The physical migration is a transfer of data from one storage media to another. It is performed whenever one of them is declared obsolete. We can identify two types of hardware obsolescence:
- Physical obsolescencethat is to say the media degradation. The report of the National Academy of Sciences published in March 2010 (1) outlines the many concerns of professional of digital long term preservation because of the existence of damages on media commonly used. The report calls on policy makers to release the studies on the subject by making appeals to ambitious plans to replace the current technology of optical recording (CD-R AND DVD-R), based for now on physicochemical processes complex and poorly controlled, by robust and predictable technology .
- Technological obsolescence : when the reading materials and spare parts tend to disappear and / or when the manufacturer stopped to offer technical support to its users.
The monitoring of archiving equipment is performed at CINES by experts in their technological activities. This work is complemented by integrity checks supported by the technologies used (bit parity on RAID 5 technology, etc..) and business integrity checks (regular calculation and comparison between the checksum of each archived file with the checksum calculated when archiving the file).