Tuesday, July 9, 2013

Briefly explain DMA.



DMA is the abbreviation of Direct Memory Access. DMA is the feature of modern computer that allow certain hardware subsystem within the computer to access system memory independently of the CPU. Without DMA, when the CPU is using programmed input/output, it is typically full occupied for the entire duration of the read or write operation and thus is unavailable to perform other work. With DMA the CPU initiates the transfer, does other operations while the transfer is in progress, and receives an interrupt from the DMA controller when the operation is done. DMA can also be used in memory to memory transfer of data. DMA can offload expensive memory operation and increases the efficiency of the system.

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