Arbitrarily varying channels were introduced as a model for transmission in cases of jamming. We show that their theory also naturally applies to memories and yields in a unified way some new and all old Capacity Theorems for write-unidirectional (and more general) memories with side information. If the encoder has no side information it is still not understood what the optimal rates for many cycles are. We expect more insight from a theory of OV--channels, which we have introduced for that purpose and started to analyse