Discuss DMA definition.
Direct memory access (DMA) is a process wherein an external device takes over the control of system bus by the CPU. Direct memory access is for high-speed data transfer by mass storage peripherals, for illustration magnetic tape, hard disk drive, CD-ROM and sometimes video controllers. For instance, a hard disk may boast a transfer rate of 5 M bytes per second, which is 1 byte transmission every 200 ns. To make that data transfer with the CPU is both undesirable and unessential.