CACHE BUFFER CONTROL METHOD AND CONTROLLER

摘要

PROBLEM TO BE SOLVED: To provide improved cache buffer control for a storage device having a nonvolatile memory medium. SOLUTION: A memory cell of a cache buffer is logically divided into many pages. If a plurality (usually all) of memory cells in a page can store new data, an open condition is registered in a counter in the page. If a memory cell in a page cannot store new data, a full condition is registered in a counter in the page. New data is stored in the page which is registered as the open condition in its counter. The page is weighted based on a reading command rate to give order of priority for the purpose of reading and writing.