Longterm preservation defines Longterm as a 5 years period, keeping in
mind that after 5 years a new decade of computer -programs, -model, -
formats and processing begins.
Data curation centers therefore transfer the bitstream regularly to
new media, new harddisks, CDs, DVDs, etc.
The bitstream should be recorded at least in two copies in different
Concerning the formats Sebastians notice is a first hint. Some
formats, like PDF/A have an open documentation and can therefore be
reconstructed. It is best to rely on these formats. TEI/XML is as well
a good way.
Berlin-Brandenburg Academy of Sciences