Ethereum open source framework

1. Ethereum is a new and open blockchain platform, which allows anyone to build and use decentralized applications running through blockchain technology in the platform
just like bitcoin, Ethereum is neither controlled nor owned by anyone - it is an open source project created by many people around the world. Different from bitcoin protocol, Ethereum's design is very flexible and adaptable. It is very easy to create new applications on the Ethereum platform. With the release of homestead, anyone can use the applications on this platform safely
Ethereum is a programmable blockchain. It does not give users a series of preset operations, but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator.

2.

At present, there are many channels for domestic users to buy Ethereum. Here are some common channels:

< H2 > 1. Coincola is an over-the-counter trading platform for indivials to trade bitcoin

coy Cola is affiliated to Hong Kong coincola limited, which is developed and operated by a professional international team, focusing on providing convenient and reliable blockchain services for global users. Coincola gathers global users and is committed to building a world-class blockchain asset platform

in coy cola, people from different countries can buy bitcoin with their own currency. The seller of the website publishes the advertisement of selling bitcoin, and explains the payment method and exchange rate. You can choose to trade directly online according to the content of the advertisement. Bitcoin is stored in Ke Ying Cola's Internet wallet. You can transfer bitcoin directly

2. How to buy eth

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register the coincola account, and then click "buy" in the top menu of the home page to enter the advertisement list page

select the appropriate advertisement from the advertisement list and click "buy eth" to enter the transaction page

enter the amount of money to be purchased or the number of digital currency (please understand the message information of the other party, payment method, and transaction instructions of the platform before entering), click buy now, and the order confirmation pop up. After checking and confirming the information, click confirm purchase to enter the order page

in the chat box of the platform, you can inquire whether the other party is online according to the template statement, and make offline payment according to the collection information and collection method provided by the other party

after the completion of offline payment, click the mark that the payment has been completed at the first time (please complete this operation within 15 minutes at the beginning of placing an order, so as to avoid the payment cannot be recovered e to the cancellation of the order e to overtime), and then customize the input information in the chat box to confirm the payment and ask the seller to confirm the collection and release the digital currency

the progress bar in the top column shows that the goods have been received, indicating that the digital currency has arrived in the wallet. Make comments according to the seller's behavior, and click submit to complete the transaction

< / UL > < H2 > 2. C2C trading on trading platform

with the rapid increase in the number of trading platforms and competitive pressure, many trading platforms will have their own C2C trading. Here we take the relatively large ZB trading platform as an example to illustrate

What is C2C

C2C transaction is a customer to customer transaction, which is guaranteed by the transaction platform. There are many such platforms, such as: Fire coin, otcbtc, bitpai OTC, etc., which are guaranteed by the platform and traded between users. We can simply understand it as: our shopping situation on Taobao is the same as that. In case of dispute, the platform will arbitrate. As long as the transaction is carried out according to the normal process, the security of the transaction is guaranteed

2. ZB's C2C business

ZB platform has two choices: QC and usdt. The basic logic is the same. There are many usdt platforms. QC is the feature of ZB, EXX and other platforms. Here we focus on QC

< H2 > about QC

QC is a token. At present, you may know more about usdt and bitcny. At present, there is a special area for QC transaction on ZB. Simply put, QC can buy all other digital currencies (BTC, ETH, EOS, etc.) on ZB. Therefore, after purchasing QC with RMB recharge, you can conct currency transaction on ZB station

The advantage of the < H2 > QC token is that the exchange ratio between the < H2 > < UL >

and RMB is 1:1, which is easier to convert

purchasing other tokens with QC can be directly understood as purchasing RMB, and has an intuitive understanding of the currency price

it takes about half an hour to get to the account. It will take about two hours to get to the account in congestion

ZB platform is relatively reliable, and the reputation of ZB is still very good in the past

How to operate C2C of ZB

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log in to ZB trading platform and click "C2C trading" on the page

to get to the QC transaction page, you need to first bind your bank card. Then, in the buy QC interface, enter the quantity of QC you want to buy. At present, the ratio of QC to RMB is 1:1. Enter the purchase quantity and click "buy now"

after clicking "buy now", you will be prompted to complete the payment within 30 minutes. At the same time, payment information is generated. Please note that the payment must be made according to the prompt

< / UL > < H2 > official statement:

business processing time 9:00-21:00. Non processing time orders will be processed at 9:00 the next day, and the payment will be completed within 24 hours after receiving the order

this means that the merchant you paid will transfer QC coin to your account within 24 hours. According to my experience, you can get to the account in 2 hours ring the day

< H2 > the following points should be paid attention to:

1) make sure to use the newly bound bank card for transfer and payment

2) note information (that 6 digit) must fill in

3) do not use Alipay, WeChat and other transfers. p>

4) do not fill in the opposite account incorrectly

< UL >

about 1-2 hours, you can check whether your QC has arrived in the financial center

after the account is received, you can trade in the "QC" zone of the "spot trading". You can choose the transaction you want to buy and buy the order

3.

what is Ethereum:

Ethereum is an innovation based on the application of technologies and concepts in bitcoin to computers. Ethereum itself imitates a lot of bitcoin technology to maintain the computer platform. Blockchain technology is one of them
Ethereum platform can safely run any program users want

advantages of Ethereum over other competitive currencies before Ethereum appeared, some digital currencies imitated bitcoin. However, these projects have their own shortcomings, they can only support one or several specific applications at the same time< However, the reason why Ethereum can surpass the limitations of these projects in the past is because of the core idea of Ethereum

what Ethereum wants to implement is a blockchain protocol with built-in programming language. Since it supports programming language, in theory, any blockchain application can be defined with this language, and then run on Ethereum's blockchain protocol as an application

The design of Ethereum is very flexible and adaptable

Ethereum target sets the advantages of blockchain technology, in order to add the advantages of blockchain, such as decentralization, openness and security, to almost all computing fields

blockchain applications of Ethereum

Ethereum has many blockchain applications, such as digital applications of gold and stocks, financial derivatives applications, DNS and digital authentication, etc

Ethereum has achieved more than 100 blockchain applications by many start-ups

Ethereum has also been closely watched by some financial institutions, banking consortia (such as R3), as well as large companies like Samsung, Deloitte, RWE and IBM. As a result, a number of blockchain applications such as simplified and automated financial transactions, merchant loyalty index tracking, and gift cards designed to achieve decentralization of electronic transactions have emerged

the relationship between Ethereum and blockchain:

Ethereum is a programmable blockchain

Ethereum does not give users a series of preset operations (such as bitcoin transaction), but allows users to create complex operations according to their own wishes

in this way, Ethereum can be used as a platform for various types of decentralized blockchain applications, including but not limited to cryptocurrency

like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"

4. Ethereum, ETH for short. At the end of 2013, vitalik released the white paper of Ethereum, and in July 2014, the pre-sale of Ethereum began. At that time, insiders called this kind of token issue "crowdfunding". Through the 42 day pre-sale, the Ethereum team raised more than 30000 bitcoins through the pre-sale of 60102216 Ethernet coins; In addition, the early contributors who participated in the development before the pre-sale and the developers who have been engaged in project research for a long time are allocated according to 9.9% of the total amount of Ethernet coins sold at that time. So when Ethereum was officially released, there were more than 72 million Ethereum coins. After the end of Ethereum's pre-sale, it uses the proof of work mechanism POW for mining, and rewards the miners according to 26% of the total amount issued at that time every year. In October 2014, Ethereum reced the block output time from 60 seconds to 12 seconds, and now it is basically stable at 15 seconds, with 5 etheric coins awarded for each block
although the pow mining mechanism is adopted, the block out mechanism of Ethereum is different from that of bitcoin. Due to the short block time of Ethereum, Ethereum is easy to form isolated blocks. Isolated blocks refer to the blocks that are not on the longest chain. Bitcoin's isolated blocks have no block rewards, but in Ethereum, isolated blocks can be referenced. The referenced isolated blocks are called "Uncle blocks", and their packaged data will also be recorded in the blockchain. Unlike bitcoin, Ethereum's TERT block has a reward, and each TERT block can get a reward of 4.375 Ethernet coins at most
Ethereum is a programmable and Turing complete blockchain development platform, which is equivalent to a decentralized global computer. In a programming system, there are usually some virtual machines to compile and execute. Java has JVM. In Ethereum, there is also Ethereum's virtual machine EVM, which can execute any complex algorithm code. Developers can use existing programming languages such as JavaScript or Python to create their own applications on Ethereum. Through Ethereum's virtual machine, you can easily issue digital assets, write smart contracts, set up and run decentralized applications, and set up decentralized autonomous organizations
eth is also known as the internal fuel of Ethereum. Unlike currency digital assets, Ethereum is not only used for transfer, but also for payment of smart contracts
in order to prevent the Ethereum blockchain from being full of junk contracts and junk applications, and to establish and run smart contracts on Ethereum, you must use eth to pay for smart contracts. For example, when you transfer your newly created digital assets on the Ethereum blockchain, you need to use eth to pay the handling fee instead of your newly created digital assets.

5. Go full stack + blockchain course:
a total of 22 weeks, divided into five stages,
the first stage is 4 weeks, go language foundation and network concurrency, learning the introctory go language,
the second stage is 4 weeks, go language practical web development, crawler development, cryptography, consensus algorithm, realizing lightweight public chain, learning the website and crawler that can develop golang, Achieve lightweight blockchain
stage 3, 4-week Ethereum source code analysis and smart contract DAPP development, master Ethereum core and smart contract development, as well as blockchain,
stage 4, 4-week super ledger, bitcoin EOS, source code analysis and smart contract practice, master super ledger development, cat bitcoin, bifurcated EOS after learning, As well as DAPP development of smart contract
phase 5, 6-week project practice, five enterprise level projects, and one year of blockchain project experience after learning
from the characteristics of the language itself, go is a very efficient language, which highly supports concurrency. Go language itself pays more attention to distributed system, and concurrency processing is relatively good, such as advertising and search, That kind of high concurrency server
go language advantages:
excellent performance, can be directly compiled into machine code, does not rely on other libraries, go is extremely fast. Its performance is similar to Java or C + +
concurrency is supported at the language level, which is the biggest feature of go. It is born to support concurrency, and go is the concurrency supported in gene, which can make full use of multi-core and make it easy to use concurrency
the built-in runtime supports garbage collection, which is one of the features of dynamic language. Although GC is not perfect at present, it is enough to cope with most of the situations we can encounter, especially GC after go1.1
it's easy to learn. The authors of go language all have the gene of C, so go naturally has the gene of C. There are 25 go keywords, but the expressive ability is very strong. It almost supports most of the features you've seen in other languages: inheritance, overloading, object, etc
rich standard libraries, go has built a large number of libraries, especially the network library, which is also my favorite part< As like as two peas, br / > built-in powerful tools, Go language is built with many tools chain, the best should be gofmt tools, automatic formatting code, make team review become so simple, code format is exactly the same, it is very difficult to think differently.
cross platform compilation and fast compilation. Compared with the sluggish compilation speed of Java and C + +, the fast compilation time of go is a major efficiency advantage
disadvantages of go language:
package management: package management of go language is absolutely not perfect. By default, it has no way to make a specific version of the dependency library, nor can it create replicable builds. In contrast, python, node and Ruby all have better package management systems. However, with the right tools, the package management of go language can also perform well
lack of development framework: go language does not have a major framework, such as Ruby's rails framework, Python's Django framework or PHP's laravel. This is a heated discussion in the go language community, because many people think that we should not start with using frameworks. This is true in many cases, but if you just want to build a simple crud API, it's much easier to use Django / djrf, rails laravel, or Phoenix
exception handling: go language can help developers deal with compilation errors by simply returning errors (or call stack) through functions and expected calling codes. Although this method is effective, it is easy to lose the scope of the error, so it is difficult to provide meaningful error information to users. Error package can solve this problem by allowing us to add context and stack trace to return error
another problem is that we may forget to handle errors. Static analysis tools such as errcheck and megacheck can avoid these errors. Although these solutions are very effective, they may not be the right way.

6. 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)

7.

1. about the variability of blockchain

2. eth, if most people agree to modify the chain, that is, variability, then they can modify the blockchain records and contracts

3. etc, blockchain records and contracts can't be modified, that is, they can't be tampered with

4. here are the advantages and disadvantages of the two methods

   The advantage of

5. variability is that people can make timely changes to make the right decisions. Therefore, modifying the specification is more practical than finding loopholes

6. non modifiability means that no matter how smart people are at that time, it is impossible not to make mistakes. Therefore, when problems arise in this scheme, it is best to find and solve the loopholes through the existing legal framework

7. differences in development

8. eth, whether it is intentionally arranged or since its birth, the core decisions of blockchain are made by Ethereum foundation with the participation of the community and most of them are developed by it

9. etc, the decision-making of blockchain is mainly decided by the feedback of three loose, collaborative teams with community participation

10. in any case, anyone can put forward improvement suggestions for the two kinds of blockchains. This is the benefit of open source, and it is also very common. You will find that developers of the two chains communicate with each other through GitHub and reddit. I hope to improve the frequency of communication in order to achieve the common goal

11. about compatibility

12. at present, the two kinds of blockchains are compatible with each other. Contracts or applications written by eth can be applied on etc, and vice versa

13. eth, focusing on ewasm, is committed to providing a platform for more and more developers, while the issue of contract security is secondary, such as viper

14. etc focuses on making developers create more secure contracts, such as viper, iohk research, at the cost of consuming the number of potential developers

15. it's obvious that both chains can accept each other, regardless of whether their wishes are the same or not. My view is that the number of developers is not necessarily related to the quality of the proct

16. about the transaction speed

17. eth, the average is 25 seconds, which will be shortened after upgrading

18. etc, with an average time of 14 seconds, maintained at 10-14 seconds after upgrade, according to ecip-1010 and ecip-1036 protocols

19. about the block capacity

20. eth, with the daily trading volume of eth graally reaching 5 million, the block capacity is graally saturated. This situation is similar to the recent transaction cost of bitcoin. This problem can be solved by expanding the block capacity by increasing the default fuel limit

21. ETC­， At present, there is still a lot of room for block capacity. As more and more people accept etc, the block capacity will also increase, just like eth

22. about community

23. eth, mainly discuss on reddit

24. etc, mainly discuss on slack

25. about monetary policy

26. eth, the planned supply is growing steadily, resulting in an average inflation of 3% in eth blockchain in its life cycle

27. etc, before 2025, inflation will reach 3%, and then the total supply will reach 200 million etc, and then there will be deflation

    As for the regional distribution of trading volume, China accounts for 20%, South Korea 25% and the United States 25%
    In etc, China accounts for 50%, South Korea 25% and the United States 10%
    About securities, at present, investors do not have the option to trade securities. Recently, one of eth's ETFs, trading open-end index funds, was denied by the regulators

28. etc owns etc trading trust, which allows investors to own etc instead of the asset itself

8.

Ethereum is an implementation of blockchain. In Ethereum network, many nodes are connected with each other to form Ethereum network:

Ethereum node software provides two core functions: data storage and contract code execution

in each Ethereum node, complete blockchain data is stored. Ethereum not only saves the transaction data on the chain, but also saves the compiled contract code on the chain

At the same time, a virtual machine is provided to execute the contract code

Ethereum virtual machine

Ethereum blockchain not only stores data and code, but also contains a virtual machine (EVM) in each node to execute contract code - it sounds like a computer operating system

in fact, this is the core difference between Ethereum and bitcoin: the existence of virtual machine has brought blockchain into the era of 2.0 and made blockchain a friendly platform for application developers for the first time

the above content comes from the introction course of Ethereum DAPP development

9. Ethereum architecture consciousness is the 6-tier architecture of regional block chain. They are: data layer, network layer, consensus layer, incentive layer, contract layer and application layer. I personally feel that the best thing to do in Ethereum development is Shengshi Huacai, which is very professional

10. Do you understand the difference? The difference is several hundred yuan. Take the money to buy mining machine trusteeship, the effect is better