New upper and lower bounds on the channel capacity of read/write isolated memory

In this paper, we re3ne upper and lower bounds for the channel capacity of a serial, binary rewritable medium in which no consecutive locations may store 1’s and no consecutive locations may be altered during a single rewriting pass. This problem was originally examined by Cohn (Discrete. Appl. Math. 56 (1995) 1) who proved that C, the channel capacity of the memory, in bits per symbol per rewrite, satis3es 0:50913 · · ·6C6 0:56029 · · · : In this paper, we show how to model the problem as a constrained two-dimensional binary matrix problem and then modify recent techniques for dealing with such matrices to derive improved bounds of 0:53500 · · ·6C6 0:55209 · · · : ? 2003 Elsevier B.V. All rights reserved.