Content structure diagram of blockchain
From the perspective of technology and architecture, I will tell you my understanding of blockchain in common language
what is blockchain? In a word, blockchain is a storage system. To be more specific, blockchain is a distributed storage system without an administrator and each node has all the data
What are the common storage systems like
first, how to ensure high availability
the common storage system usually uses "rendancy" to solve the problem of high availability. As shown in the figure above, if the data can be copied into several copies and rendant to multiple places, high availability can be guaranteed. The data in one place is hung, and there is data in other places. For example, the master-slave cluster of MySQL is the same principle, and the raid of disk is also the same principle
two points need to be emphasized in this place are: data rendancy often leads to consistency problems
1. For example, in the master-slave cluster of MySQL, there is actually a delay in reading and writing, which means there is a inconsistency in reading and writing in a short period of time. This is a side effect of data rendancy
The second point is that data rendancy often reces the efficiency of writing, because data synchronization also consumes resources. If you add two slave libraries, the write efficiency will be affected. The common storage system is to use rendancy to ensure the high availability of dataso the second question, ordinary storage system, can write more
the answer is yes, for example, take this graph as an example:
in fact, MySQL can do a master-slave synchronization of al masters, master-slave synchronization of al masters, two nodes can be written at the same time. If you want to do a multi room multi live data center, in fact, multi room multi live data synchronization. What we should emphasize here is that multi-point writing often leads to the consistency problem of writing conflicts. Take MySQL as an example, suppose that the attribute of a table is self incrementing ID, then the data in the database is 1234 now. If one of the nodes writes and inserts a piece of data, it may become 5, and then these 5 pieces of data are synchronized to another master node, Before synchronization, if another write node inserts a piece of data, a piece of data with self incrementing ID of 5 will be generated. Then, after the generation, synchronize to another node, and the synchronized data will conflict with the two local 5's after it arrives, which will lead to synchronization failure and write consistency conflict. This problem will occur in the case of multi-point writing
how to ensure consistency in multi-point writing
the reform "Swan class" gives you more technical work
Seeing some answers to the debate on the definition of blockchain, I suddenly realize that my answer to this explanation principle has always been directed at bitcoin. There is no specific and unique answer in the instry between the definition of blockchain. Here I first summarize the characteristics of "blockchain" according to the papers I read:
1; Hash chain & quot There are several nodes participating in the system operation (distributed)
3. Reach a consensus on the consistency of basic data (consensus agreement / algorithm) through a certain protocol or algorithm
since bitcoin is currently one of the most typical and influential applications of blockchain, it will be much easier to understand how bitcoin uses blockchain before understanding other forms of blockchain applications
2-The distributed database is the physical carrier of the blockchain, and the blockchain is the logical carrier of the transaction. All core nodes should contain the full of the blockchain data
3-The blockchain serializes the blocks according to time, and the blockchain is the only body of the whole network transaction data
4-The blockchain is only effective for adding, Invalid for other operations
5-public-private key verification based on asymmetric encryption
6-accounting node requires that Byzantine general problem can be solved / avoided
7-consensus progress is evolutionarily stable, that is, it will not collapse in the face of a certain amount of contradictory data of different nodes
8-consensus process can solve the problem of double spending
five characteristics of blockchain:
decentralized
e to the use of Distributed Accounting and storage, there is no centralized hardware or management organization, the rights and obligations of any node are equal, and the data blocks in the system are jointly maintained by the nodes with maintenance function in the whole system
thanks to the decentralization of blockchain, bitcoin also has the characteristics of decentralization [6]
openness
the system is open, in addition to the private information of all parties to the transaction is encrypted, the data of the blockchain is open to all, and anyone can query the blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
autonomy
blockchain adopts consensus based specifications and Protocols (such as a set of open and transparent algorithms) to enable all nodes in the whole system to exchange data freely and safely in a de trusted environment, so that the trust in "people" is changed into the trust in machines, and any human intervention does not work
information cannot be tampered with
once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% of the nodes in the system can be controlled at the same time, the modification of the database on a single node is invalid, so the data stability and reliability of the blockchain are extremely high<
anonymity
since the exchange between nodes follows a fixed algorithm, their data interaction does not need trust (the program rules in the blockchain will judge whether the activity is effective by themselves), so the counterparties do not need to let the counterparties generate their own trust by disclosing their identities, which is very helpful for credit accumulation.
What kind of blockchain technology is popular recently? Blockchain technology is considered to be the brightest star in financial technology, and it may continue to develop in the future. It has many characteristics, including data distribution, data trust and collective consensus mechanism, and most importantly, openness, transparency, anonymity and privacy, According to the data in the blockchain, we can get some basic information of contemporary society
blockchain technology is such a safe and scientific database. It can be simply understood as an authoritative database, in which the basic content is true, verified and audited by others. In terms of financial technology, it is very easy to find some desired data, which is very good for business people
1, data layer / data layer
the data layer mainly describes the physical form of blockchain, which is a chain structure starting from Genesis block on blockchain, including block data, chain structure, random number, time stamp, public and private key data on blockchain, and is the lowest level data structure in the whole blockchain technology
2. Network layer / network layer
the network layer mainly realizes the mechanism of distributed network through P2P technology, and the network layer includes P2P networking mechanism, data dissemination mechanism and data verification mechanism. Therefore, blockchain is essentially a P2P network with automatic networking mechanism, and the communication between nodes is maintained by maintaining a common blockchain structure
3. Consensus layer / consensus layer
consensus layer mainly includes consensus algorithm and consensus mechanism, which enables highly dispersed nodes to reach consensus on the effectiveness of block data efficiently in the decentralized blockchain network. It is one of the core technologies of blockchain and also the governance mechanism of blockchain community. At present, there are at least dozens of consensus mechanism algorithms, including workload proof, rights and interests proof, rights and interests authorization proof, burning proof, importance proof and so on
data layer, network layer and consensus layer are the necessary elements of building blockchain technology. Without any layer, it can not be called a real blockchain technology
4. Incentive layer / activator layer
the incentive layer mainly includes the issuing system and distribution system of economic incentive. Its function is to provide certain incentive measures, encourage nodes to participate in the security verification work in the blockchain, incorporate economic factors into the blockchain technology system, encourage nodes that comply with rules to participate in bookkeeping, and punish nodes that do not comply with rules
5. Contract layer / contract layer
the contract layer mainly includes various scripts, codes, algorithm mechanisms and smart contracts, which is the basis of block chain programming. Embedding the code into the blockchain or token, realizing the smart contract that can be customized, and automatically executing without a third party when certain constraints are met, is the foundation of the blockchain's distrust
6. Application layer / application layer
the application layer of blockchain encapsulates various application scenarios and cases, which are similar to applications on computer operating system, portals on Internet browsers, search engines, e-malls or apps on mobile phones. The blockchain technology applications are deployed on Ethereum, EOS and qtum, and are implemented in real life scenarios. The future programmable finance and programmable society will also be built on the application layer
incentive layer, contract layer and application layer are not necessary factors for each blockchain application, and some blockchain applications do not completely include the three-tier structure.
to practice guitar: most of them are basswood panels, some even basswood back panels, which are less than 300 yuan, also known as firesticks (because they are made of the same material as firewood, and the intonation is poor)
entry guitar: most of them are spruce panels, rosewood finger boards, and the back panels are not necessarily. The price is about 1000 yuan, and most of them are 500 yuan or 600 yuan, About 1000 yuan, there are also some elementary Miandan Qin
medium Guitar: most of them are spruce panel, rosewood fingerboard, back side panel, mahogany and fire rosewood. Generally, they are middle end single piano of various series, and some of them are full single (very few), with the price around 3000
high end: all single guitars and spruce veneers are the most popular. The price is four or five thousand or more. There is no upper limit. There are tens of thousands of them, but most people don't need them
tips on guitar selection: http://www.jitatang.com/guitar It is recommended to refer to
no matter where you buy it, you should know some experience to avoid being trapped. Generally, you will be trapped when you go to a piano shop for the first time. The most important two points (you can't hear the timbre and so on):
1. Look at the appearance and choose the log color or black directly Sunset color (the classic three color system), never white, Pink Guitar, that is the above said practice piano grade
2. Check the handle. When the guitar is tuned to the standard pitch, the distance between the string and the fingerboard should be about 3mm (that is, the thickness of a coin) at the 12th point. If you press the string too high, you will feel tired, otherwise it will cause the phenomenon of playing. A good hand feeling is that you can easily press any tone with your left finger without any proct or noise, and you don't feel any effort when you press it horizontally
3. Performance (in fact, you can't see it. You can get what you pay for. It's right to choose the most expensive one in your budget.)
protocol layer
the so-called protocol layer refers to the lowest level technology. This level is usually a complete blockchain proct, similar to the operating system of our computer. It maintains network nodes and only provides API for calling. Usually, the government will provide a simple client (commonly known as wallet). The function of this client wallet is also very simple. It can only establish address, verify signature, transfer payment, check balance, etc
extension layer
this layer is similar to the computer driver, which is to make blockchain procts more practical
application layer
this layer is similar to all kinds of software programs in computers. It is a proct that ordinary people can really use directly, and it can also be understood as the browser of B / S architecture procts. The application of this level is almost blank at present.
1. Data layer: encapsulates the underlying data block and related data encryption and timestamp technologies
2. Network layer: includes distributed networking mechanism, data propagation mechanism and data verification mechanism
3. Consensus layer: it mainly encapsulates various consensus algorithms of network nodes; The incentive layer integrates economic factors into the blockchain technology system, mainly including the issuance mechanism and distribution mechanism of economic incentives
4. Contract layer: it mainly encapsulates all kinds of scripts, algorithms and smart contracts, which is the basis of the programmable characteristics of blockchain; At present, jinwowo in Southwest China has taken the lead in big data research with blockchain as the underlying technology, and also provides big data services with blockchain as the underlying technology
5. Application layer: encapsulates various application scenarios and cases of blockchain. In this model, chain block structure based on timestamp, consensus mechanism of distributed nodes, economic incentive based on consensus computing power and flexible and programmable smart contract are the most representative innovations of blockchain technology