The gap between knowledge capture today and the ability to access that captured knowledge in the future. Long term digital storage will only store bits of data and there is no guarantee a future can:
- firstly recognise any surface markings as information
- read the bits as stored (0’s and 1’s)
- understanding the encoding the bits represent (are they letters, numbers, symbols)
- understand what the structures of the bits mean (records)
For example, Laser writing in glass for dense, fast and efficient archival data storage | Nature describes etching in glass that can last 10,000 years but reading it back requires wide-field transmission optical microscopy with a detection numerical aperture (NA) of 0.6 because lower NA values do not sufficiently resolve signals from adjacent voxels, and higher NA values introduce more significant spherical aberration with depth.
Already we have tapes and disks that cannot be read and video games that cannot be played because the compatible hardware is unavailable.