A system and method is disclosed for improving data integrity and the efficiency of data storage in separate memories of a computing device. In particular, the present invention introduces a combination of two types of memory, namely, an NVRAM and a Flash memory, as persistent memory for storing file data. By constantly caching a last data portion of a data file in an NVRAM, it avoids any sector erasing for individual bits in a Flash memory. Such an approach increases the data storage efficiency and life expectancy of a Flash memory. The present invention has very broad application in almost all computing devices, including any PC (desktop or laptop) and server computers. It demonstrates particularly advantageous performance in portable electronic devices implementing Windows.TM. CE operating systems.