在单指令流单数据流结构中，有单一的指令周期，在执行前，单个处理机按序取操作数。

In an SISD architecture there is a single instruction cycle; operands are fetched serially into a single processing unit before execution.

youdao

但当我面对更加重要的操作数据时，可能需要更频繁地拍取该快照，也许是每六小时拍一次，甚至每小时拍一次。

But as I move into my more mission critical operating data, I may need to take that snapshot more often maybe every six hours, every four hours, maybe even every hour.

youdao