Research on computer time synchronization by software method

At present, computer clock synchronization among computers is usually realized through hardware method. It always result in high cost and inconvenient in practice, also it can only use in small-scale net. However, the software method has the advantage of lower cost and better flex, and is appropriate for the miniature distributed network and dynamic measurement areas whose synchronization precision acquired 10^-6 to 10^-3 second and absolute time is not necessary. In this paper, not only the theory of software method for time synchronization is introduced, but also the time synchronization is realized through this method. And the maximal timing delay source and time synchronization precision is analysed with measured data. The measured data shows that: the time error is within millisecond after 5 hours time-extension by using 3~5 minutes´ time comparison data.