what is DMA? Explain the working principle of DMA.

•DMA is a technique for transferring blocks of data directly between two hardware devices.

•In the absence of DMA the processor must read the data from one device and write it to the other one byte or word at a time.

•DMA Absence Disadvantage: If the amount of data to be transferred is large or frequency of transfer is high the rest of the software might never get a chance to run.

•DMA Presence Advantage: The DMA Controller performs entire transfer with little help from the Processor.