Ethereum or fabric

1.

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"

2. 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.

3. 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)

4.

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

5. In fact, the rise and fall of digital currency is a normal situation. The key is to see whether you are optimistic about its long-term value. Relatively speaking, if the long-term value is worth investing in, then the short-term decline can be ignored. At the same time, if you don't know much about digital currency users, it is recommended to choose a reliable and good platform for investment. The investment period needs more than six years, Word of mouth should always be good, you can take a look at AEX, fire coin these two, but also more reliable, you can also understand their own network first

6. Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized Ethernet virtual machine to process point-to-point contract through its special cryptocurrency eth. At present, the mining of eth is mainly through the graphics card miner. The so-called graphics card miner is actually similar to the home desktop, but each machine has 6-10 graphics cards and no display

as for the mined mines, the trading platforms can be traded on any platform. The most important thing is to see how you trade. Do you want spot trading or futures trading, because the main procts of each platform are different. If you really can't find a platform, you can try the coinplus platform. It provides a variety of transaction types, and can quickly match orders. It's very convenient to buy and sell. The key is that the service charge is still low.

7. Blockchain learning is more about understanding the idea of decentralization and the value of decentralization. Language is the second thing
however, as Ethereum and hyperledger fabric have the best support for go language, go language must be learned
next, I'll give you the answer to another question, hoping to help you
Background: I started to study blockchain technology in 2015, so I have a certain understanding of blockchain
statement: it is estimated that everyone who sees this question wants to get started with blockchain, so this answer is mainly an introction at the entry level. It's just an introction at the entry level, which is not suitable for blockchain practitioners to improve their learning.

8. Core developer Mike Hearn: why bitcoin should be forked
2015-08-17 09:17:38 Views: key words: Mike

related reading: Mike Hearn: internal contradictions in the enterprise prevent Google from accepting bitcoin

Yes, it's coming. The community is beginning to separate, and bitcoin is about to bifurcate: including software, and perhaps blockchain. The two sides of the split are bitcoin core and the micro variant program based on the same program, called bitcoin XT. On August 16, Beijing time, there is now a full version of bitcoin XT

this bifurcation has never happened before. I want to explain this from the perspective of bitcoin XT developers: it can't be said that it hasn't been communicated enough

bitcoin bifurcation, this topic may make many people curious, so this article is written for ordinary readers. It doesn't involve the knowledge that has been debated before

the original version of bitcoin was carefully arranged by Nakamoto, and has always been very clear. The debate is about growth. In 2008, he answered the first question about the design of bitcoin, saying:

visa processed 37 billion transactions in fiscal year 2008, or an average of 100 million transactions per day. So many deals require 100GB of bandwidth = 12 DVDs or 2 HD quality movies = about $18 of bandwidth at the current price

assuming that the bitcoin network reaches this scale, it will take several years. By then, sending two HD movies over the Internet may not be a big deal

at that time, he was more tired of bitcoin expansion than any of us. His plan is to make bitcoin popular from the beginning, and he knows that this success will change how people use his system. In 2010, he said, "it's good that we keep [blockchain] files as small as possible

the final solution will not care how big it (blockchain file) becomes

but now, while it is still small, keep it in a small state, and the growth of new users will be faster. When I finally implement client only mode, it's no longer a problem
"
in 2011, through a series of calculations, I expanded the expansion intuition of Nakamoto in detail: if bitcoin becomes so popular, will it completely replace visa? The answer is that his plan is credible - you don't need anything else but a computer, even if there's so much traffic. Before he left, I also implemented the model he talked about

it was Nakamoto's plan that brought us together. It has changed the lives of thousands of people around the world. Some of us give up our jobs, others devote their spare time to the project, others set up companies and even travel around the world. This is an idea that ordinary people can complete mutual payment through blockchain and create this global community

that's the vision I signed, and that's the vision Gavin Andresen signed, and that's the vision signed by millions of developers, founders of startups, evangelists, and users around the world

and this vision is now in danger. In recent months, it's clear that a small group of people have completely different plans for bitcoin. These people have never really understood Nakamoto's intention because they are worried about success, if the technology has never been improved, if people can't run bitcoin on their home computers? Doesn't this make bitcoin move away from centralization and more like banking? What if people start to rely on bitcoin, even if it's imperfect

now, Nakamoto has chosen to disappear, and they want to make a major change: substantially increase transaction costs, end support for mobile P2P wallets, give up unconfirmed transactions, and many things that have never been found in the project's founding documents

the so-called lightning network, which is about to be promoted as a substitute for Nakamoto's design, does not exist. The white paper describes that it was announced earlier this year, and if it can be realized, it will be a huge departure from the bitcoin we know and love. Pick one of the many differences, and a bitcoin address won't work. What they will be replaced with has not yet been worked out (because no one knows). There are many other surprising pitfalls that I mentioned in another article. What will it eventually proce to make our existing bitcoin network better? It is still extremely unclear

what happened to the free market

in theory, none of this should be a problem. Lightning network is built on the blockchain, but it needs a rather trivial upgrade process to achieve the best function. Of course, people are willing to explore this direction, which is entirely possible. If the jobs they set up are better than the existing ordinary bitcoin network, then the market will choose their way, if so... It is fair competition for them! The current design of bitcoin is unlikely to be the final version for payment. This is a reasonable imagination, one day it will be eliminated in the competition, or enhanced by something else

but our system is working today. It has an ecosystem, including developers, exchanges, wallets, ATMs, books, applications, conferences, and many people have learned how it works

if there was a free choice, would people decide to move to a completely different system

we don't know, but the people who are pushing these things don't want the market to make a decision. That's what happened

a long time ago, Nakamoto set up a temporary "mixed brand assembly computer": he limited the size of each block to 1 MB. He did so in order to keep the blockchain in a small state in the early days, until we now call it the creation of SPV wallet (that is, what Nakamoto calls "client only mode"). As mentioned above, when the time comes, it can be adjusted. It has never been said that it is permanent. In the end, it becomes irrelevant. In 2011, I wrote the first SPV tool with my respected colleague Andreas schildbach, and we built the first and most popular Android wallet together. Since then, SPV wallets have been used on major platforms. Therefore, Nakamoto's reasons for this temporary restriction have been solved a long time ago

with the continuous growth of bitcoin, its blocks are also growing. Reasonable traffic forecasts show that the block will reach the current system limit sometime next year, at the latest in 2017. Another bubble or pressure cycle will force us to exceed that limit before, and the result may not be beautiful.

so it's time to raise the upper limit, or delete it completely. That's our plan, and the problem starts: those who don't want to see bitcoin expand have decided to postpone the process. They saw a beautiful, one-time opportunity to forcibly transfer bitcoin's predetermined path to a completely different technological trajectory. They don't know what this alternative design will be, and of course they haven't built it yet. But it doesn't matter. They believe that by blocking the growth of the blockchain, they can "motivate" (that is, force) the bitcoin community to switch to different things, something more in line with their personal technical taste

why restrict blockchain

so far, I haven't explained much about these people or who they are. I think it's a very time-consuming and laborious thing to name names in this article, and it seems to be futile in the end. Presumably those who care about this matter already know it, and those who don't know it can't recognize the people who are involved in it

I just want to say that they are very few people who have access to the bitcoin core code base, or those who are convinced by their arguments

therefore, we will not discuss these arguments here, which has been too much. Gavin and I have written articles to analyze the questions raised by everyone to refute them. Sometimes the answer is some common sense, some will be more in-depth, need more work, such as network simulation

the best place to understand these controversies is in Gavin's blog. I hope to find a link to a collection of opinions similar to those refuting Gavin's point of view, but none of them

to sum up, in the long and hard debate, several different opposition groups:

if bitcoin approaches this limit, we will be stimulated to create something better
the limit should be raised, but it is not ready (the actual time is not specified)
if bitcoin is expanded and becomes more centralized, it will no longer be bitcoin< Other people: if the objections you support are not listed above, please check Gavin's blog and find out the answer

the first point may become a reality one day, but it is not comparable with the theoretical system on paper. But no one who has seen any alternative solutions on the table thinks they can be implemented within 12 months (see another example in the last paragraph, for example)... Even assuming they are better. This is also an example of the nirvana fallacy:

the nirvana fallacy refers to the name of the informal fallacy of some unrealistic and idealized substitutes for something more practical. It can also refer to the tendency to think that there is a perfect solution to a specific problem, so it is also called perfectionism fallacy
it's obviously advantageous to create an imitative dichotomy for a current choice. But it's also totally incredible. One who uses the nirvana fallacy can attack any opposing idea because it is imperfect. According to this fallacy, the choice is not between real-world solutions. One is a realistic solution, and the other is an impractical solution, which is the "better" choice between the two

the answer to the second objection is too vague. It is reasonable to believe that the overall upgrade of each bitcoin node may take one year, and the actual bitcoin network capacity overload will cause serious damage. We really should be ready before that. In the bitcoin development mailing list, there are two people who have professional capacity planning experience, and both of them have

9.

Bitcoin is actually a string of data in the bitcoin network. Where should this data be stored? Just as our bank cards and cash can be stored in our wallets, bitcoin also has its special wallet, which is bitcoin wallet. In fact, bitcoin wallet does not contain bitcoin. Bitcoin wallet is a database composed of private key and public key. Bitcoin itself is stored in the blockchain. Users sign the transaction with their private key to prove that they have the transaction. Blockchain is a huge database ledger, so this transaction will remain in the blockchain database, and no one can tamper with it

with & lt; Multi signature & quot; With the application of multi signature technology in the field of wallet, a multi signature wallet emerges as the times require& ldquo; Multi signature & quot; What do you mean? Usually, a private key corresponds to a bitcoin address, and the assets on the address of bitcoin can be transferred with this private key. The process of encrypting with private key is signature. Multi signature means that before an address uses bitcoin, it needs multiple private keys to sign

in other words, a transaction needs two to three or more private key signatures to process bitcoin in the address. In this way, the security of our assets is greatly improved, and it is also applicable to the bitcoin transfer of institutions, without affecting its speed. Generally speaking, a light purse is enough for beginners, and it is convenient and easy to use. But we must pay attention to the security problem and keep the private key well

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