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DMA, or Direct Memory Access, is a computer system feature that allows hardware subsystems to access the main memory independently of the Central Processing Unit (CPU). This bypasses the CPU for data transfers between memory and peripheral devices like graphics cards, sound cards, and network adapters, which speeds up the process and reduces the CPU's workload. The CPU initiates the transfer and is then free to perform other tasks until the operation is complete, at which point a DMA controller notifies the CPU.

How it works

CPU initiates: The CPU starts a data transfer by sending a command to a dedicated DMA controller.

Direct transfer: The DMA controller takes over and manages the transfer of data directly between the peripheral device and the main memory.

CPU is freed: While the transfer is happening, the CPU is free to perform other operations without being stalled.

Notification: Once the transfer is complete, the DMA controller sends an interrupt to the CPU to let it know the operation is finished.