Let be the group of binary d-tuples. The authors study the process with , A fixed in and a random vector of disturbance terms. This model algorithms in the presence of a ‘bad bit’. For a class of situations the authors show that the distribution of tends to the uniform distribution on . They determine sharp rates of convergence and demonstrate the existence of cutoff phenomena. The analysis depends on understanding codes made from the binomial coefficients (mod 2). It leads to a novel type of oscillating behavior for the location of the cutoff and for the error terms.
