The archive is currently backed up incrementally each evening and in its entirety each month via the departmental tape-based system.
Plans are being made to produce an iso image with the mathematical contents of the archive. The latest such cdrom image will be available as
http://hopf.math.purdue.edu/HopfArchive-XX-200Y.iso .This file will be approximately 600 megabytes. On many OS's this iso image can be mounted as a file sytem without converting to a physical CD.
Note that these images are just copies of the Hopf archive directory systems. There may be mysterious working files cruft not intended for the light of day. More importantly, due to differences in paths and the use of perl scripts in the Hopf html documents, the menus most likely will not work on your home system. If anyone wants to volunteer to massage these scripts to fit a generic unix or windows environment, that would be great with me.
Still, Netscape with the right helper applications will let you traverse the directory tree in a useful manner. On a laptop, the best bet there might be to use Adobe Acroreader along with Netscape.