Method, apparatus and storage medium for two-dimensional data storage

A method and an apparatus for reading a data pattern (1) from or writing a data pattern (1) to a storage medium (25) are described. During reading a pattern retrieval stage (21) retrieves (10, 12) a test pattern and the data pattern from the storage medium (25). A decoder (22), which is trained (11) with pattern elements of the retrieved test pattern by a training stage (23), decodes (13) the retrieved data pattern. During writing an encoder (42) generates the data pattern (1), whereas a test pattern generator (43) generates (31) a test pattern. The data pattern (1) and the test pattern are then stored (30, 32) on the storage medium (25) by a recording stage (44).