Reason for introducing concurrency

Here I don't want to talk about the development history of the operating system, but I want to talk about the reason why concurrency is urgently introduced during the development of the operating system:

1. Resource Utilization sometimes, ProgramAt work, you must wait for an external operation to end before proceeding to the next step, for example, while waiting for input and output, while the program is waiting, you cannot do any other work. Therefore, if the program executes another program while waiting, it will undoubtedly improve the efficiency of program execution. In elementary school, Hua Luogeng's overall planning method also talked about the utilization rate, which gives me the same inspiration. 2. Fairness in most cases, we require different programs to have the same right to use computers. Therefore, an efficient AlgorithmTo solve this problem. The time-sharing operating system refers to sharding the CPU time of a computer in a coarse-grained manner, and then sharing resources with different programs. 3. A multi-task operating system is convenient, providing direct communication and interaction for multiple programs. The direct communication of programs makes the program structure more flexible, and complicated tasks can be split in the past, solving many practical problems in the past.