I've mentioned this before, but I have available backups of pretty much every operating system disk that I've used since oh about 1990. I've got floppies and tapes of older setups but it's getting doubtful they can read anymore. In the early 90's I managed a serious data archive where they kept duplicates of everything going back to 1975. Tape vaults in a temperature controlled clean room. What I've got currently isn't nearly that ambitious. But it opens the possibility that I could extend this blog backwards by pulling in rantings from some old emails and NNTP posts. Maybe another five years. Maybe more. I probably need to back it all up onto some new media pretty soon 'cause I'm down to one copy.

After fifteen years you've got a serious set of problems to deal with. After ten years, even the temperature controlled tape has started to seriously oxidize. Half the tapes are damaged so badly you can't re-assemble the remaining bits. You can scan the raw tape into a memory block and try and collect whatever pieces are left.

That's why we had duplicate archives. Everything stored twice on separate tapes. After ten years, the odds of a single tape oxidizing beyond readability were about 50/50. Our success rate, while striving for perfection - failed at about year fifteen. Media always deteriorates. You can only slow it down.

But first you've got to scan the tape. This requires having in working order a tape machine that's physically compatible with the media formats of that time period, and also a software program that would be able to assemble the original data format of whatever you were trying to extract.

Or keep copying it onto new media... That's the only reason my data has held out so long. Though I still keep the originals. Instead of tape, I store the hard drives. It's getting harder to find a compatible SCSI card for a couple of them though. Optical media like CD-R/RW and DVD-R/RW also suffer shelf life problems. They deteriorate. About ten to fifteen years.