Abstract: In a multichannel seismic system, channel-sequential seismic data samples gathered during a first recording cycle are demultiplexed to sample-sequential format in a core memory. The core memory is divided into pages each of which is addressable in two dimensions by rows and columns as a rectangular matrix. The channel-sequential data samples are serially loaded into the respective pages in channel-sequential order by columns. At the end of the first recording cycle, the data are extracted from the respective pages by rows in sample-sequential order. As the data samples from the first recording cycle are being extracted by rows, data samples from a second recording cycle are loaded serially by rows into the respective pages that were vacated by the extracted data samples of the first recording cycle.