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Page Replacement Policies (cont)

Cost benefit from buffer pool (with n frames) is determined by:
  • number of available frames (more ⇒ better)
  • replacement strategy vs page access pattern
Example (a): sequential scan, LRU or MRU, n ≥ b

First scan costs b reads; subsequent scans are "free".

Example (b): sequential scan, MRU, n < b

First scan costs b reads; subsequent scans cost b - n reads.

Example (c): sequential scan, LRU, n < b

All scans cost b reads; known as sequential flooding.