What is a distributed system! ? What are the functions and benefits?

As the name implies, a distributed system is to frame the application layer, data layer or other parts of the system into a distributed (physical and logical) shape (usually a mesh). The design of distributed system is usually to enhance the scalability, stability and execution efficiency of the system. For example, online games are usually distributed systems, and the so-called "zone" is the subroutine in the distributed system. In fact, a distributed database can also be called a distributed system, and the data persistence layer is distributed (data exists in different databases and can interact with each other, and there is an integrated management system to maintain the integrity and accuracy of data).

Therefore, the distributed system is more accurately a concept of system architecture than a technology.

C# supports the network very well, and it is well packaged. You may mainly watch online communication. Then the Machinery Industry Press has a book about distributed systems, which is very comprehensive. You can have a look. ~

The following is the explanation given by Baidu Encyclopedia:

Distributed software system (distributed software system)

It is a software system that supports distributed processing, and it is a system that performs tasks on a multiprocessor architecture interconnected by a communication network. It includes distributed operating system, distributed programming language and its compilation (interpretation) system, distributed file system and distributed database system.

Distributed operating system is responsible for managing the resources of distributed processing system and controlling the running of distributed programs. The difference between it and centralized operating system lies in resource management, process communication and system structure.

Distributed programming languages are used to write distributed programs running on distributed computer systems. A distributed program consists of several program modules that can be executed independently, which are distributed on multiple computers in a distributed processing system and executed simultaneously. Compared with centralized programming language, it has three characteristics: distribution, communication and robustness.

Distributed file system has the ability to perform remote file access, and manages and accesses files distributed on the network in a transparent way.

Distributed database system is composed of multiple database systems distributed on multiple computer nodes, which provides effective access means to manipulate the sub-databases on these nodes. Distributed database can be regarded as a complete database in use, but it is actually distributed on geographically dispersed nodes. Of course, the sub-databases distributed on each node are logically related.

A distributed database system consists of multiple workstations. These stations, also called nodes, are connected together in a communication network. Each node is an independent database system, and they all have their own database, CPU, terminal and their own local database management system. Therefore, the distributed database system can be regarded as a combination of a series of centralized database systems. They belong to the same system logically, but they are distributed in physical structure.

Distributed database system has become an important field of information processing discipline and is developing rapidly for the following reasons:

1, which can solve the problem that organizations are scattered and data need to be related. For example, in the banking system, the head office and branches are located in different cities or different areas of cities, and they need to process their own data and exchange and process each other in business, which requires a distributed system.

2. If an organization needs to add new relatively autonomous organizational units to expand its organization, the distributed database system can expand with minimal impact on the current organization.

3, the need to balance the load. The decomposition of data maximizes the local application, thus minimizing the mutual interference between processors. By sharing the load between processors, serious bottlenecks can be avoided.

4. When multiple database systems already exist in existing institutions and the necessity of global application increases, these databases can form a bottom-up distributed database system.

5. The failure probability of the distributed database system with the same scale will not be lower than that of the centralized database system, but as the impact of its failure is limited to local data applications, the reliability of the whole system is relatively high.

trait

1. In the distributed database system, the concept of centralized control is not emphasized. It has a hierarchical control structure based on global database administrators, but each local database administrator has a high degree of autonomy.

2. The concept of data independence is equally important in distributed database system, but a new concept, distributed transparency, is added. The so-called distributed transparency means that when writing a program, it seems that the data is not distributed, so transferring the data will not affect the correctness of the program. But the execution speed of the program will be reduced.

3. Different from centralized database system, data redundancy is considered as an essential feature in distributed system. The reasons are as follows: First, if data is copied at the required nodes, local applicability can be improved. Secondly, when a node fails, it can operate the copied data on other nodes, so this can increase the effectiveness of the system. Of course, the evaluation of optimal redundancy in distributed systems is very complicated.

The types of distributed systems can be roughly divided into three categories:

1, distributed data, but only one main database, no local database.

2, layered processing, each layer has its own database.

3. There is no central control part in the fully distributed network, and there are many connection modes between nodes, such as loose connection, tight connection, dynamic connection and broadcast notification connection.

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What is distributed intelligence?

The distributed intelligence of NI LabVIEW 8 combines relevant technologies and tools to solve some challenges that will be encountered in the development of distributed systems. More importantly, the solution provided by distributed intelligence of NI LabVIEW 8 not only solves these challenges, but also is easy to implement. The distributed intelligence of LabVIEW 8 specifically includes:

All nodes in a distributed system can be programmed, including hosts and terminals. Especially valuable is that you can use LabVIEW to program a large number of different types of objects, such as desktop processor, real-time system, FPGA, PDA, embedded microprocessor and DSP.

Browse the view system of all system nodes. You can use the Project Browser to view, edit, run and debug nodes running on any object.

Simplified data sharing programming interface-* * * shared variables. With * * * shared variables, you can easily transfer data between systems, even between real-time systems, without affecting performance. No communication loop, no RT FIFO and no underlying TCP function. You can use simple dialogue to complete the configuration of * * * shared variables, so as to transfer data between systems or connect data to different data sources. You can also add data services, such as records, alerts and events-all in a simple conversation.

The synchronous operation within or between remote devices and systems is realized-timing and synchronization are always the key issues in defining high-performance measurement and control systems. Using the system based on NI technology, we explore the inside of the equipment and write its internal operation mechanism, so as to obtain a more flexible solution than traditional instruments or PLC.

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With the support of distributed computer operating system, interconnected computers can coordinate their work and accomplish a task together.

It can also be explained like this:

Computer hardware configuration mode and corresponding function configuration mode. It is a multi-processor computer system, and each processor forms a unified system through the Internet. The system adopts distributed computing structure, that is, the tasks handled by the central processor in the original system are assigned to the corresponding processors, so that processors with different functions can coordinate with each other and share the peripherals and software of the system. This speeds up the processing speed of the system and simplifies the logical structure of the host.

I hope it helps you ~:)