How much is the Ethereum interface
each version of Ethernet has a maximum cable length limit (that is, the length without amplification). Signals within this range can propagate normally, and signals beyond this range cannot propagate
in order to allow the construction of a larger network, repeaters can be used to connect multiple cables. Repeater is a physical layer device, which can receive, amplify and retransmit signals in two directions
extended data
several common Ethernet interface types
1. SC optical fiber interface
SC optical fiber interface has been applied in the era of 100base TX Ethernet, so it was called 100base FX at that time (F is the abbreviation of optical fiber). However, at that time, because the performance was not more prominent than twisted pair, but the cost was higher, so it was not popularized. Now the instry vigorously promotes gigabit network, and SC optical fiber interface is re valued
2. RJ-45 interface
this kind of interface is the most common network equipment interface, commonly known as "crystal head", and the professional term is RJ-45 connector, which belongs to the type of twisted pair Ethernet interface. RJ-45 plug can only be inserted along the fixed direction, and a plastic spring piece is set to be stuck with RJ-45 slot to prevent it from falling off
3. FDDI interface
FDDI has the highest transmission rate among the mature LAN technologies. It has the characteristics of timed token protocol, supports a variety of topologies, and its transmission medium is optical fiber. Fiber distributed data interface (FDDI) is a set of protocols developed by American National Organization for Standardization (ANSI) to transmit digital signals on optical cables
reference source: Network Ethernet interface
If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records
the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:
< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});
Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query
recommend a practical introction, you can see: Ethereum tutorial
1. First, we click Start - control panel
Generally speaking, the steps of deploying smart contract are as follows:
- start an Ethereum node (such as geth or testrpc)
- use Solc to compile smart contracts=& gt; Get the binary code
- deploy the compiled contract to the network This step will consume Ethernet currency, and you need to use the default address or specified address of your node to sign the contract.)=& gt; Get the blockchain address and ABI of the contract (JSON representation of the contract interface, including variables, events and callable methods) The author confused ABI with contract interface here. ABI is the binary representation of the contract interface.)
- use the JavaScript API provided by web3.js to call the contract Depending on the type of call, it may consume Ethernet currency.)
After reading the answers of other respondents, I really want to laugh. It's not terrible to pretend that I don't understand. What's terrible is to answer blindly. There's something wrong with this question. The burst of 5.7 billion yuan has nothing to do with a drop of 10 cents. It can even be said that its disappearance is e to the sharp rise. So where is the decline? If bitcoin really falls, it will not be 5.7 billion capital washed away, it will be tens of billions, hundreds of billions of capital evaporated, those who talk about trends and development, please study the capital and stock market well, and by the way, please search for the meaning of the word "burst", no culture is too terrible
in addition, I would like to make a digression. Recently, a hot topic is fund. In 2021, the annual meeting is more or less a national fund. In 2020, the fund manager is still a good active fund. Even if the position is not changed, the annual yield will reach at least 40%, but this does not mean that this year is still OK, It's not that everyone can make money playing with funds. it's similar to the nature of stocks. Index funds, stock funds and even active funds are risky. I think many people say that they should get on the bus quickly. They are really worried about your funds of course, 2021 may be a bull market. It is estimated that the whole network has spread, many people are rubbing their hands to make a lot of money, but I can't do much. I just advise you not to go with the flow too much, don't be greedy, and don't think you are. That's all. Good luck
Recently, a & lt; The 27 year old founder of ether coin made a profit of US $1.1 billion; The news of, caused the hot discussion of broad netizens, make boiling on the net. We know that with the development of society, the level of science and technology is becoming more and more developed. In recent years, digital currency is very popular. More than ten years ago, a bitcoin was less than one cent, but now it needs more than 300000 RMB to buy one. Because of the rise of bitcoin, people realize the charm of digital currency, so they are attacking digital currency one after another. They have developed many different kinds of digital currency, such as ether coin, dog coin and so on. Recently, it is reported that the founder of 27 year old ether coin has made a profit of $1.1 billion. So can etheric currency still be g? Let's find out
First of all, the answer is yes. Now we can still dig ether coins{ RRRRR}the above are my views on this issue. They are purely personal views and are for reference only. If you have any different views, you can leave a message in the comment area for discussion
the first category is familiar game currency. In the era of stand-alone games, the protagonist accumulates money by knocking down the enemy, entering the gambling house to win money, and using these to buy Herbs and equipment, but it can only be used in his own game console. At that time, there was no "market" between players. Since the establishment of Internet portal and community, the realization of game networking, virtual currency has a "financial market", players can trade game currency
the second type is the special currency issued by the portal website or instant messaging service provider, which is used to purchase the services in the website. The most widely used is Tencent's q-coin, which can be used to purchase membership, QQ show and other value-added services
the third kind of virtual currency on the Internet, such as Fuyuan currency (FTC), bitcoin (BTC), Wright currency (LTC), etc. bitcoin is an electronic currency proced by open-source P2P software. Some people also translate bitcoin as "bitcoin", which is a kind of network virtual currency. It is mainly used for Internet financial investment, and can also be directly used in daily life as a new currency.