Apparatus for keeping several versions of a file

摘要

An apparatus for keeping several versions of a file includes a memory and an overwriting unit coupled to the memory. An initial version of the file is stored in a first area of the memory, and a current version is stored in a second area of the memory, the current version resulting from a modification of the initial version. The overwriting unit substitutes the current version for the initial version in response to a validation signal. The validation signal is produced after the current version has been permanently stored.