Technologies are described herein for recovering data in a storage device comprising a controller and a plurality of storage units. The controller receives a data stream, and divides the data stream into a plurality of data blocks, obtains a code block using the plurality of data blocks. When there is one or more blocks with damaged data in the plurality of data blocks and the code block, the controller obtains a sub-block from the Mth bit to the Nth bit of each block in the plurality of data blocks and the code block as a set, and reconstructs data in one or more sub-blocks with damaged data using other sub-blocks with undamaged data in the set.