Preservation - Check

The following pages in this section describe the processes involved in active preservation services.

A service that can verify if the stored objects and files remain consistent over time helps in systems where these objects can be distributed over many platforms, some of which may not have a bit-checker embedded. Typically this is done by generating a checksum when the file is first saved and stored, and later comparing this with a newly generated checksum to identify any differences between the two.

This same process can also be used to verify the authenticity of a remotely stored file. If the checksum is not the same but the file is still readable then it may have been changed and no longer be the authentic copy.

In systems where there are many ways of changing the contents of a file, it is important to maintain authenticity and to verify the consistency of the bits on disk.