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Module 6 · Concurrency, OS, ML Interview Topics
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OS: virtual memory & page cache
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📝 **Question:** Why is `cat huge_file > /dev/null` faster the second time? 📋 Pick the right answer. 💡 **Hint:** Re-read the theory above if unsure.
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📝 **Question:** Why is `cat huge_file > /dev/null` faster the second time? 📋 Pick the right answer. 💡 **Hint:** Re-read the theory above if unsure.
A
The disk warmed up — NVMe wear-levelling moves hot blocks to faster cells after the first access.
B
Page cache — file's pages are in RAM now; second read is memory-speed, no disk IO.
C
The shell compiles `cat` into a binary plan on first invocation and the AST is reused on the second.
D
It doesn't — both runs hit the same disk path so any apparent speedup is statistical noise.
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