What is Direct Memory Access or DMA?
The method of transferring data from RAM or primary memory to another memory of a computer, especially in secondary memory and register memory, without informing the CPU or Computer Processing Unit is known as DMA or Direct Memory Access.
Any data input to the computer need to be processed by the CPU. But in some of the cases there is no need for processing of data. Like copy a data from RAM to HARDDISK. It is a dump job that is no robot science is needed. As processor is a busiest part of a computer, we can easily bypass that job through a DMA controlled IC. It increases the computer performance. Each input and output ports are assigned to a DMA channel.