A method for writing and reading data in a main nonvolatile memory having target pages in which data are to be written and read, the method including providing a nonvolatile buffer having an erased area, providing a volatile cache memory, and receiving a write command to update a target page with updating data the length of which can be lower than the length of a page. The method also includes, in response to the write command, writing the updating data into the erased area of the nonvolatile buffer, together with management data of a first type, and recording an updated version of the target page in the cache memory or updating in the cache memory a previously updated version of the target page.