4 ms·

Anyway, since nobody much seems to realise this is quite a big deal, I will share the explainer I wrote yesterday: https://www.theregister.com/2025/11/07/unix_

Anyway, since nobody much seems to realise this is quite a big deal, I will share the explainer I wrote yesterday: https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovered/ https://www.theregister.com/2025/11/07/unix_fourth_edition_t... Unix V4 is otherwise lost. It was the first version in C.

mongol 1y ago
Interesting article. I agree it is kind of a big deal. Certainly worth the effort to try to restore
nullhole 1y ago
The bit in the article about the recovery procedure, which involves dumping info from the tape into '100-ish GB of RAM' and then using software to analyze it stuck out to me. This video on the linked github page for the analysis software[1] is interesting: https://www.youtube.com/watch?v=7YoolSAHR5w&t=4200s https://www.youtube.com/watch?v=7YoolSAHR5w&t=4200s [1] https://github.com/LenShustek/readtape https://github.com/LenShustek/readtape
- kragen 1y ago
  Well, the tape may not survive its second pass across the read head, so it's good to capture the analog waveform in as much fidelity as possible.
  - hunter2_ 1y ago
    I wonder if they'll find it suitable to bake [0] the tape first, which is quite popular in the audio restoration world but I'm not sure how much it applies to computer tape. [0] https://en.wikipedia.org/wiki/Sticky-shed_syndrome https://en.wikipedia.org/wiki/Sticky-shed_syndrome
    - debugnik 1y ago
      I don't know much about tapes but it seems to apply, since the post mentions it: > I'm hoping I don't have to bake it, since that takes a day
- sedatk 1y ago
  What a fantastic talk! Thanks for sharing.
avar 1y ago
> This is rare enough that I'm pushing the recovery > of it up near the top of my project queue. The reader is left to wonder what the software librarian at the Computer History Museum could have possibly found recently that warrants a placement ahead of Unix v4 in their project queue. A copy of Atlantian Unix from the ancient Library of Alexandria?
- gregw2 1y ago
  Perhaps a prior promise to someone else?
  - mbreese 1y ago
    Or you know... just the definition of a FIFO Queue. I mean, using a FILO Stack to organize your work would certainly be a choice...
    - rtkwe 1y ago
      Definitionally if they're "pushing it near the top" they're not only using FIFO, there's a priority ordering involved... My guess is there's stuff in progress and maybe they need to arrange access to or setup the readers for a tape that old and of potentially unknown format.
      - nish__ 1y ago
        Yes it's probably better to finish in progress stuff first.
        rtkwe 1y ago
        So much of this is old and potentially delicate and they don't have unlimited space to work in so they'd have to pack up some other in progress digitization project to setup the tape flux digitizer and maybe have to arrange to get the correct one for this type of tape too.

mongol 1y ago

Interesting article. I agree it is kind of a big deal. Certainly worth the effort to try to restore

nullhole 1y ago

The bit in the article about the recovery procedure, which involves dumping info from the tape into '100-ish GB of RAM' and then using software to analyze it stuck out to me. This video on the linked github page for the analysis software[1] is interesting: https://www.youtube.com/watch?v=7YoolSAHR5w&t=4200s https://www.youtube.com/watch?v=7YoolSAHR5w&t=4200s [1] https://github.com/LenShustek/readtape https://github.com/LenShustek/readtape

kragen 1y ago
Well, the tape may not survive its second pass across the read head, so it's good to capture the analog waveform in as much fidelity as possible.
- hunter2_ 1y ago
  I wonder if they'll find it suitable to bake [0] the tape first, which is quite popular in the audio restoration world but I'm not sure how much it applies to computer tape. [0] https://en.wikipedia.org/wiki/Sticky-shed_syndrome https://en.wikipedia.org/wiki/Sticky-shed_syndrome
  - debugnik 1y ago
    I don't know much about tapes but it seems to apply, since the post mentions it: > I'm hoping I don't have to bake it, since that takes a day
sedatk 1y ago
What a fantastic talk! Thanks for sharing.

avar 1y ago

> This is rare enough that I'm pushing the recovery > of it up near the top of my project queue. The reader is left to wonder what the software librarian at the Computer History Museum could have possibly found recently that warrants a placement ahead of Unix v4 in their project queue. A copy of Atlantian Unix from the ancient Library of Alexandria?

gregw2 1y ago
Perhaps a prior promise to someone else?
- mbreese 1y ago
  Or you know... just the definition of a FIFO Queue. I mean, using a FILO Stack to organize your work would certainly be a choice...
  - rtkwe 1y ago
    Definitionally if they're "pushing it near the top" they're not only using FIFO, there's a priority ordering involved... My guess is there's stuff in progress and maybe they need to arrange access to or setup the readers for a tape that old and of potentially unknown format.
    - nish__ 1y ago
      Yes it's probably better to finish in progress stuff first.
      - rtkwe 1y ago
        So much of this is old and potentially delicate and they don't have unlimited space to work in so they'd have to pack up some other in progress digitization project to setup the tape flux digitizer and maybe have to arrange to get the correct one for this type of tape too.