Ethereum can completely replace the current client server mode

1. 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)

2. 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

3. Client / server structure, referred to as C / S structure, is a kind of software system architecture. It is one of the two most popular mainstream software architectures first developed by American Borland company, and the other is browser / server (B / s) structure developed by American Microsoft company. The server side generally uses high-performance computer, and cooperate with Oracle, Sybase and other large databases; The client needs to install special software. In this structure, we can balance the service processing capacity between the server and the client, but because the client has installed special software, there are certain restrictions on the platform, and the workload of installation and maintenance is heavy.

4. The client / server mode is to divide the network application into two parts, which are called front-end and back-end. The front-end program is loaded on the client computer, which is responsible for executing the executable program required by the client and feeding back the content returned by the server to the client; The back-end program is loaded on the server and runs heavy data processing program on the server to provide various services for multiple clients simultaneously. Therefore, it also has the functions of concurrency control and data integrity guarantee
advantages: in the application of file server, applications and data are concentrated on the shared file server. When users need services, the corresponding applications and data files are downloaded from the file server to the user's computer. If a large number of users require similar services, the network traffic will be increased catastrophic. Now, because the server can centrally process the services required by users, users with slow computers can use the shared server to provide high-speed computing power

5. Client / server mode, also known as C / S mode, is a kind of software system structure. It is an application system based on the internal network of the enterprise, which can give full play to the processing ability of the client. The corresponding advantages are fast response and high security of the client

6. The client is used by you, the server is used to access data, and the host is used to manage data.

7. When installing the Windows Server 2003 operating system, you must select the client license mode. Each of the installed Windows Server 2003 software requires a server license. In addition, each user or device (or a combination of both) accessing the server requires a Windows Server 2003 client access license. Unauthorized access to the server does not require a Windows client access license, such as unauthorized users browsing public web sites hosted on the server. Authorized access refers to the exchange of user or application credentials between the server operating system and the user or device
difference: Reference http://wenku..com/view/953839d97f1922791688e821.html

8. Client server model (C / S structure) is a kind of network architecture, which distinguishes client from server. Each instance of client software can make a request to a server or application server
browser / server mode (B / S structure for short) is a network structure mode after the rise of web. Web browser is the most important application software of client. This mode unifies the client, centralizes the core part of the system function to the server, and simplifies the development, maintenance and use of the system.

9.

1. C / S structure is a client / server structure. The relationship between client and server is master-slave, which is a one to many mode. Its information and data need to be saved on the server. If users want to browse and download information, they must first visit the server to browse and download information, and there is no interaction ability between clients. On the contrary, P2P mode does not provide information server and information client, each computer is the information publisher and information requester, peers can interact without using the server

In the C / S mode, the storage and management of information is centralized and stable. The server only publishes the information that users want to publish, and it will be kept in the server for a period of time. The server usually runs between networks without interruption. However, P2P lacks security mechanism. P2P can bring convenience to users, but it will also bring a lot of junk information, and each peer can enter or exit the network at will, which will cause network instability

3. From the security point of view, because the system will be vulnerable, and the C / S mode adopts the centralized management mode, the client can only passively obtain information from the server, so once the client makes an error, it will not affect the whole system

The management software of C / S mode is updated rapidly. To keep up with the technology, a lot of energy and money must be spent on the software updating, and the staff also need to spend a lot of money to maintain the server and database. On the contrary, P2P does not need a server, so it does not need to spend a lot of money, and each peer can publish and share information on the network, which makes full use of idle resources

10. C / S is also called client / server or client / server mode. The server usually uses high-performance PC, workstation or minicomputer, and uses large database system, such as Oracle, Sybase, Informix or SQL server. The client needs to install special client software
the advantage of C / S is that it can give full play to the processing power of the client PC, and a lot of work can be submitted to the server after being processed by the client. The corresponding advantage is that the client response speed is fast. The disadvantages are as follows:

only applicable to LAN. With the rapid development of the Internet, mobile office and distributed office become more and more popular, which requires our system to have scalability. This way of remote access needs special technology, and at the same time, it needs special design of the system to deal with distributed data

the client needs to install special client software. First of all, it involves the workload of installation. Secondly, if any computer has problems, such as virus and hardware damage, it needs to be installed or maintained. Especially when there are many branches or stores, it's not a matter of workload, it's a matter of distance. In addition, when the system software is upgraded, each client needs to be re installed, and its maintenance and upgrade costs are very high

there are also restrictions on the operating system of the client. It may work with Win98, but not with WIN2000 or Windows XP. Or not suitable for Microsoft's new operating system and so on, let alone Linux, UNIX and so on

for example, the game we play, the one we want to download from the client, is not a web game. Web games belong to B / S mode. For example, now QQ, world of Warcraft, do not have to install the client to play? If the server updates, you have to download the update package. Isn't this the typical C / S mode!!