In DMA , the DMA module takes over the operations of data transferring from CPU, it means _____________.
A.the DMA module can fetch and execute instructions like CPU does
B. the DMA module can control the bus to transfer data to or from memory using stealing cycle technique
C.the DMA module and CPU work together(co-operate) to transfer data into or from memory
D.when DMA module get ready, it issues interrupt request signal to CPU for getting interrupt service
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Transfer data with I/O modules, 3 types of techniques can be used. Which doesn’t belong to them? _______.
A. Interrupt-driven I/O
B. Programmed I/O
C. Direct I/O access
DMA
Which I/O technique should be taken to output a data block of some sectors to hard disk? ___________
A. Interrupt-driven I/O
B. Programmed I/O
C. Direct I/O access
DMA
Which I/O technique should be taken to input a word from keyboard? __________
A. Interrupt-driven I/O
B. Programmed I/O
C. DMA
Direct I/O access
Comparing with interrupt-driven I/O, DMA 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
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