Generalized definition of distributed computing: study how to put a very large computing power is needed to solve the problem is divided into many small parts, and then put the part assigned to many computer processing, finally the results together to get the final result,

Recently distributed computing projects has been used for hundreds of thousands of volunteers from all over the world to use computer of idle capacity, through the Internet, you can analyze the electrical signal from outer space, to find hidden black holes, and explore the possible existence of alien life wisdom; Can be looking for more than 10 million digital mason prime Numbers; Can also search for and find more effective drugs against HIV, these projects are very large, need tremendous amount of calculation, just by a single computer or individual in a can let a person to accept time calculation done is out of the question,

The definition of the Chinese Academy of Sciences
In two or more software to share information with each other, the software can run on the same machine, can also be connected through the network to run on multiple computers, distributed computing, compared with other algorithm has the following advantages:
1, scarce resources can be Shared,
2, can be on multiple computers by distributed computing load balance calculation,
3, can put the program on the computer is most suited to running it,
Among them, the sharing of rare resources and balance load is one of the core of the computer distributed computing,

Cloud computing advantages: large scale, virtualization, high reliability, versatility, high scalability, on-demand service, extremely cheap, fault tolerance,

Parallel computing, parallel computing means for multiple tasks at the same time or multiple instructions, or to deal with multiple data items, complete the processing of computer system is called parallel computer system, it is the multiple processors through network connection orderly organized in a certain way,

Cloud computing: cloud computing (cloud computing) is a kind of distributed computing, refers to the "cloud" through the network will be huge data processing program is decomposed into thousands of small programs, and then, through a number of servers for the processing and analysis system of the small program to get the results, and returned to the user, early cloud computing, in a nutshell, is a simple distributed computing, solve the task distribution, and calculation results of merger, as a result, cloud computing is also called grid computing, using this technology, can be in a very short period of time (seconds) of tens of thousands of data processing, so as to achieve a powerful network service,

Distributed systems: the definition of a distributed system (distributed system) is a software system based on network, it is because the characteristics of the software, so the distributed system has a high degree of cohesiveness and transparency, so more of the difference between a network and a distributed system lies with the top software (especially the operating system), rather than hardware,

The characteristics of the distributed system: reliability, scalability, availability, efficiency,

Cap theory that for a distributed system, can't meet the following 3 points: consistency, availability, partition tolerance,

Deadlock: a deadlock refers to two or more than two processes in the process of execution, due to competition resources or due to communicate with each other a blocking phenomenon, without external force, they will not be able to push down, the said system in a deadlock state or system to produce the deadlock, the process, is called a deadlock in the process of waiting for each other forever,