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Caching or Demand Paging

By mikeetee ·
In the NCSE mock tests there is a question on demand paging or caching..... Is there a great difference within the Virtual Memory Machine in Windows NT?

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Caching or Demand Paging

by AlanTheTech In reply to Caching or Demand Paging

Virtual Memory Paging is a technique to use hard drive space as RAM, which it loads which ever memory page into physical RAM what it actually needs to use it. This method is used because it is a whole lot cheaper to have 1GB of "hard drive ram" than to actually purchase "physical ram". It also happens to be a whole lot slower than actual RAM.

Hard Drive Caching is using RAM as a ultra-fast hard drive when re-reading data that has been recently been used. This technique speeds up disk access by a considerable amount if the data is already cached in memory. It does not help (and actually is more overhead) when the data hasn't already been read.

The two terms are almost antonyms. Hard drive caching is using ram instead of hard drives and Virtual Memory Paging uses hard drives as RAM.

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