A method of correcting optical coherence tomography image data obtained from a layered media sample includes identifying at least one interface from the obtained OCT data and correcting the OCT data for distortion at the at least one interface. Coherency control circuitry manages data coherence between data items which may be stored within a cache memory andor a further memory. IO operations are tracked by incrementing the counter value when an IO operation is received and decrementing the counter value when an IO operation is processed. Air-bearing portions are configured to fly nearest to a magnetic-recording disk; shallow-recessed surfaces have a first depth from the air-bearing portions; the deep-recessed surface has a second depth, larger than the first depth, from the air-bearing portions. In particular, the novel materials are porous inorganicorganic hybrid monolith materials, which desirably may be surface modified, and which offer more efficient chromatographic separations than that known in the art.