Flash storage device and data writing method thereof

Abstract

A flash storage device comprises a flash memory and a controller. The flash memory comprises a plurality of blocks comprising a plurality of ordinary pages and a plurality of reserved pages. The controller receives a current write command and write data from a host, determines a mother block and an FAT block corresponding to the write command, divides data of the mother block and data of the FAT block into a plurality of original data segments and a plurality of updating data segments, integrates the original data segments with the updating data segments to obtain integrated data segments, writes the integrated data segments to an integrated block respectively in a plurality of processing periods of a plurality of subsequent write commands, and writes the subsequent write data to the reserved pages of a plurality of subsequent blocks.