Comment by reactordev
1 month ago
Please let there be an ultimate force in the universe that spared this tape from tape degradation and/or magnetization that it can be read and extracted into a raw dump fs that we can preserve for all time. (fingers crossed)
Tapes from back then haven’t held up over the years. It all depends on the environment it was stored in.
I remember reading we're nearing a timeframe where VHS and cassette tapes made in the <=1980s will start degrading pretty seriously. So if you own lots of VHS or camcorder tapes you have a relatively short window to save old family videos... or just deal with fuzzy images and bad audio.
Somewhat related, there are people doing amazing things by modifying VHS players and tapping into the raw output from the tape heads (bypassing all of the player's other electronics), and then using modern signal processing techniques to extract unbelievable great footage from old tapes.
Check out this extraction/decoding of a 1987 VHS recording of The Cure:
https://www.youtube.com/watch?v=ks1wE_NXWv8
Play if full screen at whatever the highest resolution your screen can take advantage of, It's amazing! Check out the quality of the big headshots of Robert Smith, the resolution of stuff like his hair is way beyond what I believed VHS to be capable of - based on growing up recording similar music acts in the 70s and 80s.
Here's the software (and descriptions of the hardware and VHS player mods) they use:
https://github.com/oyvindln/vhs-decode
I suspect the recording technique/format on those is a similar analog signal on the tape - and from The Reg's article (quoting various sources) it sounds like they're already planning on similar approach:
"The software librarian at the CHM is the redoubtable Al Kossow of Bitsavers, who commented in the thread that he is on the case. On the TUHS mailing list, he explained how he plans to do it:
taping off the head read amplifier, using a multi-channel high speed analog to digital converter which dumps into 100-ish gigabytes of RAM, then an analysis program Len Shustek wrote: https://github.com/LenShustek/readtape
It is a '70s 1200ft 3M tape, likely 9 track, which has a pretty good chance of being recoverable."
I recently went through this. The problem is finding VCR's... there arent any.
And then the ones with manual tracking are even more rare, or out of the price range, which you likely need as the tracks degrade.
There is one parity bit per 8 data bits, which is decently resilient - plus the recovery is pretty simple on the occasional bit flip. Combine that with the fact you can reference other sources to make up for missing/corrupted files - I think the chance that this is recoverable is pretty high provided the machine reading it is high quality. Checksumming on the source was unfortunately not commonplace until Unix 7, so it's unlikely there was any software-level integrity checks here. The tape looks like it was stored in a sealed container which is a very good sign. Those older tapes are actually more resilient than the later generation of tapes, and don't usually degrade the same way even with exposure to humidity.