DMA(Direct Memory Access)

What is DMA, and why is it needed?

DMA (Direct Memory Access) allows data to be transferred directly between devices (like a hard drive) and memory, without going through the CPU. In simple terms, instead of the CPU handling the task of moving data, DMA takes care of it, so the CPU can focus on other important tasks.

Why is DMA important?

• Faster processing: Since the CPU doesn't have to move data manually, the system can work faster.
• Less CPU load: The CPU is free to handle more critical tasks while DMA manages the data transfer.

How DMA works:

1. A device wants to send data: For example, when a hard drive wants to move data to memory.
2. The DMA controller takes action: The CPU tells the DMA controller, "Move this data," and the DMA controller starts the process.
3. DMA transfers data: The DMA controller moves data directly from the hard drive to the memory.
4. CPU stays focused: While DMA is moving data, the CPU can continue working on other tasks.

reference

• https://velog.io/@sieunpark/OS-DMA%EB%A9%94%EB%AA%A8%EB%A6%AC-%EC%A7%81OS-DMA-%EB%A9%94%EB%AA%A8%EB%A6%AC-%EC%A7%81%EC%A0%91-%EC%A0%91%EA%B7%BC