DMA-Direct memory access

DMA (Wikipedia), allows certain hardware subsystems within the computer to access system memory for reading and/or writing independently of the central processing unit (CPU).

W/o DMA, using programmed I/O (PIO) to load/store instructions for multicore chips, or to communicate with peripheral devices, CPU is typically fully occupied during the R/W operations.

With DMA, the CPU would initiate the transfer, do other operations while the transfer is in progress, and receive an interrupt from the DMA controller once the operation has been done.

Introduction to DMA