Ethereum II

1.

blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum

blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies

blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block

extended data

according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:

1. The blockchain with the whole network open and without user authorization mechanism is called public chain

2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain

3. All the nodes in the network are in the hands of one organization, which is called private chain

alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain

blockchain features

1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain

2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent

3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention

4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes

5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously

2. The first generation of digital currency generally refers to bitcoin, which is the first digital currency as well as the overlord of digital currency instry
the second generation of digital currency generally refers to Ethereum, Leyte, doggy and other counterfeit coins
the third generation of digital currency refers to wiki chain and quantum chain.

3.

Bitcoin is not the only digital currency on the Internet. There are also ripple, stellar, litecoin, Ethereum and other digital currencies. Of course, the most popular is still bitcoin. But many times, some developers, entrepreneurs or enterprises will let us know that we need better digital currency. A programmer named Jed McCaleb, the father of electric donkeys, developed the reborn coin, which should be better than the bitcoin. Later, he launched the star coin, which is better than the reborn coin. What is more gratifying is that he is not fighting alone

now there is a trend that the instry hopes to develop a technology that enables all these online digital currencies to flow to each other, which means that you can transfer money freely in different online digital currency systems in the future. This technology is known as "interleaver protocol (ILP)", initiated by ripote. However, in recent months, that is, after the company released this idea, they also got the support of many famous companies in the instry, including Microsoft and the world wide web. Obviously, Ruibo currency company wants to set the technical standard of digital currency on the Internet. They want to develop a single global network, which can not only unify all digital currencies, but also unify all enterprises and indivials who use these digital currencies

"we want to be on a higher level and extract the differences between various digital currencies," said Stephen Thomas, chief technology officer of ripple. "We are trying to develop a global standard for payment."

with the launch of this agreement, we hope to enable more people to use online digital currency, expand the scope of use of online digital currency, and let us transfer funds more efficiently. This is actually the goal of many existing projects. For example, the original intention of the design of reborn currency and star currency is to allow users to transfer money to these two digital currency accounts in any currency, and to enable these two digital currencies to be converted into other currencies correspondingly. You can send bitcoin, and then the other party gets it. You can also send us dollars, and the other party will get dogecoin. However, for businesses and the developer community, there are restrictions on their use of these ledgers, so there are some problems because you can't transfer money from one payment network to another. Now, however, the interleaver agreement hopes to change that

to some extent, after ten years of efforts, they hope to develop a new network protocol, which is commonly known as "money Internet". If we go back to the early 1990s, we know that the famous Marc Andreessen founded the Netscape web browser. Now, the project hopes to play a similar role. They want to establish a standard way to send funds on the Internet. In fact, the original Hypertext Transfer Protocol (HTTP, which defined the basic standard of the network) contained code for payment. But this code has never been used. In recent years, many companies (such as coinbase, a bitcoin exchange, and stripe, a company that helps enterprises accept various online digital currencies) are at least trying to create a conventional standard for online digital currencies. In the future, we hope to be able to send and receive money online, just like sending short messages or e-mails. However, we still have a long way to go to this paradise, but at least now we are in the right direction

4. All are the underlying consensus algorithms of blockchain, power consumption of pow. The dpos used by EOS has 21 super nodes, but it's always bribed to vote, so now dpos is basically labeled as a centralized blockchain. I also think it's against the spirit of blockchain. Por consensus protocol is a new consensus mechanism proposed by Baker chain. It is hatched by Whitfield Diffie's cryptic labs, the father of public key and winner of Turing prize. This lab is the world's best network security lab, and Baker chain is the best network security lab in the world

5.

Ether coin

related introction:

eth is a kind of digital token of Ethereum, which is regarded as "bitcoin version 2.0", and uses the blockchain technology "Ethereum" different from bitcoin

The system of

Ethernet coin is the most widely used public blockchain system supporting complete application development. Compared with bitcoin, Ethereum belongs to the category of blockchain 2.0, which is a new blockchain system designed to solve some problems of bitcoin network

extended data

related background:

the emergence of Ethereum is to help users more easily use blockchain technology for application design. According to BARTLIN, the purpose of Ethereum is to create a more general blockchain platform, which can allow users to easily create blockchain based applications and avoid users having to build a blockchain in order to create a new application

generally speaking, the previous blockchain was only a single tool or at most a combination of multi-functional tools, while Ethereum is the smartphone of blockchain, and users can use the smartphone to build any "application" they need. Therefore, BARTLIN said that the application of blockchain is not limited to cryptocurrency. It has great potential and can be applied to all walks of life. It can bring significant benefits to enterprises and organizations of all sizes

source of reference: Internet - Ethernet currency

6. Bitcoin is one of the most representative virtual currencies. A group of virtual currencies headed by bitcoin will exist for a long time. It will not replace the current legal currency. It will exist independently of the legal currency. It does not belong to any country. Some virtual currencies are reached by some people first, and then graally form a wider circulation because of its value, If more people reach this consensus, they will have the value of existence in the end. Of course, most of the virtual currency has no value, it is a kind of air currency. If a currency wants to exist for a long time, it must go through a long period of ups and downs, and constantly dig out its greater use value. Only in this way can it be a virtual currency with real value< There are two ways to invest in virtual currency:

first, mining is the only way to obtain some virtual currency such as bitcoin. After professional mining equipment is connected to the mine pool, bitcoin is obtained through a lot of calculation. Besides the cost of mining equipment, there is also the most important electricity cost. Mining machine is a computer, The required power consumption is not small, and the electricity cost needs to be continuously invested for a long time, so the mining income should be above the electricity cost, so the investment in mining is feasible. It can be divided into the following situations:

1. The cost of electricity is very low or electricity is free, there are some special instries that can enjoy lower electricity prices than ordinary residents, or build their own hydropower plants, etc...

2. The mining output is fixed. Friends who have g mines will know that one of the major obstacles in mining is the difficulty of computing power. Take bitcoin as an example, the number of bitcoins is fixed, but with more and more people digging, the output will be lower and lower, and then the income will be lower and lower. If the electricity cost is fixed, then when the output income is equal to the electricity cost, the output income will be lower and lower, Mining is no longer feasible

3. The currency price is stable. Mining will have the problem of accounting return to the current cycle: output * current currency price electricity cost = net income

mining machinery cost / net income = return to the current cycle

we mentioned that the output is fluctuating, and the currency price is also fluctuating, but we can choose to sell coins under the condition of our own income, which requires a large amount of personal reserved funds, Because once you choose to hoard money, it means that you will not generate revenue before the money price reaches the ideal price, but you need to put in a fixed electricity cost< In the second half of 2017, the virtual currency ushered in a bull market. Before that, whether you buy bitcoin or Ethereum, it's easy to double your assets, but it's a transition to the market in 2018, Most of the quilt cover, and fry money overnight rich have, overnight bankruptcy also have. Similarly, currency speculation can be divided into the following situations:

1. The most common way of currency speculation is to buy at a low price and sell at a high price. It's easy to make money in a bull market. As long as you are optimistic about the currency and find a low price to buy, you can sell by yourself (I suggest that the mainstream currency is better)

2. In private placement, some newly issued but not yet listed coins will be privately raised, that is, crowdfunding. At the beginning, it is a low price, which may be a few cents or even a few cents. In the process of issuing and listing, there are unlimited possibilities. It is very possible to double or even ten times the price, but there are also some cases that can not be launched on the platform or broken, So these are not worth money in hand, just a series of figures. At the same time, private placement is not allowed by the state

3. Contract trading, which is the trading object or subject matter of futures trading, is a standardized contract formulated by the futures exchange to deliver a certain quantity and quality of goods at a specific time and place, and the futures price is achieved through open bidding

generally speaking, contracts can be bought up and bought down. When the market is in a bear market, buying up and currency price rising can bring benefits; Buying down and currency price falling will bring profits. Meanwhile, bear market fluctuation is small, and leverage can be added to increase the amount of capital

therefore, with the development of virtual currency and the recognition of many countries, virtual currency will not only be mentioned in real life, but it is also reliable to invest in virtual currency. However, in different periods, facing different market, there will be different ways of investment. If you choose to hoard money at a high price in a bull market, it is not reliable, So whether you invest in virtual currency depends on how you invest

7. Blockchain is an important concept of bitcoin. It is essentially a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of information about bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block.

8. There's no possibility of pushing it down. Xiaomi's plot will happen before he finally crosses the repeater. The only known thing that can develop later is Xiaomi, who will fall in love only after he finally comes back. As for you want to increase the model value in the end, there's no way. Unless you install DLC, unless your generation has a tweet Liana or ash, you can only push one

9.

This is a Linux system IP address configuration command. The specific meaning is:

set the IP address of the system to 192.168.0.2; The subnet mask is 24, that is 255.255.255.0; The broadcast address is 192.168.0.255; The name of NIC device is eth0

all computers in the network must set a unique IP address to communicate normally. Because of this unique address, users can select the objects they need from thousands of computers efficiently and conveniently when they operate on networked computers

The IP address is just like our home address. If you want to write to a person, you need to know his or her address so that the postman can deliver the letter. A computer sending information is like a postman. It must know the only "home address" to avoid sending the letter to the wrong person. But our address is expressed in words, the address of the computer is expressed in binary numbers

eth0 is the name set by the system for the network card. If there are al network cards or multiple network cards, there will be names like eth1 and eth2. The name can be set artificially. It is the unique name of the network card in the current computer system

< H2 > after modification, you can use ifconfig command to check whether the modification is successful

10. What is asset currency? The first generation of digital currency based on blockchain is bitcoin BTC, which solves the problem of human digital consensus. At present, it is worth 100 billion yuan; The second generation is the technology currency represented by Ethereum eth, which solves the efficiency problem of human large-scale cooperation. The current currency value is 500 billion; The third generation is the asset currency represented by currency plus currency BIC, which solves the problem of fair redistribution of human wealth. The future currency value will exceed 5 trillion.