Belady Anomaly

”Usually, if you increase the number of frames allocated to a process in virtual memory the chances to receive fewer page faults increase. Sometimes the opposite happens and the phenomenon is called Belady’s Anomaly.

This phenomenon is experienced to a greater or lesser extent in page replacement algorithms such as First In First Out (FIFO), Second Chance Algorithm and Random Page Replacement Algorithm.

Although algorithms that do not suffer from this anomaly are being used too, such as LRU or Optimal Page Replacement – that follow the stack algorithm property, the anomaly is still a topic of interest for research.” Ștefan Iliescu – Chief Data Scientist at Metaminds.