Writing and reading of data in probe-based data storage devices

An apparatus for controlling reading and writing of user data in an array of A.sub.d storage fields of a probe-based data storage device in which data is written to and read from the array of storage fields by a corresponding array of probes, the apparatus comprising:

• a codeword generator for coding blocks of user data to produce, from each user data block, a plurality of C-byte codewords such that r*C=k.sub.1*As where r is the number of codewords, k.sub.1 is an integer.gtoreq.1, A.sub.s=A.sub.d/k.sub.0 and k.sub.0 is an integer.gtoreq.2;
• a sub-block generator for producing, for each user data block, As sub-blocks of k.sub.1 bytes from the r codewords produced from that user data block by selecting successive bytes of each sub-block cyclically from the r codewords;
• and a read/write controller for controlling writing, for successive groups of k.sub.0 user data blocks, of the A.sub.s sub-blocks produced from each of the k.sub.0 blocks to a respective sub-array (SA1 to SA k.sub.0), of A.sub.s storage fields, of the storage field array by selectively controlling writing to the sub-arrays (SA1 to SA k.sub.0) at one of a series of rates, ranging from 1 sub-array at a time to k.sub.0 sub-arrays at a time, in dependence on a desired data write-rate, such that the A.sub.s sub-blocks written to each sub-array (SA1 to SAk.sub.0) are written via respective probes to the corresponding storage fields of the sub-array, and for controlling reading of the sub-blocks from the sub-arrays (SA1 to SA k.sub.0) by selectively controlling reading at one of a series of rates, ranging from 1 sub-array at a time to k.sub.0 sub-arrays at a time, in dependence on a desired data read-rate.