File structure for a non-volatile semiconductor memory

摘要

A non-volatile semiconductor memory comprises an active block for storing a first file, a reserve block for storing a second file, and a directory block. The second file is a copy of the first file. The copy is made during a clean-up operation prior to erasure of the active block. The directory block comprises a directory entry for identifying the first file. The file structure allows flash EEPROMS to be used as mass storage (eg: instead of magnetic disks). Non-deleted files are duplicated in a reserve block before the active block is erased. This enables the space occupied by deleted files in the active block to be released during the clean-up operation.