We run the www.cryptomuseum.com website. On our (physical) collection we have German and Russian wire recorders, the small ones. Really beatiful marvels of engineering from the past.
It might be a good idea to klick this link for the Protona wire recorder from Austria. This recorder was very widely used by all secret services, including the CIA. It had a secret microphone build inside a watch. The watch has no mechanics and is not running. The story goes that an agent was caught on an airport since he wore 2 watches: The one that worked and the one with the microphone. Anyway, enjoy this link:
Well, I personally loved Pratchett's idea for his Discword computer, "Hex". So an online search to see if I could find more details turned up this image, which appeared, briefly, in the "Hogfather" DVD. Apparently, there's also a guy online, who sells all sorts of Discworld paraphernalia, and provides these as stickers, etc.
After all, who knows... "ant colony optimization algorithms" and all that.
Anyway, for wire storage of audio frequencies I suppose I'd expect the physical extent of the magnetic domains to be rather small, sub-millimeter, even at two feet per second. And so accordingly, the field strengths as well.
But for useful non-electronic storage of binary data, as an alternative to punch-cards or paper-tape, it may not need to be so limited. Especially for several spools geared to run in parallel.
Then, if this type of wire is of an alloy *particularly* suitable for magnetization, then reading back your data might be accomplished with a set of compass needles ( mechanically interfaced through sensitive torque-amplifies ). Or electrically interfaced through the contacts elements of reed-relays.
And, perhaps, mechanically writing data might be accomplished with a device having a set of small hammers with magnetized heads.
A perfect project for folks who have the right tools and too much time on their hands!
Out of curiosity, any idea of the typical range of strength of magnetic fields stored on the recording wire? Sufficient enough to deflect a compass needle? Activate a sensitive reed relay?
... and aren't certain types of insects sensitive to magnetic fields?
My dad used wire recorders back in his military days. I've never personally seen one and your photo of the wore spool is the first I've seen of that. I do have some old reel to reel tapes that have voices of my parents when they were quite young and may have my grand parents on them.
I found an old tube reel to reel player but haven't gotten around to getting it up and running yet. I suppose I should soon or the tapes may disintegrate.
Wow -- I'd never even thought of using them for CNC machines -- but it makes sense -- about 15 years ago I went to a PCB manufacturing facility here in town to get a few boards made and they still used paper tape to control their CNC machines (like the drills and suchlike)