Devices that use DMA provide one significant advantage over devices that do not. What is this advantage?
A) Devices that can use DMA are designed for low power consumption, making them perfect for laptops.
B) DMA-capable hard drives have much higher seek times than those drives that don’t support DMA.
C) A device that supports DMA supports faster CPUs than those devices without DMA support.
D) A DMA-capable device can communicate directly with memory, bypassing the CPU.
Answer: D) A DMA-capable device can communicate directly with memory, bypassing the CPU.
DMA is an abbreviation for direct memory address. As the name implies, devices that support DMA have the advantage of communicating directly to memory. DMA is usually supported in devices that communicate often to memory, such as hard drives. Not all devices support DMA.
The incorrect answers:
A) Devices that can use DMA are designed for low power consumption, making them perfect for laptops.
DMA-capable devices are useful for both laptops and desktops, but not because they offer any particular advantages or disadvantages related to power consumption.
B) DMA-capable hard drives have much higher seek times than those drives that don’t support DMA.
A hard drive is a mechanical device, and laws of physics will always apply. The seek time for a hard drive is unrelated to the communications path between the hard drive and memory.
C) A device that supports DMA can use faster CPUs than those devices without DMA support.
Since the point of DMA is to avoid the CPU entirely, the speed of the CPU is irrelevant to the use of DMA.
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Want to know more? Watch “System Resources: I/O, IRQ, and DMA.”If you’ve ever looked into the details of the Windows Device Manager, then you’ve probably seen references to I/O addresses, IRQ values, and DMA settings. In this video, we’ll explain what all of these abbreviations mean and show you how the Windows Device Manager can be used to view and modify the system resources in your personal computer. |