Short for
direct memory access, a technique for transferring
data from
main memory to a
device without passing it through the
CPU.
Computers that have DMA
channels can transfer data to and from devices much more quickly than computers without a DMA channel can. This is useful for making quick
backups and for
real-time applications.
Some expansion boards, such as CD-ROM cards, are capable of accessing the computer's DMA channel. When you install the board, you must specify which DMA channel is to be used, which sometimes involves setting a jumper or DIP switch.