DMA means Direct Memory Access ,When large amount of data are to be moved,a more efficient technique
is DMA.Block of data are transferred between an external device and the main memory,without continuous intervention by the processor.
- DMA channels are used to communicate data between the peripheral device and the system memory
- Without the DMA channels, the CPU copies every piece of data using a peripheral bus from the I/O device. Using a peripheral bus occupies the CPU during the read/write process and does not allow other work to be performed until the operation is completed.
- With DMA, the CPU can process other tasks while data transfer is being performed. The transfer of data is first initiated by the CPU. During the transfer of data between the DMA channel and I/O device, the CPU performs other tasks. When the data transfer is complete, the CPU receives an interrupt request from the DMA controller
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