Comparing with programmed I/O, interrupt-driven I/O further raises the usage rate of CPU operations, because __________
A: it isn’t necessary for CPU to save and restore scene
B: it isn’t necessary for CPU to intervene the dada transfer
C: it isn’t necessary for CPU to read and check status repeatedly
D: both A and B
A: it isn’t necessary for CPU to save and restore scene
B: it isn’t necessary for CPU to intervene the dada transfer
C: it isn’t necessary for CPU to read and check status repeatedly
D: both A and B
举一反三
- He isn't necessary any longer.
- don't need to A: used to say it isn't necessary to do something B: used to say that somthing is necessary C: used to say something is a good idea D: used to say something isn't a good idea
- They don’t seem to answer the phone when I call; there isn’t anyone at home, _______? A: isn’t there B: is there C: is it D: isn’t it
- In the _____ method for synchronizing the operation of the CPU with an I/O device, a large block of data can be passed from an I/O device to memory directly. A: isolated I/O B: DMA C: interrupt-driven I/O D: programmed I/O
- This is my first time that I have come to America, ___________? A: haven't I B: have I C: isn't it D: isn't this