What does DMA stand for?
| Full form | Direct Memory Access |
|---|---|
| Category | Technology & computing |
| Type | Initialism |
The initialism DMA stands for Direct Memory Access in computing. It lets supported hardware transfer data involving memory without the CPU performing every individual transfer operation.
A peripheral-to-memory or memory-to-memory transfer is a data-movement task. The CPU can still be involved in setup, coordination and completion handling. A transfer count and the size of each item are separate quantities: a count of 64 two-byte items describes 128 bytes in a simple same-width example. That arithmetic does not establish the transfer configuration, performance or capabilities of a particular controller.
Meaning in context
- Direct
- Describes the supported hardware access path in this computing term; it does not mean every CPU responsibility disappears.
- Memory Access
- The data movement involves memory. Direction and item widths remain configuration-specific details.
Practical examples
Count the bytes
- Before
64 items always means 64 bytes.
- After
In our fictional same-width example, 64 items at 2 bytes per item total 128 bytes.
The item count becomes a byte count only after the item width is specified.
Describe CPU involvement
- Before
DMA means the CPU has no work associated with the transfer.
- After
DMA can perform the data movement independently of per-item CPU copying; setup and completion handling remain separate questions.
Avoid turning an access mechanism into a universal zero-overhead claim.
Original illustrative examples, not quotations or reports of actual events.
Use DMA with clarity
When a DMA example lists a count, how do I avoid mistaking items for bytes?
See all guidance
Explain the direction
State which endpoints the example uses.
The invented transfer moves data from a peripheral to memory.
Read a count
Name the item width before converting to bytes.
64 items at 2 bytes each represent 128 bytes.
Discuss performance
Separate mechanism from a measured timing result.
DMA support alone does not state the achieved throughput.
Try changing the item width while keeping the count unchanged; observe which quantity changes.
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By AcronymIndex Editorial Team · Editorial policy