There is provided a convolution operation circuit that performs a convolution operation on a provided digital signal. The apparatus includes a nonvolatile memory located within the hybrid hard disk, a loading unit reading data of a fragmented cluster and temporarily storing the read data in the nonvolatile memory, and a writing unit writing the temporarily stored data in contiguous clusters. The added weighted multiples may be from neighboring sub-carriers in the same symbol andor from other symbols in a tone, for example, a previous or next symbol. The stress reduction can result in the members withstanding the additional dynamic load caused by a catamaran system without increasing member sizes adequate for an offloading operation.