OS & Hardware

What is the state called in which physical memory is so short that pages are constantly evicted and reloaded and little work gets done?

  1. ADeadlock
  2. BCache coherence
  3. CThrashing
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Answer: C. Thrashing

When the combined working sets of running processes exceed physical memory, loading a needed page evicts a page another process needs, which is then needed again almost immediately. Time is spent waiting on disk I/O and CPU utilization falls. This is thrashing, relieved by running fewer processes or adding memory. Deadlock is when tasks stop because each waits for resources held by the other.

  • A. Deadlock is tasks stopping while waiting on each other's resources.
  • B. Cache coherence concerns consistency of cache contents.
  • C. Correct. It is constant page swapping due to memory shortage.
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