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Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU). [ 1 ] Without DMA, when the CPU is using programmed input/output , it is typically fully occupied for the entire duration of the read or write operation, and is thus ...
The Word DMA (WDMA) interface was the fastest method used to transfer data between the computer (through the Advanced Technology Attachment (ATA) controller) and an ATA device until Ultra Direct Memory Access (UDMA) was implemented.
A DMA attack is a type of side channel attack in computer security, in which an attacker can penetrate a computer or other device, by exploiting the presence of high-speed expansion ports that permit direct memory access (DMA).
In computing, an input–output memory management unit (IOMMU) is a memory management unit (MMU) connecting a direct-memory-access–capable (DMA-capable) I/O bus to the main memory. Like a traditional MMU, which translates CPU -visible virtual addresses to physical addresses , the IOMMU maps device-visible virtual addresses (also called device ...
In computing, remote direct memory access (RDMA) is a direct memory access from the memory of one computer into that of another without involving either one's operating system. This permits high-throughput, low- latency networking, which is especially useful in massively parallel computer clusters .
Under the Amiga architecture, the direct memory access (DMA) controller is integrated into the Agnus (Alice on AGA models) chip. Both the CPU and other members of the chipset have to arbitrate for access to shared RAM via Agnus. This allows the custom chips to perform video, audio, or other DMA operations independently of the CPU.
The Ultra DMA (Ultra Direct Memory Access, UDMA) modes were the fastest method used to transfer data through the ATA hard disk interface, usually between the computer and an ATA device. UDMA succeeded Single / Multiword DMA as the interface of choice between ATA devices and the computer.
Cycle stealing is difficult to achieve in modern systems due to many factors such as pipelining, where pre-fetch and concurrent elements are constantly accessing memory, leaving few predictable idle times to sneak in memory access. DMA is the only formal and predictable method for external devices to access RAM.