged word by word
there is only one single chain in the blockchain, so it can not be executed concurrently when the block is packaged. The new block will be added to the original longest chain, and all nodes will follow the longest chain and continue to spread infinitely in the order of timestamp. For DAG, each newly added unit is not only added to one unit of the longest chain, but also to all previous units (as shown in Figure 2)
for example: suppose I publish a new transaction, and there are two effective transaction units in DAG structure, then my transaction unit will actively link to the previous two at the same time to verify and confirm until it is linked to Genesis unit, and the hash of the previous unit will be included in its own unit
in other words, if you want to make a transaction, you have to verify the previous transaction, specifically several transactions, according to different rules. This verification method enables DAG to write many transactions asynchronously and concurrently, and finally forms a topological tree structure, which greatly improves the scalability
according to DAG directed acyclic graph, every transaction is directly involved in the maintenance of the whole network. When the transaction is initiated, the whole network is broadcast directly, skipping the block packing stage. In this way, the time of block packing is saved, and the transaction processing efficiency of the blockchain is improved
with the increase of time, the blockchains of all transactions are interconnected to form a graph structure. If you want to change the data, it is not just the problem of several blocks, but the data change of the whole block diagram. Dag is more complex and difficult to change
to sum up, DAG, as a new type of decentralized data structure, belongs to a kind of generalized blockchain and has the attribute of decentralization. However, the differences between the two are as follows:
the composition unit of blockchain is block and the composition unit of DAG is TX
blockchain is single threaded, DAG is multi-threaded
all transactions of blockchain are recorded in the same block, and each transaction of DAG is recorded in each transaction separately
blockchain needs miners, DAG doesn't need miners< (3) representative of DAG: iota is undoubtedly the most famous representative project of DAG. It can be said that it is precisely because iota, the currency, broke into the fourth place in market value in the second half of 2017 that people really realized its underlying technology: DAG directed acyclic graph
iota puts forward the concept of "entanglement" on the basis of DAG directed acyclic graph. In iota, there is no concept of block, and the minimum unit of consensus is transaction. Each transaction will refer to the past two transaction records hash, so that the previous transaction will prove the legitimacy of the past two transactions and indirectly prove the legitimacy of all previous transactions. In this way, a small number of nodes such as miners in the traditional blockchain are no longer needed to verify transactions and package blocks, so as to improve efficiency and save transaction costs< Fourth, the current situation of DAG
although DAG directed acyclic graph can make up for some disadvantages of traditional blockchain in theory, it is not mature at present, and it has been applied to the field of digital currency for a short time
it did not take as long as 10 years to verify the security of the whole system as bitcoin did, nor did it achieve a wide range of application scenarios as Ethereum did. However, some voices now propose to adopt the data structure of "traditional blockchain + DAG", but there is no outstanding case, so I won't say more here
to sum up, in this section, we introce the derivative technology of blockchain: DAG directed acyclic graph, which is a new data structure, and can significantly improve the efficiency and power of blockchain transaction processing.
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generally, high-end and high-performance graphics cards are needed for mining, and mining consumes the performance of graphics cards
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it is recommended to replace or check the driver version of the graphics card to see if it is the same. If it is still the same, it is recommended to re install the system and use the latest version of win10
