The lowest layer SAL shielded the differences among operating systems, the API layer made the interfaces stable and easily used, and the middle layer DRV was the main part of the driver.是什么意思_The lowest layer SAL shielded the differences among operating systems, the API layer made the interfaces stable and easily used, and the middle layer DRV was the main part of the driver.在线翻译_英语_读音_用法_例句