求助：关于KeStallExecutionProcessor这个函数

这个函数在文档里面的解释有这么一句话：

KeStallExecutionProcessor is a processor-dependent routine thatbusy-waits for at least the specified number of microseconds, but notsignificantly longer.This routine is for use by device drivers and other software that must wait foran interval of less than a clock tick but more than for a few instructions.

这里我就看不懂了，这个函数的参数却是以毫秒为单位，一个clock tick不是10纳秒吗。怎么第二句话说less than a clock tick？

还有关于键盘端口的。键盘的数据端口是0x60还是0x64？还是两个都可以。

高手帮忙呀。谢谢了！！！！！！！！