DMA stands for Direct Memory Access. DMA have ability in modern computers that permit peripheral devices to send data to the motherboard’s memory without interference from the CPU. To permit multitasking and speed up the computer operation the DMA is implemented in a computer bus. By using DMA the immediate computing applications in critical operations must be done concurrently. DMA are used in many hardware systems like floppy and disk drive controllers, graphic cards, network cards, sound cards and graphics processing units.
DMA is already enabled in our hard disk by default. A DMA transfer copies a block of memory from one device to another. By using DMA multiple memory areas data are transfer in a single DMA transaction. The DMA controller do not have any processing data, it just transfers the bytes as initiated in the configuration registers. DMA controller maintains the control of the bus until all the data buffered by the requesting device has been transferred to memory. DMA controllers have larger address registers than length registers.
