Definition: DMA

(1) (Digital Media Adapter) See digital media hub.

(2) (Document Management Alliance) A specification that provides a common interface for accessing and searching document databases. It provides interoperability between multivendor document management systems. DMA was released in 1998 by the DMA task group of the AIIM association. See AIIM.

(3) (Direct Memory Access) Transferring data between memory and peripheral devices or from memory to memory without going through the CPU. Although DMA technologies may periodically steal cycles from the CPU, data are transferred much faster than using the CPU to control every byte of transfer.

Old ISA buses used 8-bit and 16-bit DMA channels, while PCI can take control and access system memory directly. New Xeon chips call their DMA the I/O Acceleration Technology (IOACT), and ARM's DMA is part of its Advanced Microcontroller Bus Architecture (AMBA) for connecting system-on-chip components (see SOC).

DMA Disk Transfers

IDE disk drives can transfer data via DMA or the Programmed I/O mode.