, Volume 18, Issue 3, pp 283-305

First online:

On the Influence of Lookahead in Competitive Paging Algorithms

  • S. AlbersAffiliated with{Max-Planck-Institut für Informatik, Im Stadtwald, 66123 Saarbrücken, Germany.}

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We introduce a new model of lookahead for on-line paging algorithms and study several algorithms using this model. A paging algorithm is n-line with strong lookahead l if it sees the present request and a sequence of future requests that contains l pairwise distinct pages. We show that strong lookahead has practical as well as theoretical importance and improves the competitive factors of on-line paging algorithms. This is the first model of lookahead having such properties. In addition to lower bounds we present a number of deterministic and randomized on-line paging algorithms with strong lookahead which are optimal or nearly optimal.

Key words. On-line algorithms, Paging, Lookahead, Competitive analysis.