The problem of readability of (very) old data from a backup is twofold: a) is the data physically readable (the bits) and b) can those bits be translated into meaningful data (ie is the file-format still supported by current software or is the original software still around and executable on current operating systems or can the OS needed to execute the software for reading the data-file installed on current hardware or can the old hardware with the old OS needed to execute the original software for reading the data-file be connected to your current network?

So, for archiving data you need to be very conservative in both physical as well as "soft" format of the data-backup. The physical problem is the easiest to solve (copy the backups to newer media every few years). A similar technique could be applied to the "soft" problem at the same time: when copying to newer media you could convert the files into a more modern file-format.

So it is not going to be a set-and-forget solution (putting the backup-media into a file-cabinet in the cellar). Because before you know it it cannot be retrieved into a meaningful form.

The end-result for me is that my portable USB-drive contains excel-files originally created with Lotus 1-2-3 in DOS on my XT (remember that one :crazy:?). Begs the question why I keep them though, I haven't touched them since I converted them into Excel about 7 years ago or so.... But I keep faithfully copying them over whenever I move to a next backup-solution...