A polymer comprising recurring units of formula or wherein R1, R2, R3 and R4 are H or C1-15 alkyl, R1 and R2, and R3 and R4, taken together, may form a ring; R5 and R6 are H, C1-15 alkyl, acyl or alkylsulfonyl groups or C2-15 alkoxycarbonyl or alkoxyalkyl groups which may have halogen substituents; and k0 or 1, and having a Mw of 1,000-500,000 is novel. The pump chamber has one way valves proximate each longitudinal end thereof. The first swapping module is configured to swap, in the transaction request, the plurality of interface select bits with selected bits of the address in the address field.