Bitcoin blockchain head

1. Forking is different from ordinary upgrading. Ordinary upgrading does not affect agreement consensus before and after upgrading, and generally does not need the participation of community consensus or computing consensus. According to the modification of the protocol, bifurcation can be divided into soft bifurcation and hard bifurcation

existing definition:

[lightning definition] hard fork refers to that when the bitcoin block format or transaction format (this is the widely spread "consensus" (should be part of the agreement consensus)) changes, the UN upgraded node refuses to verify the blocks proced by the upgraded node, but the upgraded node can verify the blocks proced by the UN upgraded node, Then we continue the chain that we think is right, so we divide it into two chains< A permanent divergence in the block chain, commonly occurs when non upgraded nodes can't validate blocks created by upgraded nodes that follow new consensus rules, The UN upgraded node can verify the blocks proced by the upgraded node, and the upgraded node can also verify the blocks proced by the UN upgraded node<

a temporary fork in the block chain which commonly occurs when miners using non upgraded nodes vialate a new consensus rule their nodes don't know about.

I don't think we can say which definition is right or wrong. The specific definition can be summed up according to the differences between the two that have been widely agreed in the community, and it doesn't need authority to specify

hard fork: without forward compatibility, the previous version will be unusable and need to be upgraded

soft fork: it has good compatibility, at least some functions of previous versions are available, and can not be upgraded

hard branching: at the level of blockchain, there will be two branching chains, one old chain and one new chain

soft bifurcation: there are no forked chains at the level of blockchain, but only the blocks that make up the chain, including new blocks and old blocks

hard forking: it is necessary to agree with the forking upgrade at a certain time point, and those who do not agree will enter the old chain

soft bifurcation: for quite a long time, it is allowed to continue to use the original version to generate old blocks and coexist with new blocks without upgrading

2. Bitcoin is a kind of virtual digital currency proposed by Nakamoto in 2009. It is characterized by no centralized issuing institution and a fixed total of 21 million pieces. It is not a one-time issue and needs to be proced by miners. Due to the decentralized structure, trust needs to rely on cryptography and consensus mechanism technology to achieve
blockchain is a general technology derived from bitcoin. It implements a decentralized database model. Bitcoin can be called blockchain 1.0 because it has no concept of smart contract. The key technologies of blockchain include cryptography encryption and decryption and consensus mechanism. Blockchain is generally used to combine with specific business logic, which needs to rely on smart contract, which provides an execution mode free from human interference
the IPO of ICO originates from the concept of initial public offering (IPO) in the stock market. It is the behavior of blockchain project to issue token for the first time, raise bitcoin and solve Ethereum and other common digital currencies.

3. Blockchain is technology, bitcoin is digital currency or electronic currency based on blockchain technology, and blockchain technology is the basic technology of all digital currencies. The two are complementary. ICO is the first time to issue currency, which is similar to IPO in stocks

4. Bitcoin blockchain is a bitcoin blockchain? No, the block stores the transaction. In the early stage, you will get a coin if you successfully build a block. In the later stage, you can only get the fees paid by the exchange. A currency is a string of digital signatures. It is a digital signature sent by the last owner to the receiver. Everyone can see who owns the currency from the transaction
does each node have complete blockchain data? You mean a user node? A user node needs to keep the of the block head of the longest workload proof chain, so it knows the data of all the block heads. It can move forward to know all the data on the block chain, but not all of them are saved. A block header is very small, only 80 bytes, which can be saved completely, because the generation of nodes is very slow. Even with the passage of time, the amount is not too large now.

5. With the advent of bitcoin, a new technology, blockchain, has come into the public view. What is the relationship between bitcoin and blockchain? The simplest understanding is: blockchain is the underlying technology of bitcoin, and bitcoin is the first generation application of blockchain. Therefore, we often see such a saying that "bitcoin represents the era of blockchain 1.0"

bitcoin is regarded as the first generation application of blockchain technology and the most thorough application of its code testing. However, without bitcoin, there might not be so many people who knew about blockchain now. It can be said that bitcoin has greatly improved the "exposure" of blockchain technology

later, people graally found that the application value of blockchain is far more than bitcoin, but can be applied to many instries to solve the pain points of many instries; The idea of blockchain can also provide a lot of reference for the financial field, which is the real reason for the outbreak of blockchain.

6. Sintering machine is actually a sintering system, including civil engineering, which transports materials from the manufacturer. The ring sintering machine is suitable for small blast furnaces. Dingxin of Shanye and Dingxin of Shanxi are good domestic ones. They have blast furnace operation experience and can achieve good economic indicators. After all, the purpose of opening the plant is to make money.

7. Method 1: enter DFU mode when power on
connect the device to the computer with USB cable, and then you will hear the prompt sound that the computer has been connected successfully
please turn off the device first, and then you will hear the prompt that the computer is not connected successfully
first press and hold the power key to display the apple logo, and then press and hold the on / off key and the home key until the logo disappears. Continue to press and hold the power key for about 4-5 seconds, and continue to press and hold the home key until an iPhone in recovery mode is detected by iTunes (if successful, the iPhone should be in black screen). If redsn0w is used to detect, the device model in DFU will be displayed at the bottom of the interface< Method 2: enter DFU in any state (white apple or unlimited restart)
connect the device to the computer
Press and hold the on / off key and home key directly until the logo disappears. Just follow the above steps
method 3: do not press the key to enter the DFU (it is recommended to use the device with damaged key)
download the firmware of the device corresponding to the latest system version (do not use the firmware that Apple has closed for verification)
Download redsn0w and enter extra even more DFU IPSW in turn
at this time, redsn0w will prompt you that this is the operation of making DFU firmware, not the normal operation of restoring the system. The choice is
after selecting the latest official firmware, redsn0w will start making DFU firmware and wait for completion
Open iTunes, close redsn0w, shift + restore (for Mac, please use option + restore) and select the DFU firmware (prefixed with enter)_ DFU), wait for error 37 in the recovery process. At this time, the device is already in DFU mode.

8. Bitcoin market can now be seen on professional software, such as the coin card I use now. I think it's very good. Most of the data are available and updated in a timely manner. I recommend you to download and use it