Abstract: A method for operating a data storage device having a data storage medium partitioned into blocks comprises. A binary value is assigned to each block, with the initial setting of each binary value to a first level. Subsequently the binary value assigned to each block into which data is written is set to the second level. In response to a request from a host to read data from a block, the binary value assigned to the block checked, and data from the block is read if the assigned binary value is set to the second level. An algorithm is executed to generate the data if the assigned binary value is set to the first level. The read data or the algorithm generated data is sent to the host.