Ethereum node synchronization

1. A virtual currency with a wallet doesn't mean it's more professional and advanced. The existence of digital currency wallet is the premise of currency existence. Currency without wallet can be identified as fraud
mainstream digital currencies such as bitcoin, Puyin, Laite, Ethereum and dogcoin all exist in wallets, and wallets existed before the release of such currencies.

2. 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)

3.

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

4. The network will be upgraded to Constantinople & Petersburg at block height of 7280000. L, Z, b show that it will be upgraded on March 1, 2019 Beijing time. I don't know if the upgrade is successful

5. Yes, but it is better to use overseas servers. In addition, the server configuration should be medium or above.

6. Generally speaking, undefined index is the exact writing problem in the process of writing. Notice generally prompts for errors that are not directly related to the execution of code, but don't forget that notice sometimes returns some rendant error information

7. How many account addresses can an Ethereum node have at most
A: generally, there is only one account address, otherwise there will be an error! Blockchain itself is unique. If there are multiple account addresses on one node, it violates the fundamental principle of blockchain!

8. There is no problem at all, but relatively speaking, we must buy some reliable ones, because we must pay attention to them.

9. Return the result of ifconfig
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address