LFCS · Question #748
What information is displayed by the command cat/proc/dma?
The correct answer is B. which DMA channels are in use. The /proc/dma file in Linux provides information about the DMA channels currently registered and in use by various devices.
Question
Options
- Awhether DMA is enabled
- Bwhich DMA channels are in use
- Cwhich DMA mode is in use
- Dgeneral information about DMA on the machine
How the community answered
(38 responses)- A5% (2)
- B89% (34)
- C3% (1)
- D3% (1)
Why each option
The `/proc/dma` file in Linux provides information about the DMA channels currently registered and in use by various devices.
`/proc/dma` lists allocated channels, not a general status of whether DMA is enabled globally.
The `/proc/dma` virtual file displays a list of the Direct Memory Access (DMA) channels that are currently registered and claimed by devices within the system. It shows which device is using which DMA channel, which is crucial for troubleshooting hardware conflicts or understanding resource allocation.
While it shows usage, it does not detail the specific DMA *mode* (e.g., burst, single-cycle) for each channel.
While it provides *some* general information, its specific purpose is to list *in-use* channels, not a comprehensive overview of DMA capabilities or configuration.
Concept tested: Linux /proc filesystem (DMA)
Source: https://learn.microsoft.com/en-us/windows-server/administration/linux-reference/linux-commands/proc
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