Ethereum DAG size

1. GPU mining

Hardware

algorithm is difficult to solve in memory. In order to make DAG suitable for memory, each GPU needs 1-2gb of memory. If you get an error prompt: error GPU mining. GPU memory fragmentation? It means you don't have enough memory. GPU mining software is based on OpenCL, amd GPU will be faster than NVIDIA GPU of the same level. ASIC and FPGA are relatively inefficient, so they are blocked. To get OpenCL for chip integration platform, try:
amd SDK OpenCL
NVIDIA CUDA OpenCL
Ubuntu Linux settings

for this quick guide, you will need Ubuntu 14.04 or 15.04 and fglrx image driver. You can also use NVIDIA drives and other platforms, but you have to find your own way to get an effective OpenCL installation, such as genoil's ethminer fork
if you are using 15.04, go to & quot; Software and updates 〉 extra drives & quot; Set to & quot; Use the video driver & quot; from fglrx for AMD graphics accelerator
if you are using 14.04, go to & quot; Software and updates 〉 extra drives & quot; Set to & quot; Use the video driver & quot; from fglrx for AMD graphics accelerator;. Unfortunately, for some people, this method may not work, because there is a known program error in Ubuntu 14.04.02 that will prevent you from switching to the exclusive graphics drive necessary for GPU mining
therefore, if you encounter this program error, go to & quot; "Software and update" update & quot; Select & quot; Pre release reliable update proposal & quot;. Then, back to & quot; Software and updates 〉 extra drives & quot; Set to & quot; Use the video driver & quot; from fglrx for AMD graphics accelerator;. After restarting, it's worth checking that the drive is now properly installed (for example, by going to & quot; Additional drives & quot;)
no matter what you do, if you are using 14.04.02, once installed, do not change the drive or drive configuration. For example, the use of aticonfig – initial (especially the - F, - force option) will & quot; Destruction & quot; Your settings. If you accidentally change the configuration, you will need to uninstall the drive, restart, install the drive again and restart.

2. At the top of Ethereum is DAPP. It exchanges with the smart contract layer through Web3. JS. All smart contracts run on EVM (Ethereum virtual machine) and use RPC calls. Below EVM and RPC are the four core contents of Ethereum, including: blockchain, consensus algorithm, mining and network layer. Except DAPP, all other parts are in the Ethereum client. The most popular Ethereum client is geth (go Ethereum)

3.

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

4. At present, most of the mainstream Ethereum mining machines in the market come from bitmainland and Jianan Yun. However, with the decline of Ethereum's price, the profits brought by mining have been very meager. Investors can choose to invest in Ethereum on the digital currency exchange. At present, the mainstream digital currency transactions in the market are all coin security, fire coin network, bitnet, etc.

5. 1、 Recharge
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.

6. Currency tiger global transaction fees platform currency can also be halved, overall not bad

7. DAG (directed acyclic graph) is a common data structure in the computer field. Because of some characteristics brought by the unique topology structure, it is often used to deal with dynamic planning, search for the shortest path in navigation, data compression and other scenes. Since 15 years ago, the concept of blockchain has been singled out. Before that, blockchain was just a data structure in bitcoin technology, and when block and chain were connected in Nakamoto's white paper, it was just a chain of blocks. With the emergence of the concept of Ethereum decentralized computer, many people began to call Ethereum blockchain 2.0, while bitcoin was classified as blockchain 1.0. As for blockchain 3.0, in order to seize the naming right of blockchain 3.0, it may be DAG.

8. Dag can find a good balance in decentralization and scalability, which also follows the traditional values of blockchain.

9. We say that the blockchain is not mature at present, and there are various problems, such as slow processing speed, high handling charges, security risks and so on. These are the most intuitive experience of users, and the experience is not very good. Another problem of blockchain is high concurrency
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.