On write-unidirectional memory codes

Write-unidirectional memories generalize write-once memories storing binary sequences of some fixed length in a reusable manner. At every new usage the content of the memory can be rewritten by either changing some of the zeroes to ones or changing some of the ones to zeroes, but not both. The author constructs codes of rate 0.5325. He discusses the four cases that arise according to whether or not the encoder and/or the decoder is informed of the previous state of the memory. J.M. Borden´s converse bound (submitted to IEEE Trans. Inf. Theory) is rederived using Fibonacci sequences