XK0-004 · Question #65
Which of the following statements is correct when talking about /proc/?
The correct answer is C. All changes to files in /proc/ are immediately recognized by the kernel. The /proc filesystem is a virtual, in-memory interface to the running kernel, and writing to writable files within it (such as those under /proc/sys/) takes effect immediately without requiring a reboot.
Question
Which of the following statements is correct when talking about /proc/?
Options
- AAll changes to files in /proc/ are stored in /etc/proc.d/ and restored on reboot.
- BAll files within /proc/ are read-only and their contents cannot be changed.
- CAll changes to files in /proc/ are immediately recognized by the kernel.
- DAll files within /proc/ are only readable by the root user.
How the community answered
(36 responses)- A3% (1)
- B3% (1)
- C86% (31)
- D8% (3)
Why each option
The /proc filesystem is a virtual, in-memory interface to the running kernel, and writing to writable files within it (such as those under /proc/sys/) takes effect immediately without requiring a reboot.
/proc is an in-memory virtual filesystem with no persistence mechanism; no directory like /etc/proc.d/ exists to store changes, and nothing is restored on reboot.
Many files in /proc/ are writable - for example, /proc/sys/ entries are designed to be written to in order to tune kernel parameters at runtime.
Because /proc is a virtual filesystem backed directly by the kernel, writes to writable entries like /proc/sys/net/ipv4/ip_forward are processed in real time by the kernel. There is no disk write or cache layer - the change is applied the moment the write system call completes.
Many /proc/ entries are world-readable by design so that regular users and tools can query system state (e.g., /proc/cpuinfo, /proc/meminfo).
Concept tested: Linux /proc virtual filesystem and kernel interaction
Source: https://www.kernel.org/doc/html/latest/filesystems/proc.html
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