Long Term Archival
With regards to long term storage, there have been several technologies, though only a few remain.
Kodak produced their 74min 650MB Gold plated discs in the 1995-2000's or so, and were the single best disc for long term storage (as far as I know - no source - might be incorrect) -- up to 200 years in accelerated tests.
Kodak also produced 80min 700MB Silver+Gold plated discs in 1998-2003 or so, and were also very good for long term storage, claimed to last up to 100 years in accelerated tests.
I still have quite a few of both types (burned in 1996, and 1998 up to 2005 when DVD's took over), that still works flawlessly - even though quite a few other brands of cd's and dvd's have failed miserably.
VHS tapes, Casette Tapes, DAT Tapes, Floppies and Harddiscs of various types (IDE, ATA, and SCSI) most likely have failed at least some bits (even though they may seem to read correctly -
Bit rot is most likely present in every type).
With Harddiscs in particular, I have seen so many fail, that I tend to buy new ones every 2-3 years, BEFORE they have a chance to fail - this is just about every brand - Seagate, IBM, Maxtor, Connor, Western Digital, Hitachi, ... well name one, and it will most likely fail within 2-5 years if used often enough --- though proper cooling (much more that the producers claim is necessary) -- can prolong the lifespan.
Recently when researching long-term storage, I stumbled upon a "new" format --- Milleniata ... a Disc format designed from the start to last 1000 years - based on Stone inside the disc, instead of dyes. Go watch Milleniata's Promotional video's they give a nice overview. At first they produced 4.7GB DVD-R's and have now begun manufacturing 25GB BD-R's. It requires a very high powered laser to burn the stone-layer in the disc, and the burner itself have to be "
M-DISC" certified --- though,
I have read that some recorders can be firmware upgraded to be able to cope with M-DISC's (at probably a lot lower write speed than their normally stated max, as the M-DISC requires very high powered laser (same goes for higher speed - thus if you lower speed, you MIGHT be able to burn M-DISC's - with the right firmware)
Finally - if you really want to preserve "stuff" - implementing a Parity area -- like e.g. Nero's SecurDisc implementation, or simply PAR2 - or another kind of Parity writing software and md5 sums to ensure that the data really IS intact, is some of the way to ensuring proper long term archival of data.
And yes, DNA is quite resilient, with many
safeguards against mutations - Mutations still do occur --- but at least in data preservation with parity sets and md5 sums one will be able to detect it at the very least.