Counting in the presence of memory faults

Abstract

The faulty memory RAM presented by Finocchi and Italiano [1] is a variant of the RAM model where the content of any memory cell can get corrupted at any time, and corrupted cells cannot be distinguished from uncorrupted cells. An upper bound, δ, on the number of corruptions and O(1) reliable memory cells are provided. In this paper we investigate the fundamental problem of counting in faulty memory. Keeping many reliable counters in the faulty memory is easily done by replicating the value of each counter Θ(δ) times and paying Θ(δ) time every time a counter is queried or incremented. In this paper we decrease the expensive increment cost to o(δ) and present upper and lower bound tradeoffs decreasing the increment time at the cost of the accuracy of the counters. © 2009 Springer-Verlag Berlin Heidelberg.