What do government and corporate data archives do?
Surely a long-lived company like IBM has already had
to deal with this
problem?
They deal with the problem by throwing things away. There are essentially
no corporate archives of software older than a few decades. This goes back
to the discussions here a while back about companies discarding software
after a product's life ends.
One of the things I've been disturbed to discover is CHM appears to be one
of the few institutions who are attempting to archive software.
Corporate archives today are essentially all paper or microform. Trying to
deal with digital content is not a solved problem there. If you look at the
literature, they are only thinking in terms of documents, not software, with
the exception of trying to preserve some subset of software needed for document
recovery.