多线程------外文翻译.docVIP

Multi-thread Multithreaded overview In computer programming, a basic concept of multiple tasks at the same time try to control. Many of the programs are required to design program can stop the job in hand, to deal with other problems, again to return to main process. Through various ways to achieve this objective. In the beginning, the master machine low-level languages of programmers to write some interrupt service routines, the main process is suspended by the interruption of the hardware level to realize. Although this is a useful method, but make up the transplant program is hard, which caused the other kind of costly problems. Interrupt for those very strong missions real-time is very necessary. But for many other problems, only request will be divided into independent operation of the procedure of pieces, make the process can more quickly respond to user request. In the beginning, thread is only for a single processor allocation of the processing time of a kind of tool. But if the operating system itself support multiple processors, so each thread can be assigned to a different processor, really get into parallel computing state. From the point of view of a programming language, multi-thread most valuable characteristics operation is one of programmers need not be concerned with how much exactly a processor. Program in logical significance is divided on a thread; If the machine itself installed the multiple processors, so program will run faster, no need to make any special adjustments. According to the front discussed, you may feel thread treatment is very simple. But must pay attention to a problem: sharing resources! If there are multiple threads and operation, and they tried to access the same resources, will meet a problem. For example, the two threads will not information also send a printer. To solve this problem, for those who can be Shared resources for them in use period must go into the locked state. So a thread can lock resources, in the completed