How can I get read-ahead bytes?
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by Bruno Martinez
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Published on 2010-04-28T19:20:02Z
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2010/04/28
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Operating systems read from disk more than what a program actually requests, because a program is likely to need nearby information in the future. In my application, when I fetch an item from disk, I would like to show an interval of information around the element. There's a trade off between how much information I request and show, and speed. However, since the OS already reads more than what I requested, accessing these bytes already in memory is free. What API can I use to find out what's in the OS caches?
Alternatively, I could use memory mapped files. In that case, the problem reduces to finding out whether a page is swapped to disk or not. Can this be done in any common OS?
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