This can happen at any number of places, but in the simplest case the OS is called on every tick of a clock, and decides which process should get the CPU for the next tick of the clock.

这个数字可以发生在任何地方，但在最简单的情况下操作系统被称为每滴答的时钟，并决定哪个进程应该得到CPU时钟的滴答。

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So, good to see that Apple has agreed to pay the Swiss Railways for the inclusion of their iconic clock design in the latest OS release from Apple.

FORBES: Apple Finally Pays For Some Intellectual Property