Is it useful to learn blockchain
What is the prospect of blockchain technology? The following is just personal experience and opinions, for reference and learning only
I have been in touch with the blockchain instry for many years, and I have my own views and understanding from its ups and downs. I personally think blockchain technology is still very good. The reasons are as follows:
first, blockchain technology as a rookie after the Internet, the Internet is the transmission of information, and blockchain is the exchange of value. The development trend of blockchain is similar to that of Internet
2. After the blockchain has gone through great waves and been widely misunderstood, there are still many blockchain explorers and practitioners in the instry making continuous efforts
Third, with the attention of the country and other countries to the blockchain instry, governments all over the country have set up blockchain development funds to promote the development of the local blockchain instry, so as to occupy the highland of the blockchain instry Fourthly, the Internet of things is the development trend in the future. In the face of the growing demand of the Internet of things ecosystem, the computing power of the central server is severely challenged, and decentralization becomes the key to solve this problemthe above content is only a new point of view, or it needs specific analysis of specific issues. After all, practice is the only standard to test the truth
blockchain is a term in the field of information technology. In essence, it is a shared database. The data or information stored in it is characterized by "unforgeability", "trace in the whole process", "traceability", "openness and transparency" and "collective maintenance". Based on these characteristics, blockchain technology has laid a solid "trust" foundation, created a reliable "cooperation" mechanism, and has broad application prospects
characteristics of blockchain technology
decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
security. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
Mining
krypton gold mine
medicine mining
more
nightmares rattan
Taylor
anything
is good
but now WLK does not open
FB
is rolling
so the demand for medicine is relatively small
recommended map: ordham goes around the top half of the mountain, and twilight heights digs around the river from the harbor. And deep rock abyss.. Forget) this map has two ore circles, the inner circle and the outer circle. There's almost no iron burning on this map. It's all black and white. If no one digs, the profit is not as good as the first two. If there are too many people, you can go here to dig. If there are few people, the place is big.
the price of low-grade ores is different on each server. You have to watch ah often. Silver mine must be expensive, but it's usually not found, so you don't need to dig it. Silver is certainly the least valuable, but it is accompanied by arcane crystal. One can sell about 100g, mainly distributed in hilisus, crater and winter spring valley. It depends on market demand. For example, when do magic or orange hammer suddenly more, black iron will greatly increase the price. Watch carefully
pure hand fight, hope to adopt, thank you
the main protocols are as follows: 1. IP internet protocol IP is the heart of TCP / IP and the most important protocol in the network layer. The IP layer receives the data packet from the lower layer (network interface layer, such as Ethernet device driver) and sends the data packet to the higher layer -- TCP or UDP layer; On the contrary, IP layer also transfers packets received from TCP or UDP layer to lower layer. IP packets are unreliable because IP doesn't do anything to confirm that the packets are sent in order or are not corrupted. IP packet contains the address of the host sending it (source address) and the address of the host receiving it (destination address). When high-level TCP and UDP services receive packets, they usually assume that the source address in the packet is valid. It can also be said that IP addresses form the authentication basis of many services, which believe that packets are sent from a valid host. IP confirmation contains an option called IP source routing, which can be used to specify a direct path between the source address and the destination address. For some TCP and UDP services, IP packets using this option seem to be delivered from the last system on the path rather than from its real location. This option exists for testing purposes, indicating that it can be used to spoof the system to make normally forbidden connections. Then, many services that rely on IP source address for confirmation will have problems and will be illegally intruded. 2. TCP if there are already sealed TCP packets in IP packets, then IP will "up" them to the TCP layer. TCP sorts packets and checks for errors, and realizes the connection between virtual circuits. TCP packets include sequence number and acknowledgement, so packets not received in order can be sorted, while damaged packets can be retransmitted. TCP sends its information to higher-level applications, such as telnet's server and client. Applications send information back to the TCP layer in turn, and the TCP layer sends them down to the IP layer, device drivers and physical media, and finally to the receiver. Connection oriented services such as Telnet, FTP, rlogin, X windows, and SMTP require a high degree of reliability, so they use TCP. DNS uses TCP (send and receive domain name databases) in some cases, but uses UDP to send information about a single host. 3. UDP is in the same layer as TCP, but it doesn't care about the order, error or retransmission of packets. Therefore, UDP is not used for connection oriented services that use virtual circuits. UDP is mainly used for query response oriented services, such as NFS. Compared with FTP or Telnet, these services need to exchange less information. Services that use UDP include NTP (Network Time Protocol) and DNS (DNS also uses TCP). Spoofing UDP packets is easier than spoofing TCP packets because UDP does not establish an initial connection (also known as handshake) (because there is no virtual circuit between the two systems), that is, UDP related services are at greater risk. 4. ICMP ICMP is located in the same layer as IP, which is used to transmit IP control information. It is mainly used to provide information about the path to the destination address. ICMP's "redirect" information informs the host of a more accurate path to other systems, while the "unreachable" information indicates that there is a problem with the path. In addition, if the path is not available, ICMP can terminate the TCP connection "gracefully". Ping is the most commonly used ICMP based service. 5. Port structure of TCP and UDP TCP and UDP services usually have a client / server relationship. For example, a telnet service process starts to be idle on the system, waiting for connection. The user uses the telnet client to establish a connection with the service process. The client program writes information to the service process, the service process reads the information and sends a response, and the client program reads the response and reports it to the user. Therefore, the connection is plex and can be used for reading and writing. How do multiple telnet connections between two systems confirm and coordinate with each other? A TCP or UDP connection uniquely uses the following four items in each message: the source IP address, the IP address of the sending packet. Destination IP address the IP address of the received packet. Source port the port of the connection on the source system. Destination port the port of the connection on the destination system. Port is a software structure, which is used by client program or service process to send and receive information. A port corresponds to a 16 bit number. Service process usually uses a fixed port, for example, SMTP uses 25, xwindows uses 6000. These port numbers are "well known" because these addresses and destination addresses are needed to communicate when establishing a connection to a particular host or service
reference model
TCP / IP protocol does not fully conform to OSI's seven layer reference model. The traditional open system interconnection reference model is a seven layer abstract reference model of communication protocol, in which each layer performs a specific task. The purpose of this model is to make all kinds of hardware communicate with each other at the same level. These seven layers are: physical layer, data link layer, network layer, transport layer, session layer, presentation layer and application layer. The TCP / IP communication protocol adopts a four layer hierarchical structure, and each layer calls the network provided by its next layer to fulfill its own requirements. These four layers are: application layer: the layer of communication between applications, such as simple e-mail transfer (SMTP), file transfer protocol (FTP), network remote access protocol (telnet), etc. Transport layer: in this layer, it provides data transmission services between nodes, such as transmission control protocol (TCP), user datagram protocol (UDP), etc. TCP and UDP add transmission data to the packet and transmit it to the next layer. This layer is responsible for transmitting data and determining that the data has been delivered and received. Interconnection network layer: it is responsible for providing basic packet transmission function, so that each packet can reach the destination host (but not check whether it is received correctly), such as Internet Protocol (IP). Network interface layer: manage the actual network media, define how to use the actual network (such as Ethernet, serial line, etc.) to transmit data
the reason why TCP / IP is a protocol family is that TCP / IP protocol includes TCP, IP, UDP, ICMP, rip, telnet FTP, SMTP, ARP, TFTP and many other protocols, which are collectively called TCP / IP protocol. Here we introce the English names and uses of some common protocols in the protocol family: TCP (Transport Control Protocol), IP (Internet Protocol), UDP (User Datagram Protocol), ICMP (Internet control message protocol) and SMTP (Simple Mail Transfer Protocol) Protocol SNMP (Simple Network Management Protocol) FTP (File Transfer Protocol) ARP (address resolution protocol) address resolution protocol from the perspective of protocol layered model, TCP / IP consists of four layers: network interface layer, inter network layer, transport layer and application layer. Among them: network interface layer, which is the lowest layer of TCP / IP software, is responsible for receiving IP datagrams and sending them through the network, or receiving physical frames from the network, extracting IP datagrams and giving them to the IP layer. The inter network layer is responsible for the communication between adjacent computers. Its functions include three aspects. 1、 After receiving the request, the packet is loaded into the IP datagram, the header is filled, the path to the destination machine is selected, and then the datagram is sent to the appropriate network interface. 2、 Processing input datagram: first check its validity, and then carry out pathfinding - if the datagram has arrived at the sink machine, remove the header and hand over the rest to the appropriate transport protocol; If the datagram has not arrived at the sink, the datagram is forwarded. 3、 Deal with path, flow control, congestion and other issues. The transport layer provides communication between applications. Its functions include: 1. Format information flow; 2、 Provide reliable transmission. In order to realize the latter, the transport layer protocol stipulates that the receiver must send back an acknowledgement, and if the packet is lost, it must be retransmitted. The application layer provides users with a set of common applications, such as e-mail, file transfer access, remote login and so on. Telnet uses telnet protocol to provide interfaces registered on other hosts in the network. Telnet session provides character based virtual terminal. File transfer access FTP uses FTP protocol to provide file function between machines in the network. We have learned the related concepts of OSI reference model. Now let's take a look at how TCP / IP protocol implements the network model compared with the seven layer protocol reference model. Layer functions in OSI: TCP / IP protocol family
application layer file transfer, e-mail, file service, virtual terminal, TFTP, HTTP, SNMP, FTP, SMTP, DNS, rip, telnet
presentation layer data format, code conversion, There is no protocol for data encryption
there is no protocol for session layer to release or establish contact with other nodes
the transport layer provides end-to-end interfaces TCP, UDP
the network layer selects routing IP, ICMP, OSPF, BGP, IGMP, ARP, RARP for data packets
the data link layer transmits addressable frames and error detection functions slip, CSLIP, PPP, MTU
the physical layer transmits data iso2110 and IEEE802 on the physical media in the form of binary data. Ieee802.2
data link layer includes hardware interface and protocols ARP and RARP
As we all know, blockchain is the proct of recent years, but the market for blockchain related courses can be said to be multifarious, fengmaolingjiao, each has its own merits, here, do a statistics, study, discuss and exchange together
32. What is the application of blockchain (decentralized application)
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the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system
main learning contents and tasks:
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3. Design system application scheme, process, model, etc
4. Test the function, safety and stability of the system
5. Operate the system application on the blockchain service platform
6. Collect and summarize the problems in the application of the system
7. Application, self use and promotion of blockchain system
different people have different opinions on the gold content. Now, with the rapid development of blockchain, it is better to learn more knowledge than to be abandoned by the times.